Sosipatros Boikos | Virginia Commonwealth University (original) (raw)

Papers by Sosipatros Boikos

Research paper thumbnail of The role of germline AIP, MEN1, PRKAR1A, CDKN1B and CDKN2C mutations in causing pituitary adenomas in a large cohort of children, adolescents, and patients with genetic syndromes

Clinical Genetics, 2010

Stratakis CA, Tichomirowa MA, Boikos S, Azevedo MF, Lodish M, Martari M, Verma S, Daly AF, Raygad... more Stratakis CA, Tichomirowa MA, Boikos S, Azevedo MF, Lodish M, Martari M, Verma S, Daly AF, Raygada M, Keil MF, Papademetriou J, Drori-Herishanu L, Horvath A, Tsang KM, Nesterova M, Franklin S, Vanbellinghen J-F, Bours V, Salvatori R, Beckers A. The role of germline AIP, MEN1, PRKAR1A, CDKN1B and CDKN2C mutations in causing pituitary adenomas in a large cohort of children, adolescents, and patients with genetic syndromes.The prevalence of germline mutations in MEN1, AIP, PRKAR1A, CDKN1B and CDKN2CI is unknown among pediatric patients with pituitary adenomas (PA). In this study, we screened children with PA for mutations in these genes; somatic GNAS mutations were also studied in a limited number of growth hormone (GH) or prolactin (PRL)-secreting PA. We studied 74 and 6 patients with either isolated Cushing disease (CD) or GH- or PRL-secreting PA, respectively. We also screened four pediatric patients with CD, and four with GH/PRL-secreting tumors who had some syndromic features. There was one AIP mutation (p.Lys103Arg) among 74 CD patients. Two MEN1 mutations that occurred in patients with recurrent or difficult-to-treat disease were found among patients with CD. There was one MEN1 and three AIP mutations (p.Gln307ProfsX104, p.Pro114fsX, p.Lys241X) among pediatric patients with isolated GH- or PRL-secreting PA and one additional MEN1 mutation in a patient with positive family history. There were no mutations in the PRKAR1A, CDKN1B, CDKN2C or GNAS genes. Thus, germline AIP or MEN1 gene mutations are frequent among pediatric patients with GH- or PRL-secreting PA but are significantly rarer in pediatric CD; PRKAR1A mutations are not present in PA outside of Carney complex.

Research paper thumbnail of A novel, non-functional, COL1A1 polymorphism is not associated with lumbar disk disease in young male Greek subjects unlike that of the Sp1 site

A novel, non-functional, COL1A1 polymorphism is not associated with lumbar disk disease in young ... more A novel, non-functional, COL1A1 polymorphism is not associated with lumbar disk disease in young male Greek subjects unlike that of the Sp1 site ABSTRACT OBJECTIVE: We recently reported the association of the Sp1 site polymorphism of the COL1A1 gene with lumbar disk disease (LDD). In the present study we searched for a different polymorphism of the COL1A1 gene (which is usually not in linkage disequilibrium with the Sp1 site) in subjects with LDD. DESIGN: Blood was collected from 24 Greek army recruits, aged 29±7.6 years, with LDD, and 66 healthy men, aged 26±4.38 years, matched for body mass index (BMI) and age, with normal BMD and with no history of trauma or fractures, who served as controls. DNA was extracted and the COL1A1 gene was sequenced. Of the control subjects, 12 were army recruits and 54 were selected from the general population. RESULTS: The four base-pair insertion polymorphism in the COL1A1 gene analyzed by polymerase chain reaction amplification of DNA produces two different fragments (alleles A1 and A2): 14 patients (58.3%) were homozygous for A2A2, versus 35 controls (53%), while 3 patients (12.5%) were A1A1, and 8 of the control subjects (12%) had this genotype. There were no statistically significant differences in the presence of the two alleles of this polymorphism between patients with LDD and control subjects. CONCLUSIONS: A four base-pair insertion polymorphism of the COL1A1 gene is not associated with the presence of LDD in young males, unlike the Sp1 site polymorphism of the same gene. These data reinforce the association between LDD and the functional polymorphisms of the Sp1 site by showing that other polymorphic sites of the of the COL1A1 gene in the same population of patients are not linked to the disease.

Research paper thumbnail of Effects of Cushing Disease on Bone Mineral Density in a Pediatric Population

Journal of Pediatrics, 2010

Objective-To evaluate bone mineral density (BMD) in children with Cushing disease before and afte... more Objective-To evaluate bone mineral density (BMD) in children with Cushing disease before and after transphenoidal surgery (TSS).

Research paper thumbnail of Genetics of adrenal tumors associated with Cushing's syndrome: a new classification for bilateral adrenocortical hyperplasias

Nature Clinical Practice Endocrinology & Metabolism, 2007

Adrenocortical causes of Cushing'... more Adrenocortical causes of Cushing's syndrome include the following: common cortisol-producing adenomas, which are usually isolated (without associated tumors) and sporadic (without a family history); rare, but often clinically devastating, adrenocortical carcinomas; and a spectrum of adrenocorticotropin-independent, and almost always bilateral, hyperplasias, which are not rare, and are the most recently recognized cause. The majority of benign lesions of the adrenal cortex seem to be linked to abnormalities of the cyclic AMP signaling pathway, whereas cancer is linked to aberrant expression of insulin-like growth factor II, tumor protein p53 and related molecules. In this article, we propose a new clinical classification and nomenclature for the various forms of adrenocorticotropin-independent adrenocortical hyperplasias that is based on their histologic and genetic features. We also review the molecular genetics of adrenocortical tumors, including recent discoveries relating to the role of phosphodiesterase 11A. This is a timely Review because of recent advances in the clinical and molecular understanding of these diseases.

