Luigi Bisceglia - Academia.edu (original) (raw)

Papers by Luigi Bisceglia

Research paper thumbnail of BMC_Research_Notes_Bianco_A_et_al_Methods.docx

Detailed Methodology for BMC Research Notes paper by Bianco A. et al.

Research paper thumbnail of Data Set 2.xlsx

Collection of 52 Spanish subjects with a LHON-causing mutation in homoplasmy and 28 control subje... more Collection of 52 Spanish subjects with a LHON-causing mutation in homoplasmy and 28 control subjects.<br>

Research paper thumbnail of Data Set 1.xlsx

Collection of clinical and molecular data of 46 Italian subjects with a LHON-causing mutation in ... more Collection of clinical and molecular data of 46 Italian subjects with a LHON-causing mutation in homoplasmy and 90 control subjects.<br>

Research paper thumbnail of Human gene mutations. Gene symbol: SLC3A1. Disease: cystinuria

Research paper thumbnail of © 2011 Molecular Vision Mutational screening of VSX1, SPARC, SOD1, LOX, and TIMP3 in keratoconus

Purpose: To evaluate the involvement of Visual System Homeobox 1 (VSX1), Secreted Protein Acidic ... more Purpose: To evaluate the involvement of Visual System Homeobox 1 (VSX1), Secreted Protein Acidic and Rich in

Research paper thumbnail of Genetic variant of C1GalT1 contributes to the susceptibility to IgA nephropathy

Journal of nephrology, 2009

BACKGROUND IgA nephropathy (IgAN) is a common form of primary glomerulonephritis characterized by... more BACKGROUND IgA nephropathy (IgAN) is a common form of primary glomerulonephritis characterized by diffuse glomerular mesangial IgA1 deposition that leads to mesangial proliferation and chronic glomerular inflammation. Analyses of serum IgA1 from IgAN patients revealed an abnormal galactosylation of the O-linked carbohydrate moieties of IgA that may be a result of altered activity of core 1 beta1,3-galactosyltransferase (C1GalT1). To evaluate the association between C1GalT1 single nucleotide polymorphisms (SNPs) and IgAN, we performed a case control study on cohorts from the Italian population. METHODS We sequenced C1GalT1 coding and promoter regions in 284 IgAN patients and 210 healthy controls. The functional role of 3' untranslated region (3'UTR) SNPs was studied using electrophoretic mobility shift assays and real-time quantitative PCR. RESULTS We analyzed 8 SNPs in the C1GalT1 gene: 5 SNPs were in the promoter region and 3 SNPs in the 3'UTR. The allele 1365G in the 3...

Research paper thumbnail of A mutation in the iron responsive element of ferritin L-subunit gene is associated with the recently described ''hereditary hyperferritinemia-cataract syndrome

Research paper thumbnail of Novel human pathological mutations. Gene symbol: SLC3A1. Disease: cystinuria

Human genetics, 2010

... Gene symbol: MECP2. Disease: Rett Syndrome. Khajuria R, Sapra S, Ghosh M, Gupta N,Gulati S, K... more ... Gene symbol: MECP2. Disease: Rett Syndrome. Khajuria R, Sapra S, Ghosh M, Gupta N,Gulati S, Kalra V, Kabra M. Genetics Unit, Department of Pediatrics, All India Institute of Medical Sciences, 110029, New Delhi, India. rajni.khajuria@gmail.com. ...

Research paper thumbnail of Leber's hereditary optic neuropathy (LHON) in an Apulian cohort of subjects

Acta myologica : myopathies and cardiomyopathies : official journal of the Mediterranean Society of Myology, 2017

Leber's hereditary optic neuropathy (LHON) is a maternally inherited disorder that causes sev... more Leber's hereditary optic neuropathy (LHON) is a maternally inherited disorder that causes severe loss of sight in young adults, and is typically associated to mitochondrial DNA (mtDNA) mutations. Heteroplasmy of primary LHON mutations, presence of 'ancillary' mtDNA mutations, and mtDNA copy number are probably correlated with the penetrance and the severity of the disease. In this study, we performed a mutational screening in an Apulian cohort of LHON patients and we found that 41 out of 54 subjects harbored the m.11778G>A mutation, and 13 harbored the m.3460G>A mutation. Whole mtDNA sequencing was performed in three affected subjects belonging to three unrelated m.11778G>A pedigrees to evaluate the putative synergistic role of additional mtDNA mutations in determining the phenotype. Our study suggests to include haplogroup T as a possible genetic background influencing LHON penetrance and to consider the increase of mtDNA copy number as a protective factor from...