Research paper thumbnail of Clinical and molecular genetics of patients with the Carney–Stratakis syndrome and germline mutations of the genes coding for the succinate dehydrogenase subunits SDHB, SDHC, and SDHD

European Journal of Human Genetics, 2008

Gastrointestinal stromal tumors (GISTs) may be caused by germline mutations of the KIT and platel... more Gastrointestinal stromal tumors (GISTs) may be caused by germline mutations of the KIT and plateletderived growth factor receptor-a (PDGFRA) genes and treated by Imatinib mesylate (STI571) or other protein tyrosine kinase inhibitors. However, not all GISTs harbor these genetic defects and several do not respond to STI571 suggesting that other molecular mechanisms may be implicated in GIST pathogenesis. In a subset of patients with GISTs, the lesions are associated with paragangliomas; the condition is familial and transmitted as an autosomal-dominant trait. We investigated 11 patients with the dyad of 'paraganglioma and gastric stromal sarcoma'; in eight (from seven unrelated families), the GISTs were caused by germline mutations of the genes encoding subunits B, C, or D (the SDHB, SDHC and SDHD genes, respectively). In this report, we present the molecular effects of these mutations on these genes and the clinical information on the patients. We conclude that succinate dehydrogenase deficiency may be the

Research paper thumbnail of Carney complex: the first 20 years

Current Opinion in Oncology, 2007

The purpose of this review is to comment on the current findings on Carney complex, a dominantly ... more The purpose of this review is to comment on the current findings on Carney complex, a dominantly inherited disease and a unique multiple endocrine neoplasia syndrome. Sequencing of the PRKAR1A gene in more than 150 kindreds has revealed a number of pathogenic mutations; in more than 90% of the cases, the sequence change was predicted to lead to a premature stop codon and, thus, mutant mRNAs were subject to nonsense-mediated mRNA decay. In Carney complex syndrome cells carrying these mutations, protein kinase A activity is irregularly stimulated by cAMP. Mutations that did not lead to a premature stop codon have also been described; these were also associated with abnormal protein kinase A activity. Animal models of the disease have been recently developed; they reproduced some of the stigmata of Carney complex syndrome but not all. Genetic testing of patients' family members has been introduced in recent years, leading to early detection and a better overall prognosis. New treatments have yet to be applied; the elucidation of the molecular pathways regulated by PRKAR1A holds the promise of leading to molecularly designed therapies.

Research paper thumbnail of Throat Clearing — A Novel Asthma Symptom in Children

New England Journal of Medicine, 2003

Research paper thumbnail of Genetics of Carney Triad: Recurrent Losses at Chromosome 1 but Lack of Germline Mutations in Genes Associated with Paragangliomas and Gastrointestinal Stromal Tumors

Context: Carney triad (CT) describes the association of paragangliomas (PGLs) with gastrointestin... more Context: Carney triad (CT) describes the association of paragangliomas (PGLs) with gastrointestinal stromal tumors (GISTs) and pulmonary chondromas. Inactivating mutations of the mitochondrial complex II succinate dehydrogenase (SDH) enzyme subunits SDHB, SDHC, and SDHD are found in PGLs, gain-of-function mutations of c-kit (KIT), and platelet-derived growth factor receptor A (PDGFRA) in GISTs.

Research paper thumbnail of 17q22-24 Chromosomal Losses and Alterations of Protein Kinase A Subunit Expression and Activity in Adrenocorticotropin-Independent Macronodular Adrenal Hyperplasia

Primary adrenocortical hyperplasias leading to Cushing syndrome include primary pigmented nodular... more Primary adrenocortical hyperplasias leading to Cushing syndrome include primary pigmented nodular adrenocortical disease and ACTH-independent macronodular adrenal hyperplasia (AIMAH). Inactivating mutations of the 17q22-24-located PRKAR1A gene, coding for the type 1A regulatory subunit of protein kinase A (PKA), cause primary pigmented nodular adrenocortical disease and the multiple endocrine neoplasia syndrome Carney complex. PRKAR1A mutations and 17q22-24 chromosomal losses have been found in sporadic adrenal tumors and are associated with aberrant PKA signaling.

Research paper thumbnail of Adrenal Hyperplasia and Adenomas Are Associated with Inhibition of Phosphodiesterase 11A in Carriers of PDE11A Sequence Variants That Are Frequent in the Population

Several types of adrenocortical tumors that lead to Cushing syndrome may be caused by aberrant cy... more Several types of adrenocortical tumors that lead to Cushing syndrome may be caused by aberrant cyclic AMP (cAMP) signaling. We recently identified patients with micronodular adrenocortical hyperplasia who were carriers of inactivating mutations in the 2q-located phosphodiesterase 11A (PDE11A)

Research paper thumbnail of A cAMP-specific phosphodiesterase (PDE8B) that is mutated in adrenal hyperplasia is expressed widely in human and mouse tissues: a novel PDE8B isoform in human adrenal cortex

European Journal of Human Genetics, 2008

Bilateral adrenocortical hyperplasia (BAH) is the second most common cause of corticotropinindepe... more Bilateral adrenocortical hyperplasia (BAH) is the second most common cause of corticotropinindependent Cushing syndrome (CS). Genetic forms of BAH have been associated with complex syndromes such as Carney Complex and McCune Albright syndrome or may present as isolated micronodular adrenocortical disease (iMAD) usually in children and young adults with CS. A genome-wide association study identified inactivating phosphodiesterase (PDE) 11A (PDE11A) sequencing defects as low-penetrance predisposing factors for iMAD and related abnormalities; we also described a mutation (c.914A>C/H305P) in cAMP-specific PDE8B, in a patient with iMAD. In this study we further characterize this mutation; we also found a novel PDE8B isoform, highly expressed in the adrenal gland. This mutation is shown to significantly affect the ability of the protein to degrade cAMP in vitro. Tumor tissues from patients with iMAD and no mutations in the coding PDE8B sequence or any other related genes (PRKAR1A, PDE11A) showed down-regulated PDE8B expression (compared to normal adrenal cortex). Pde8b is detectable in the adrenal gland of newborn mice and is widely expressed in other mouse tissues. We conclude that PDE8B is another PDE gene linked to iMAD; it is a candidate causative gene for other adrenocortical lesions linked to the cAMPsignaling pathway, and possibly for tumors in other tissues.

Research paper thumbnail of Multiple Gastrointestinal Stromal and Other Tumors Caused by Platelet-Derived Growth Factor Receptor Gene Mutations: A Case Associated with a Germline V561D Defect

Research paper thumbnail of Mutations in Regulatory Subunit Type 1A of Cyclic Adenosine 5'-Monophosphate-Dependent Protein Kinase (PRKAR1A): Phenotype Analysis in 353 Patients and 80 Different Genotypes

Journal of Clinical Endocrinology & Metabolism, 2009

The &... more The "complex of myxomas, spotty skin pigmentation, and endocrine overactivity," or "Carney complex" (CNC), is caused by inactivating mutations of the regulatory subunit type 1A of the cAMP-dependent protein kinase (PRKAR1A) gene and as yet unknown defect(s) in other gene(s). Delineation of a genotype-phenotype correlation for CNC patients is essential for understanding PRKAR1A function and providing counseling and preventive care.

Research paper thumbnail of Association of the M1V PRKAR1A Mutation with Primary Pigmented Nodular Adrenocortical Disease in Two Large Families

Journal of Clinical Endocrinology & Metabolism, 2010

Carney complex (CNC) is a familial multiple neoplasia syndrome frequently associated with primary... more Carney complex (CNC) is a familial multiple neoplasia syndrome frequently associated with primary pigmented nodular adrenocortical disease (PPNAD), a bilateral form of micronodular adrenal hyperplasia that leads to Cushing's syndrome (CS). Germline PRKAR1A mutations cause CNC and only rarely isolated PPNAD. PRKAR1A mutation analysis in two large families with CS and no other CNC manifestations demonstrated a M1V germline mutation; a total of 21 asymptomatic individuals were screened, and mutation carriers were evaluated for CNC. The mutation was expressed in vitro and functionally tested for its effects on protein kinase A function. Presymptomatic testing identified five first-degree relatives who were M1V carriers and who were all diagnosed with subclinical, mild CS at ages ranging from 20-56 yr. There were no other signs of CNC. In a cell-free system, we detected a shorter compared with the wild-type type 1alpha regulatory subunit of protein kinase A (PRKAR1A) protein (43 kDa). This was not identified in cell lines from the patients or in transfection experiments in HEK293 cells that showed no detectable PRKAR1A protein from the M1V-bearing constructs. In these cells, the mutant mRNA was expressed in a 1:1 ratio. In two large families, the M1V PRKAR1A mutation resulted in a PPNAD-only phenotype with significant variability both in terms of age of onset and clinical severity. Expression studies showed a unique effect of this sequence change. This study has implications for genetic counseling of carriers of this PRKAR1A mutation and patients with CNC and PPNAD and for the study of PRKAR1A-related tumorigenesis.

Research paper thumbnail of Differences in cortisol levels and body mass index between East Asians and Caucasians with Cushing's syndrome: an ?East Asian? phenotype for Cushing syndrome

Clinical Endocrinology, 2007

Research paper thumbnail of Adrenal Hyperplasia and Adenomas Are Associated with Inhibition of Phosphodiesterase 11A in Carriers of PDE11A Sequence Variants That Are Frequent in the Population

Cancer Research, 2006

Several types of adrenocortical tumors that lead to Cushing syndrome may be caused by aberrant cy... more Several types of adrenocortical tumors that lead to Cushing syndrome may be caused by aberrant cyclic AMP (cAMP) signaling. We recently identified patients with micronodular adrenocortical hyperplasia who were carriers of inactivating mutations in the 2q-located phosphodiesterase 11A (PDE11A) gene. We now studied the frequency of two missense substitutions, R804H and R867G, in conserved regions of the enzyme in several sets of normal controls, including 745 individuals enrolled in a longitudinal cohort study, the New York Cancer Project. In the latter, we also screened for the presence of the previously identified PDE11A nonsense mutations. R804H and R867G were frequent among patients with adrenocortical tumors; although statistical significance was not reached, these variants affected significantly enzymatic function in vitro with variable increases in cAMP and/or cyclic guanosine 3 ¶,5 ¶-monophosphate levels in HeLa and HEK293 cells. Adrenocortical tissues carrying the R804H mutation showed 2q allelic losses and higher cyclic nucleotide levels and cAMP-responsive element binding protein phosphorylation. We conclude that missense mutations of the PDE11A gene that affect enzymatic activity in vitro are present in the general population; protein-truncating PDE11A mutations may also contribute to a predisposition to other tumors, in addition to their association with adrenocortical hyperplasia. We speculate that PDE11A genetic defects may be associated with adrenal pathology in a wider than previously suspected clinical spectrum that includes asymptomatic individuals. (Cancer Res 2006; 66(24): 11571-5)