Research paper thumbnail of Resequencing of candidate genes for Keratoconus reveals a role for Ehlers–Danlos Syndrome genes

European Journal of Human Genetics

The involvement of genetic factors in the pathogenesis of KC has long been recognized but the ide... more The involvement of genetic factors in the pathogenesis of KC has long been recognized but the identification of variants affecting the underlying protein functions has been challenging. In this study, we selected 34 candidate genes for KC based on previous whole-exome sequencing (WES) and the literature, and resequenced them in 745 KC patients and 810 ethnically matched controls from Belgium, France and Italy. Data analysis was performed using the single variant association test as well as gene-based mutation burden and variance components tests. In our study, we detected enrichment of genetic variation across multiple gene-based tests for the genes COL2A1, COL5A1, TNXB, and ZNF469. The top hit in the single variant association test was obtained for a common variant in the COL12A1 gene. These associations were consistently found across independent subpopulations. Interestingly, COL5A1, TNXB, ZNF469 and COL12A1 are all known Ehlers-Danlos Syndrome (EDS) genes. Though the co-occurrence of KC and EDS has been reported previously, this study is the first to demonstrate a consistent role of genetic variants in EDS genes in the etiology of KC. In conclusion, our data show a shared genetic etiology between KC and EDS, and clearly confirm the currently disputed role of ZNF469 in disease susceptibility for KC.

Research paper thumbnail of Novel TONSL variants cause SPONASTRIME dysplasia and associate with spontaneous chromosome breaks, defective cell proliferation and apoptosis

Human Molecular Genetics

SPONASTRIME dysplasia is an ultrarare spondyloepimetaphyseal dysplasia featuring short stature an... more SPONASTRIME dysplasia is an ultrarare spondyloepimetaphyseal dysplasia featuring short stature and short limbs, platyspondyly, depressed nasal bridge with midface hypoplasia and striated metaphyses. In 2019, an autosomal recessive inheritance was demonstrated by the identification of bi-allelic hypomorphic alleles in TONSL. The encoded protein has a critical role in maintaining genome integrity by promoting the homologous recombination required for repairing spontaneous replication-associated DNA lesions at collapsed replication forks. We report a 9-year-old girl with typical SPONASTRIME dysplasia and resulted in carrier of the novel missense p.(Gln430Arg) and p.(Leu1090Arg) variants in TONSL at whole-exome sequencing. In silico analysis predicted that these variants induced thermodynamic changes with a pathogenic impact on protein function. To support the pathogenicity of the identified variants, cytogenetic analysis and microscopy assays showed that patient-derived fibroblasts exh...

Research paper thumbnail of Compound Phenotype Due to Recessive Variants in LARP7 and OTOG Genes Disclosed by an Integrated Approach of SNP-Array and Whole Exome Sequencing

Genes, Mar 31, 2020

Neurodevelopmental disorders are a challenge in medical genetics due to genetic heterogeneity and... more Neurodevelopmental disorders are a challenge in medical genetics due to genetic heterogeneity and complex genotype-phenotype correlations. For this reason, the resolution of single cases not belonging to well-defined syndromes often requires an integrated approach of multiple whole-genome technologies. Such an approach has also unexpectedly revealed a complex molecular basis in an increasing number of patients, for whom the original suspect of a pleiotropic syndrome has been resolved as the summation effect of multiple genes. We describe a 10-year-old boy, the third son of first-cousin parents, with global developmental delay, facial dysmorphism, and bilateral deafness. SNP-array analysis revealed regions of homozygosity (ROHs) in multiple chromosome regions. Whole-exome sequencing prioritized on gene-mapping into the ROHs showed homozygosity for the likely pathogenic c.1097_1098delAG p. (Arg366Thrfs*2) frameshift substitution in LARP7 and the likely pathogenic c.5743C>T p.(Arg1915*) nonsense variant in OTOG. Recessive variants in LARP7 cause Alazami syndrome, while variants in OTOG cause an extremely rare autosomal recessive form of neurosensorial deafness. Previously unreported features were acrocyanosis and palmoplantar hyperhidrosis. This case highlights the utility of encouraging technological updates in medical genetics laboratories involved in the study of neurodevelopmental disorders and integrating laboratory outputs with the competencies of next-generation clinicians.

Research paper thumbnail of Mitochondrial DNA copy number in affected and unaffected LHON mutation carriers

BMC Research Notes

Objectives: Leber's hereditary optic neuropathy (LHON) is a mitochondrial genetic disease charact... more Objectives: Leber's hereditary optic neuropathy (LHON) is a mitochondrial genetic disease characterized by a variable and reduced penetrance. Individuals carrying a primary LHON-causing mitochondrial DNA (mtDNA) mutation may either remain asymptomatic lifelong, as unaffected carriers, or develop sudden central visual loss that rapidly aggravates over some weeks. Over the years several genetic/environmental triggers able to modulate the risk of developing LHON have been proposed. We provided data supporting a possible correlation between LHON penetrance and the mtDNA copy number, a raw index of mitochondrial mass, whose increase could represent a compensatory response that cells implement to alleviate the pathogenic effect of the primary LHON-causing mtDNA mutations. Data description: We collected Italian and Spanish subjects harboring one of the three common LHON primary mutations, either in heteroplasmic or homoplasmic status. For each population we were able to discriminate between affected subjects presenting typical clinical tracts of LHON and LHON-causing mutation carriers showing no symptoms correlated with vision loss. Each subject has been characterized for the presence of a LHON primary mutation, for its status of homoplasmy or heteroplasmy, and for the mtDNA content per cell, expressed as relative mtDNA/ nDNA ratio respect to controls. Additional clinical information is present for all the Italian subjects.

Research paper thumbnail of Mitochondrial DNA copy number in affected and unaffected LHON mutation carriers

BMC Research Notes, 2018

Objectives: Leber's hereditary optic neuropathy (LHON) is a mitochondrial genetic disease cha... more Objectives: Leber's hereditary optic neuropathy (LHON) is a mitochondrial genetic disease characterized by a variable and reduced penetrance. Individuals carrying a primary LHON-causing mitochondrial DNA (mtDNA) mutation may either remain asymptomatic lifelong, as unaffected carriers, or develop sudden central visual loss that rapidly aggravates over some weeks. Over the years several genetic/environmental triggers able to modulate the risk of developing LHON have been proposed. We provided data supporting a possible correlation between LHON pen-etrance and the mtDNA copy number, a raw index of mitochondrial mass, whose increase could represent a compensatory response that cells implement to alleviate the pathogenic effect of the primary LHON-causing mtDNA mutations. Data description: We collected Italian and Spanish subjects harboring one of the three common LHON primary mutations, either in heteroplasmic or homoplasmic status. For each population we were able to discriminate b...

Research paper thumbnail of Leber's hereditary optic neuropathy, intellectual disability and epilepsy presenting with variable penetrance associated to the m.3460G >A mutation and a heteroplasmic expansion of the microsatellite in MTRNR1 gene - case report

BMC medical genetics, Jan 27, 2018

Leber's hereditary optic neuropathy (LHON) associated with mutations in mitochondrial DNA (mt... more Leber's hereditary optic neuropathy (LHON) associated with mutations in mitochondrial DNA (mtDNA) typically manifests only optic nerve involvement but in some patients may develop additional neurological complications. The cause of this association is not clear. We present a case of a 24-year-old male with a history of subacute, painless, and rapidly progressive bilateral vision loss. We performed ophthalmological, neurological and neuropsychological investigations in the proband and his LHON family. The proband showed optic neuropathy, epilepsy, migraine, and intellectual disability; all the maternal relatives did not manifest optic neuropathy but a moderate to severe intellectual disability. Genetic screening revealed a novel association of the LHON m.3460G > A primary mutation with the m.T961delT + C(n)ins within the mitochondrial encoded 12S RNA (MTRNR1) gene which segregates with the intellectual disability through the maternal branch of the family. We also found a signi...