Research paper thumbnail of Polymorphisms of the Vitamin D Receptor Gene and Stress Fractures

Hormone and Metabolic Research, 2009

Our aim was to evaluate the association between VDR polymorphisms and calcaneal Stiffness Index (... more Our aim was to evaluate the association between VDR polymorphisms and calcaneal Stiffness Index (SI) with stress fractures in a case control study including male military personnel. Thirtytwo patients with stress fractures were matched with 32 uninjured healthy volunteers (controls), by gender, age, height, body weight, and level of physical activity. The two groups were genotyped for the FokI, BsmI, ApaI, and TaqI polymorphisms of the VDR gene with PCR-RFLP method. In addition, calcaneal SI was measured by heel quantitative ultrasound in both groups. Data were analyzed by chi-squared test and logistic regression analysis. The f allele was significantly more frequent in patients than in controls (p=0.013), while the B allele showed such a tendency without reaching statistical significance (p=0.052). Among the entire cohort, a 2.7-fold and a 2.0-fold increase in risk of stress fractures was associated with the f and B alleles (OR, 2.7, 95% CI, 1.2-5.9; p=0.014 and OR, 2.0, 95% CI, 1.0-4.1; p=0.053, respectively). No statistically significant association was found between the incidence of stress fractures and t or a alleles. Decreased Tscores were also associated with the presence of f and B alleles. Mean values of T-scores of SI were statistically significantly lower in patients than in controls (p=0.018). These results suggest that the FokI and BsmI polymorphisms of the VDR gene could be associated with increased risk of stress fractures among military personnel. Moreover, a low calcaneal SI could represent a measurable index of this increased risk.

Research paper thumbnail of Mouse Prkar1a haploinsufficiency leads to an increase in tumors in the Trp53+/- or Rb1+/- backgrounds and chemically induced skin papillomas by dysregulation of the cell cycle and Wnt signaling

Human Molecular Genetics, 2010

PRKAR1A inactivation leads to dysregulated cAMP signaling and Carney complex (CNC) in humans, a s... more PRKAR1A inactivation leads to dysregulated cAMP signaling and Carney complex (CNC) in humans, a syndrome associated with skin, endocrine and other tumors. The CNC phenotype is not easily explained by the ubiquitous cAMP signaling defect; furthermore, Prkar1a 1/ 2 mice did not develop skin and other CNC tumors. To identify whether a Prkar1a defect is truly a generic but weak tumorigenic signal that depends on tissue-specific or other factors, we investigated Prkar1a 1/2 mice when bred within the Rb1 1/2 or Trp53 1/2 backgrounds, or treated with a two-step skin carcinogenesis protocol. Prkar1a 1/2 Trp53 1/2 mice developed more sarcomas than Trp53 1/2 mice (P < 0.05) and Prkar1a 1/2 Rb1 1/2 mice grew more (and larger) pituitary and thyroid tumors than Rb1 1/2 mice. All mice with double heterozygosity had significantly reduced life-spans compared with their single-heterozygous counterparts. Prkar1a 1/2 mice also developed more papillomas than wild-type animals. A whole-genome transcriptome profiling of tumors produced by all three models identified Wnt signaling as the main pathway activated by abnormal cAMP signaling, along with cell cycle abnormalities; all changes were confirmed by qRT -PCR array and immunohistochemistry. siRNA down-regulation of Ctnnb1, E2f1 or Cdk4 inhibited proliferation of human adrenal cells bearing a PRKAR1A-inactivating mutation and Prkar1a 1/2 mouse embryonic fibroblasts and arrested both cell lines at the G0/G1 phase of the cell cycle.

Research paper thumbnail of Multiple Gastrointestinal Stromal and Other Tumors Caused by Platelet-Derived Growth Factor Receptor Gene Mutations: A Case Associated with a Germline V561D Defect

Journal of Clinical Endocrinology & Metabolism, 2007

Research paper thumbnail of Novel polymorphisms and lack of mutations in the ACD gene in patients with ACTH resistance syndromes

Clinical Endocrinology, 2007

Objective ACTH resistance is a feature of several human syndromes with known genetic causes, inc... more Objective ACTH resistance is a feature of several human syndromes with known genetic causes, including familial glucocorticoid deficiency (types 1 and 2) and triple A syndrome. However, many patients with ACTH resistance lack an identifiable genetic aetiology. The human homolog of the Acd gene, mutated in a mouse model of adrenal insufficiency, was sequenced in 25 patients with a clinical diagnosis of familial glucocorticoid deficiency or triple A syndrome.Design A 3·4 kilobase genomic fragment containing the entire ACD gene was analysed for mutations in all 25 patients.Setting Samples were obtained by three investigators from different institutions.Patients The primary cohort consisted of 25 unrelated patients, primarily of European or Middle Eastern descent, with a clinical diagnosis of either familial glucocorticoid deficiency (FGD) or triple A syndrome. Patients lacked mutations in other genes known to cause ACTH resistance, including AAAS for patients diagnosed with triple A syndrome and MC2R and MRAP for patients diagnosed with familial glucocorticoid deficiency. Thirty-five additional patients with adrenal disease phenotypes were added to form an expanded cohort of 60 patients.Measurements Identification of DNA sequence changes in the ACD gene in the primary cohort and analysis of putative ACD haplotypes in the expanded cohort.Results No disease-causing mutations were found, but several novel single nucleotide polymorphisms (SNPs) and two putative haplotypes were identified. The overall frequency of SNPs in ACD is low compared to other gene families.Conclusions No mutations were identified in ACD in this collection of patients with ACTH resistance phenotypes. However, the newly identified SNPs in ACD should be more closely examined for possible links to disease.