Research paper thumbnail of A single-center study on 140 patients with cerebral cavernous malformations: 28 new pathogenic variants and functional characterization of a PDCD10 large deletion ​

Human mutation, Jan 30, 2018

Cerebral cavernous malformation (CCM) is a capillary malformation arising in the central nervous ... more Cerebral cavernous malformation (CCM) is a capillary malformation arising in the central nervous system. CCM may occur sporadically or cluster in families with autosomal dominant transmission, incomplete penetrance and variable expressivity. Three genes are associated with CCM KRIT1, CCM2 and PDCD10. This work is a retrospective single-centre molecular study on samples from multiple Italian clinical providers. From a pool of 317 CCM index patients we found germline variants in either of the three genes in 80 (25.2%) probands, for a total of 55 different variants. In available families, extended molecular analysis found segregation in 60 additional subjects, for a total of 140 mutated individuals. From the 55 variants, 39 occurred in KRIT1 (20 novel), 8 in CCM2 (4 novel) and 8 in PDCD10 (4 novel). Effects of the 3 novel KRIT1 missense variants were characterized in silico. We also investigated a novel PDCD10 deletion spanning exon 4-10, on patient's fibroblasts, which showed sign...

Research paper thumbnail of A novel mutation in CDH11, encoding cadherin-11, cause Branchioskeletogenital (Elsahy-Waters) syndrome

American journal of medical genetics. Part A, Jan 8, 2018

Cadherins are cell-adhesion molecules that control morphogenesis, cell migration, and cell shape ... more Cadherins are cell-adhesion molecules that control morphogenesis, cell migration, and cell shape changes during multiple developmental processes. Until now four distinct cadherins have been implicated in human Mendelian disorders, mainly featuring skin, retinal and hearing manifestations. Branchio-skeleto-genital (or Elsahy-Waters) syndrome (BSGS) is an ultra-rare condition featuring a characteristic face, premature loss of teeth, vertebral and genital anomalies, and intellectual disability. We have studied two sibs with BSGS originally described by Castori et al. in 2010. Exome sequencing led to the identification of a novel homozygous nonsense variant in the first exon of the cadherin-11 gene (CDH11), which results in a prematurely truncated form of the protein. Recessive variants in CDH11 have been recently demonstrated in two other sporadic patients and a pair of sisters affected by BSGS. Although the function of this cadherin (also termed Osteoblast-Cadherin) is not completely ...

Research paper thumbnail of Leber's hereditary optic neuropathy (LHON) in an Apulian cohort of subjects

Acta myologica : myopathies and cardiomyopathies : official journal of the Mediterranean Society of Myology, 2017

Leber's hereditary optic neuropathy (LHON) is a maternally inherited disorder that causes sev... more Leber's hereditary optic neuropathy (LHON) is a maternally inherited disorder that causes severe loss of sight in young adults, and is typically associated to mitochondrial DNA (mtDNA) mutations. Heteroplasmy of primary LHON mutations, presence of 'ancillary' mtDNA mutations, and mtDNA copy number are probably correlated with the penetrance and the severity of the disease. In this study, we performed a mutational screening in an Apulian cohort of LHON patients and we found that 41 out of 54 subjects harbored the m.11778G>A mutation, and 13 harbored the m.3460G>A mutation. Whole mtDNA sequencing was performed in three affected subjects belonging to three unrelated m.11778G>A pedigrees to evaluate the putative synergistic role of additional mtDNA mutations in determining the phenotype. Our study suggests to include haplogroup T as a possible genetic background influencing LHON penetrance and to consider the increase of mtDNA copy number as a protective factor from...

Research paper thumbnail of High Mitochondrial DNA Copy Number Is a Protective Factor From Vision Loss in Heteroplasmic Leber's Hereditary Optic Neuropathy (LHON)

Investigative Opthalmology & Visual Science, 2017

PURPOSE. Leber's hereditary optic neuropathy (LHON) is a mitochondrial disease that typically cau... more PURPOSE. Leber's hereditary optic neuropathy (LHON) is a mitochondrial disease that typically causes bilateral blindness in young men. It is characterized by as yet undisclosed genetic and environmental factors affecting the incomplete penetrance. METHODS. We identified 27 LHON subjects who possess heteroplasmic primary LHON mutations. Mitochondrial DNA (mtDNA) copy number was evaluated. RESULTS. The presence of centrocecal scotoma, an edematous, hyperemic optic nerve head, and vascular tortuosity, as well as telangiectasia was recognized in affected subjects. We found higher cellular mtDNA content in peripheral blood cells of unaffected heteroplasmic mutation carriers with respect to the affected. CONCLUSIONS. The increase of cellular mtDNA content prevents complete loss of vision despite the presence of a heteroplasmic state of LHON primary mutation, suggesting that it is a key factor responsible for penetrance of LHON.

Research paper thumbnail of Expanding the mutation spectrum in 130 probands with ARPKD: identification of 62 novel PKHD1 mutations by sanger sequencing and MLPA analysis

Journal of Human Genetics, 2016

Autosomal recessive polycystic kidney disease (ARPKD) is a rare severe genetic disorder arising i... more Autosomal recessive polycystic kidney disease (ARPKD) is a rare severe genetic disorder arising in the perinatal period, although a late-onset presentation of the disease has been described. Pulmonary hypoplasia is the major cause of morbidity and mortality in the newborn period. ARPKD is caused by mutations in the PKHD1 (polycystic kidney and hepatic disease 1) gene that is among the largest human genes. To achieve a molecular diagnosis of the disease, a large series of Italian affected subjects were recruited. Exhaustive mutation analysis of PKHD1 gene was carried out by Sanger sequencing and multiple ligation probe amplification (MLPA) technique in 110 individuals. A total of 173 mutations resulting in a detection rate of 78.6% were identified. Additional 20 unrelated patients, in whom it was not possible to analyze the whole coding sequence, have been included in this study. Taking into account the total number (n = 130) of this cohort of patients, 107 different types of mutations have been detected in 193 mutated alleles. Out of 107 mutations, 62 were novel: 11 nonsense, 6 frameshift, 7 splice site mutations, 2 in-frame deletions and 2 multiexon deletion detected by MLPA. Thirty-four were missense variants. In conclusion, our report expands the spectrum of PKHD1 mutations and confirms the heterogeneity of this disorder. The population under study represents the largest Italian ARPKD cohort reported to date. The estimated costs and the time invested for molecular screening of genes with large size and allelic heterogeneity such as PKHD1 demand the use of next-generation sequencing (NGS) technologies for a faster and cheaper screening of the affected subjects.

Research paper thumbnail of BMC_Research_Notes_Bianco_A_et_al_Methods.docx

Detailed Methodology for BMC Research Notes paper by Bianco A. et al.

Research paper thumbnail of Data Set 2.xlsx

Collection of 52 Spanish subjects with a LHON-causing mutation in homoplasmy and 28 control subje... more Collection of 52 Spanish subjects with a LHON-causing mutation in homoplasmy and 28 control subjects.<br>

Research paper thumbnail of Data Set 1.xlsx

Collection of clinical and molecular data of 46 Italian subjects with a LHON-causing mutation in ... more Collection of clinical and molecular data of 46 Italian subjects with a LHON-causing mutation in homoplasmy and 90 control subjects.<br>

Research paper thumbnail of Human gene mutations. Gene symbol: SLC3A1. Disease: cystinuria

Research paper thumbnail of © 2011 Molecular Vision Mutational screening of VSX1, SPARC, SOD1, LOX, and TIMP3 in keratoconus