Research paper thumbnail of The role of germline AIP, MEN1, PRKAR1A, CDKN1B and CDKN2C mutations in causing pituitary adenomas in a large cohort of children, adolescents, and patients with genetic syndromes

Clinical Genetics, 2010

Stratakis CA, Tichomirowa MA, Boikos S, Azevedo MF, Lodish M, Martari M, Verma S, Daly AF, Raygad... more Stratakis CA, Tichomirowa MA, Boikos S, Azevedo MF, Lodish M, Martari M, Verma S, Daly AF, Raygada M, Keil MF, Papademetriou J, Drori-Herishanu L, Horvath A, Tsang KM, Nesterova M, Franklin S, Vanbellinghen J-F, Bours V, Salvatori R, Beckers A. The role of germline AIP, MEN1, PRKAR1A, CDKN1B and CDKN2C mutations in causing pituitary adenomas in a large cohort of children, adolescents, and patients with genetic syndromes.The prevalence of germline mutations in MEN1, AIP, PRKAR1A, CDKN1B and CDKN2CI is unknown among pediatric patients with pituitary adenomas (PA). In this study, we screened children with PA for mutations in these genes; somatic GNAS mutations were also studied in a limited number of growth hormone (GH) or prolactin (PRL)-secreting PA. We studied 74 and 6 patients with either isolated Cushing disease (CD) or GH- or PRL-secreting PA, respectively. We also screened four pediatric patients with CD, and four with GH/PRL-secreting tumors who had some syndromic features. There was one AIP mutation (p.Lys103Arg) among 74 CD patients. Two MEN1 mutations that occurred in patients with recurrent or difficult-to-treat disease were found among patients with CD. There was one MEN1 and three AIP mutations (p.Gln307ProfsX104, p.Pro114fsX, p.Lys241X) among pediatric patients with isolated GH- or PRL-secreting PA and one additional MEN1 mutation in a patient with positive family history. There were no mutations in the PRKAR1A, CDKN1B, CDKN2C or GNAS genes. Thus, germline AIP or MEN1 gene mutations are frequent among pediatric patients with GH- or PRL-secreting PA but are significantly rarer in pediatric CD; PRKAR1A mutations are not present in PA outside of Carney complex.

Research paper thumbnail of A novel, non-functional, COL1A1 polymorphism is not associated with lumbar disk disease in young male Greek subjects unlike that of the Sp1 site

A novel, non-functional, COL1A1 polymorphism is not associated with lumbar disk disease in young ... more A novel, non-functional, COL1A1 polymorphism is not associated with lumbar disk disease in young male Greek subjects unlike that of the Sp1 site ABSTRACT OBJECTIVE: We recently reported the association of the Sp1 site polymorphism of the COL1A1 gene with lumbar disk disease (LDD). In the present study we searched for a different polymorphism of the COL1A1 gene (which is usually not in linkage disequilibrium with the Sp1 site) in subjects with LDD. DESIGN: Blood was collected from 24 Greek army recruits, aged 29±7.6 years, with LDD, and 66 healthy men, aged 26±4.38 years, matched for body mass index (BMI) and age, with normal BMD and with no history of trauma or fractures, who served as controls. DNA was extracted and the COL1A1 gene was sequenced. Of the control subjects, 12 were army recruits and 54 were selected from the general population. RESULTS: The four base-pair insertion polymorphism in the COL1A1 gene analyzed by polymerase chain reaction amplification of DNA produces two different fragments (alleles A1 and A2): 14 patients (58.3%) were homozygous for A2A2, versus 35 controls (53%), while 3 patients (12.5%) were A1A1, and 8 of the control subjects (12%) had this genotype. There were no statistically significant differences in the presence of the two alleles of this polymorphism between patients with LDD and control subjects. CONCLUSIONS: A four base-pair insertion polymorphism of the COL1A1 gene is not associated with the presence of LDD in young males, unlike the Sp1 site polymorphism of the same gene. These data reinforce the association between LDD and the functional polymorphisms of the Sp1 site by showing that other polymorphic sites of the of the COL1A1 gene in the same population of patients are not linked to the disease.

Research paper thumbnail of Effects of Cushing Disease on Bone Mineral Density in a Pediatric Population

Journal of Pediatrics, 2010

Objective-To evaluate bone mineral density (BMD) in children with Cushing disease before and afte... more Objective-To evaluate bone mineral density (BMD) in children with Cushing disease before and after transphenoidal surgery (TSS).

Research paper thumbnail of Genetics of adrenal tumors associated with Cushing's syndrome: a new classification for bilateral adrenocortical hyperplasias

Nature Clinical Practice Endocrinology & Metabolism, 2007

Adrenocortical causes of Cushing&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;... more Adrenocortical causes of Cushing&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s syndrome include the following: common cortisol-producing adenomas, which are usually isolated (without associated tumors) and sporadic (without a family history); rare, but often clinically devastating, adrenocortical carcinomas; and a spectrum of adrenocorticotropin-independent, and almost always bilateral, hyperplasias, which are not rare, and are the most recently recognized cause. The majority of benign lesions of the adrenal cortex seem to be linked to abnormalities of the cyclic AMP signaling pathway, whereas cancer is linked to aberrant expression of insulin-like growth factor II, tumor protein p53 and related molecules. In this article, we propose a new clinical classification and nomenclature for the various forms of adrenocorticotropin-independent adrenocortical hyperplasias that is based on their histologic and genetic features. We also review the molecular genetics of adrenocortical tumors, including recent discoveries relating to the role of phosphodiesterase 11A. This is a timely Review because of recent advances in the clinical and molecular understanding of these diseases.

Research paper thumbnail of Clinical and molecular genetics of patients with the Carney–Stratakis syndrome and germline mutations of the genes coding for the succinate dehydrogenase subunits SDHB, SDHC, and SDHD

European Journal of Human Genetics, 2008

Gastrointestinal stromal tumors (GISTs) may be caused by germline mutations of the KIT and platel... more Gastrointestinal stromal tumors (GISTs) may be caused by germline mutations of the KIT and plateletderived growth factor receptor-a (PDGFRA) genes and treated by Imatinib mesylate (STI571) or other protein tyrosine kinase inhibitors. However, not all GISTs harbor these genetic defects and several do not respond to STI571 suggesting that other molecular mechanisms may be implicated in GIST pathogenesis. In a subset of patients with GISTs, the lesions are associated with paragangliomas; the condition is familial and transmitted as an autosomal-dominant trait. We investigated 11 patients with the dyad of 'paraganglioma and gastric stromal sarcoma'; in eight (from seven unrelated families), the GISTs were caused by germline mutations of the genes encoding subunits B, C, or D (the SDHB, SDHC and SDHD genes, respectively). In this report, we present the molecular effects of these mutations on these genes and the clinical information on the patients. We conclude that succinate dehydrogenase deficiency may be the

Research paper thumbnail of Carney complex: the first 20 years

Current Opinion in Oncology, 2007

The purpose of this review is to comment on the current findings on Carney complex, a dominantly ... more The purpose of this review is to comment on the current findings on Carney complex, a dominantly inherited disease and a unique multiple endocrine neoplasia syndrome. Sequencing of the PRKAR1A gene in more than 150 kindreds has revealed a number of pathogenic mutations; in more than 90% of the cases, the sequence change was predicted to lead to a premature stop codon and, thus, mutant mRNAs were subject to nonsense-mediated mRNA decay. In Carney complex syndrome cells carrying these mutations, protein kinase A activity is irregularly stimulated by cAMP. Mutations that did not lead to a premature stop codon have also been described; these were also associated with abnormal protein kinase A activity. Animal models of the disease have been recently developed; they reproduced some of the stigmata of Carney complex syndrome but not all. Genetic testing of patients&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39; family members has been introduced in recent years, leading to early detection and a better overall prognosis. New treatments have yet to be applied; the elucidation of the molecular pathways regulated by PRKAR1A holds the promise of leading to molecularly designed therapies.

Research paper thumbnail of Throat Clearing — A Novel Asthma Symptom in Children

New England Journal of Medicine, 2003

Research paper thumbnail of Genetics of Carney Triad: Recurrent Losses at Chromosome 1 but Lack of Germline Mutations in Genes Associated with Paragangliomas and Gastrointestinal Stromal Tumors

Context: Carney triad (CT) describes the association of paragangliomas (PGLs) with gastrointestin... more Context: Carney triad (CT) describes the association of paragangliomas (PGLs) with gastrointestinal stromal tumors (GISTs) and pulmonary chondromas. Inactivating mutations of the mitochondrial complex II succinate dehydrogenase (SDH) enzyme subunits SDHB, SDHC, and SDHD are found in PGLs, gain-of-function mutations of c-kit (KIT), and platelet-derived growth factor receptor A (PDGFRA) in GISTs.

Research paper thumbnail of 17q22-24 Chromosomal Losses and Alterations of Protein Kinase A Subunit Expression and Activity in Adrenocorticotropin-Independent Macronodular Adrenal Hyperplasia

Primary adrenocortical hyperplasias leading to Cushing syndrome include primary pigmented nodular... more Primary adrenocortical hyperplasias leading to Cushing syndrome include primary pigmented nodular adrenocortical disease and ACTH-independent macronodular adrenal hyperplasia (AIMAH). Inactivating mutations of the 17q22-24-located PRKAR1A gene, coding for the type 1A regulatory subunit of protein kinase A (PKA), cause primary pigmented nodular adrenocortical disease and the multiple endocrine neoplasia syndrome Carney complex. PRKAR1A mutations and 17q22-24 chromosomal losses have been found in sporadic adrenal tumors and are associated with aberrant PKA signaling.

Research paper thumbnail of Adrenal Hyperplasia and Adenomas Are Associated with Inhibition of Phosphodiesterase 11A in Carriers of PDE11A Sequence Variants That Are Frequent in the Population

Several types of adrenocortical tumors that lead to Cushing syndrome may be caused by aberrant cy... more Several types of adrenocortical tumors that lead to Cushing syndrome may be caused by aberrant cyclic AMP (cAMP) signaling. We recently identified patients with micronodular adrenocortical hyperplasia who were carriers of inactivating mutations in the 2q-located phosphodiesterase 11A (PDE11A)

Research paper thumbnail of A cAMP-specific phosphodiesterase (PDE8B) that is mutated in adrenal hyperplasia is expressed widely in human and mouse tissues: a novel PDE8B isoform in human adrenal cortex

European Journal of Human Genetics, 2008

Bilateral adrenocortical hyperplasia (BAH) is the second most common cause of corticotropinindepe... more Bilateral adrenocortical hyperplasia (BAH) is the second most common cause of corticotropinindependent Cushing syndrome (CS). Genetic forms of BAH have been associated with complex syndromes such as Carney Complex and McCune Albright syndrome or may present as isolated micronodular adrenocortical disease (iMAD) usually in children and young adults with CS. A genome-wide association study identified inactivating phosphodiesterase (PDE) 11A (PDE11A) sequencing defects as low-penetrance predisposing factors for iMAD and related abnormalities; we also described a mutation (c.914A>C/H305P) in cAMP-specific PDE8B, in a patient with iMAD. In this study we further characterize this mutation; we also found a novel PDE8B isoform, highly expressed in the adrenal gland. This mutation is shown to significantly affect the ability of the protein to degrade cAMP in vitro. Tumor tissues from patients with iMAD and no mutations in the coding PDE8B sequence or any other related genes (PRKAR1A, PDE11A) showed down-regulated PDE8B expression (compared to normal adrenal cortex). Pde8b is detectable in the adrenal gland of newborn mice and is widely expressed in other mouse tissues. We conclude that PDE8B is another PDE gene linked to iMAD; it is a candidate causative gene for other adrenocortical lesions linked to the cAMPsignaling pathway, and possibly for tumors in other tissues.

Research paper thumbnail of Multiple Gastrointestinal Stromal and Other Tumors Caused by Platelet-Derived Growth Factor Receptor Gene Mutations: A Case Associated with a Germline V561D Defect

Research paper thumbnail of Mutations in Regulatory Subunit Type 1A of Cyclic Adenosine 5'-Monophosphate-Dependent Protein Kinase (PRKAR1A): Phenotype Analysis in 353 Patients and 80 Different Genotypes

Journal of Clinical Endocrinology & Metabolism, 2009

The &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;... more The &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;complex of myxomas, spotty skin pigmentation, and endocrine overactivity,&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; or &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;Carney complex&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; (CNC), is caused by inactivating mutations of the regulatory subunit type 1A of the cAMP-dependent protein kinase (PRKAR1A) gene and as yet unknown defect(s) in other gene(s). Delineation of a genotype-phenotype correlation for CNC patients is essential for understanding PRKAR1A function and providing counseling and preventive care.

Research paper thumbnail of Association of the M1V PRKAR1A Mutation with Primary Pigmented Nodular Adrenocortical Disease in Two Large Families

Journal of Clinical Endocrinology & Metabolism, 2010

Carney complex (CNC) is a familial multiple neoplasia syndrome frequently associated with primary... more Carney complex (CNC) is a familial multiple neoplasia syndrome frequently associated with primary pigmented nodular adrenocortical disease (PPNAD), a bilateral form of micronodular adrenal hyperplasia that leads to Cushing&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s syndrome (CS). Germline PRKAR1A mutations cause CNC and only rarely isolated PPNAD. PRKAR1A mutation analysis in two large families with CS and no other CNC manifestations demonstrated a M1V germline mutation; a total of 21 asymptomatic individuals were screened, and mutation carriers were evaluated for CNC. The mutation was expressed in vitro and functionally tested for its effects on protein kinase A function. Presymptomatic testing identified five first-degree relatives who were M1V carriers and who were all diagnosed with subclinical, mild CS at ages ranging from 20-56 yr. There were no other signs of CNC. In a cell-free system, we detected a shorter compared with the wild-type type 1alpha regulatory subunit of protein kinase A (PRKAR1A) protein (43 kDa). This was not identified in cell lines from the patients or in transfection experiments in HEK293 cells that showed no detectable PRKAR1A protein from the M1V-bearing constructs. In these cells, the mutant mRNA was expressed in a 1:1 ratio. In two large families, the M1V PRKAR1A mutation resulted in a PPNAD-only phenotype with significant variability both in terms of age of onset and clinical severity. Expression studies showed a unique effect of this sequence change. This study has implications for genetic counseling of carriers of this PRKAR1A mutation and patients with CNC and PPNAD and for the study of PRKAR1A-related tumorigenesis.

Research paper thumbnail of Differences in cortisol levels and body mass index between East Asians and Caucasians with Cushing's syndrome: an ?East Asian? phenotype for Cushing syndrome

Clinical Endocrinology, 2007

Research paper thumbnail of Adrenal Hyperplasia and Adenomas Are Associated with Inhibition of Phosphodiesterase 11A in Carriers of PDE11A Sequence Variants That Are Frequent in the Population

Cancer Research, 2006

Several types of adrenocortical tumors that lead to Cushing syndrome may be caused by aberrant cy... more Several types of adrenocortical tumors that lead to Cushing syndrome may be caused by aberrant cyclic AMP (cAMP) signaling. We recently identified patients with micronodular adrenocortical hyperplasia who were carriers of inactivating mutations in the 2q-located phosphodiesterase 11A (PDE11A) gene. We now studied the frequency of two missense substitutions, R804H and R867G, in conserved regions of the enzyme in several sets of normal controls, including 745 individuals enrolled in a longitudinal cohort study, the New York Cancer Project. In the latter, we also screened for the presence of the previously identified PDE11A nonsense mutations. R804H and R867G were frequent among patients with adrenocortical tumors; although statistical significance was not reached, these variants affected significantly enzymatic function in vitro with variable increases in cAMP and/or cyclic guanosine 3 ¶,5 ¶-monophosphate levels in HeLa and HEK293 cells. Adrenocortical tissues carrying the R804H mutation showed 2q allelic losses and higher cyclic nucleotide levels and cAMP-responsive element binding protein phosphorylation. We conclude that missense mutations of the PDE11A gene that affect enzymatic activity in vitro are present in the general population; protein-truncating PDE11A mutations may also contribute to a predisposition to other tumors, in addition to their association with adrenocortical hyperplasia. We speculate that PDE11A genetic defects may be associated with adrenal pathology in a wider than previously suspected clinical spectrum that includes asymptomatic individuals. (Cancer Res 2006; 66(24): 11571-5)

Research paper thumbnail of Polymorphisms of the Vitamin D Receptor Gene and Stress Fractures

Hormone and Metabolic Research, 2009

Our aim was to evaluate the association between VDR polymorphisms and calcaneal Stiffness Index (... more Our aim was to evaluate the association between VDR polymorphisms and calcaneal Stiffness Index (SI) with stress fractures in a case control study including male military personnel. Thirtytwo patients with stress fractures were matched with 32 uninjured healthy volunteers (controls), by gender, age, height, body weight, and level of physical activity. The two groups were genotyped for the FokI, BsmI, ApaI, and TaqI polymorphisms of the VDR gene with PCR-RFLP method. In addition, calcaneal SI was measured by heel quantitative ultrasound in both groups. Data were analyzed by chi-squared test and logistic regression analysis. The f allele was significantly more frequent in patients than in controls (p=0.013), while the B allele showed such a tendency without reaching statistical significance (p=0.052). Among the entire cohort, a 2.7-fold and a 2.0-fold increase in risk of stress fractures was associated with the f and B alleles (OR, 2.7, 95% CI, 1.2-5.9; p=0.014 and OR, 2.0, 95% CI, 1.0-4.1; p=0.053, respectively). No statistically significant association was found between the incidence of stress fractures and t or a alleles. Decreased Tscores were also associated with the presence of f and B alleles. Mean values of T-scores of SI were statistically significantly lower in patients than in controls (p=0.018). These results suggest that the FokI and BsmI polymorphisms of the VDR gene could be associated with increased risk of stress fractures among military personnel. Moreover, a low calcaneal SI could represent a measurable index of this increased risk.

Research paper thumbnail of Mouse Prkar1a haploinsufficiency leads to an increase in tumors in the Trp53+/- or Rb1+/- backgrounds and chemically induced skin papillomas by dysregulation of the cell cycle and Wnt signaling

Human Molecular Genetics, 2010

PRKAR1A inactivation leads to dysregulated cAMP signaling and Carney complex (CNC) in humans, a s... more PRKAR1A inactivation leads to dysregulated cAMP signaling and Carney complex (CNC) in humans, a syndrome associated with skin, endocrine and other tumors. The CNC phenotype is not easily explained by the ubiquitous cAMP signaling defect; furthermore, Prkar1a 1/ 2 mice did not develop skin and other CNC tumors. To identify whether a Prkar1a defect is truly a generic but weak tumorigenic signal that depends on tissue-specific or other factors, we investigated Prkar1a 1/2 mice when bred within the Rb1 1/2 or Trp53 1/2 backgrounds, or treated with a two-step skin carcinogenesis protocol. Prkar1a 1/2 Trp53 1/2 mice developed more sarcomas than Trp53 1/2 mice (P < 0.05) and Prkar1a 1/2 Rb1 1/2 mice grew more (and larger) pituitary and thyroid tumors than Rb1 1/2 mice. All mice with double heterozygosity had significantly reduced life-spans compared with their single-heterozygous counterparts. Prkar1a 1/2 mice also developed more papillomas than wild-type animals. A whole-genome transcriptome profiling of tumors produced by all three models identified Wnt signaling as the main pathway activated by abnormal cAMP signaling, along with cell cycle abnormalities; all changes were confirmed by qRT -PCR array and immunohistochemistry. siRNA down-regulation of Ctnnb1, E2f1 or Cdk4 inhibited proliferation of human adrenal cells bearing a PRKAR1A-inactivating mutation and Prkar1a 1/2 mouse embryonic fibroblasts and arrested both cell lines at the G0/G1 phase of the cell cycle.

Research paper thumbnail of Multiple Gastrointestinal Stromal and Other Tumors Caused by Platelet-Derived Growth Factor Receptor Gene Mutations: A Case Associated with a Germline V561D Defect

Journal of Clinical Endocrinology & Metabolism, 2007

Research paper thumbnail of Novel polymorphisms and lack of mutations in the ACD gene in patients with ACTH resistance syndromes

Clinical Endocrinology, 2007

Objective ACTH resistance is a feature of several human syndromes with known genetic causes, inc... more Objective ACTH resistance is a feature of several human syndromes with known genetic causes, including familial glucocorticoid deficiency (types 1 and 2) and triple A syndrome. However, many patients with ACTH resistance lack an identifiable genetic aetiology. The human homolog of the Acd gene, mutated in a mouse model of adrenal insufficiency, was sequenced in 25 patients with a clinical diagnosis of familial glucocorticoid deficiency or triple A syndrome.Design A 3·4 kilobase genomic fragment containing the entire ACD gene was analysed for mutations in all 25 patients.Setting Samples were obtained by three investigators from different institutions.Patients The primary cohort consisted of 25 unrelated patients, primarily of European or Middle Eastern descent, with a clinical diagnosis of either familial glucocorticoid deficiency (FGD) or triple A syndrome. Patients lacked mutations in other genes known to cause ACTH resistance, including AAAS for patients diagnosed with triple A syndrome and MC2R and MRAP for patients diagnosed with familial glucocorticoid deficiency. Thirty-five additional patients with adrenal disease phenotypes were added to form an expanded cohort of 60 patients.Measurements Identification of DNA sequence changes in the ACD gene in the primary cohort and analysis of putative ACD haplotypes in the expanded cohort.Results No disease-causing mutations were found, but several novel single nucleotide polymorphisms (SNPs) and two putative haplotypes were identified. The overall frequency of SNPs in ACD is low compared to other gene families.Conclusions No mutations were identified in ACD in this collection of patients with ACTH resistance phenotypes. However, the newly identified SNPs in ACD should be more closely examined for possible links to disease.