Purpose: To evaluate the involvement of Visual System Homeobox 1 (VSX1), Secreted Protein Acidic ... more Purpose: To evaluate the involvement of Visual System Homeobox 1 (VSX1), Secreted Protein Acidic and Rich in

Research paper thumbnail of Genetic variant of C1GalT1 contributes to the susceptibility to IgA nephropathy

Journal of nephrology, 2009

BACKGROUND IgA nephropathy (IgAN) is a common form of primary glomerulonephritis characterized by... more BACKGROUND IgA nephropathy (IgAN) is a common form of primary glomerulonephritis characterized by diffuse glomerular mesangial IgA1 deposition that leads to mesangial proliferation and chronic glomerular inflammation. Analyses of serum IgA1 from IgAN patients revealed an abnormal galactosylation of the O-linked carbohydrate moieties of IgA that may be a result of altered activity of core 1 beta1,3-galactosyltransferase (C1GalT1). To evaluate the association between C1GalT1 single nucleotide polymorphisms (SNPs) and IgAN, we performed a case control study on cohorts from the Italian population. METHODS We sequenced C1GalT1 coding and promoter regions in 284 IgAN patients and 210 healthy controls. The functional role of 3' untranslated region (3'UTR) SNPs was studied using electrophoretic mobility shift assays and real-time quantitative PCR. RESULTS We analyzed 8 SNPs in the C1GalT1 gene: 5 SNPs were in the promoter region and 3 SNPs in the 3'UTR. The allele 1365G in the 3...

Research paper thumbnail of A mutation in the iron responsive element of ferritin L-subunit gene is associated with the recently described ''hereditary hyperferritinemia-cataract syndrome

Research paper thumbnail of Novel human pathological mutations. Gene symbol: SLC3A1. Disease: cystinuria

Human genetics, 2010

... Gene symbol: MECP2. Disease: Rett Syndrome. Khajuria R, Sapra S, Ghosh M, Gupta N,Gulati S, K... more ... Gene symbol: MECP2. Disease: Rett Syndrome. Khajuria R, Sapra S, Ghosh M, Gupta N,Gulati S, Kalra V, Kabra M. Genetics Unit, Department of Pediatrics, All India Institute of Medical Sciences, 110029, New Delhi, India. rajni.khajuria@gmail.com. ...

Research paper thumbnail of Leber's hereditary optic neuropathy (LHON) in an Apulian cohort of subjects

Acta myologica : myopathies and cardiomyopathies : official journal of the Mediterranean Society of Myology, 2017

Leber's hereditary optic neuropathy (LHON) is a maternally inherited disorder that causes sev... more Leber's hereditary optic neuropathy (LHON) is a maternally inherited disorder that causes severe loss of sight in young adults, and is typically associated to mitochondrial DNA (mtDNA) mutations. Heteroplasmy of primary LHON mutations, presence of 'ancillary' mtDNA mutations, and mtDNA copy number are probably correlated with the penetrance and the severity of the disease. In this study, we performed a mutational screening in an Apulian cohort of LHON patients and we found that 41 out of 54 subjects harbored the m.11778G>A mutation, and 13 harbored the m.3460G>A mutation. Whole mtDNA sequencing was performed in three affected subjects belonging to three unrelated m.11778G>A pedigrees to evaluate the putative synergistic role of additional mtDNA mutations in determining the phenotype. Our study suggests to include haplogroup T as a possible genetic background influencing LHON penetrance and to consider the increase of mtDNA copy number as a protective factor from...

Research paper thumbnail of Resequencing of candidate genes for Keratoconus reveals a role for Ehlers–Danlos Syndrome genes

European Journal of Human Genetics

The involvement of genetic factors in the pathogenesis of KC has long been recognized but the ide... more The involvement of genetic factors in the pathogenesis of KC has long been recognized but the identification of variants affecting the underlying protein functions has been challenging. In this study, we selected 34 candidate genes for KC based on previous whole-exome sequencing (WES) and the literature, and resequenced them in 745 KC patients and 810 ethnically matched controls from Belgium, France and Italy. Data analysis was performed using the single variant association test as well as gene-based mutation burden and variance components tests. In our study, we detected enrichment of genetic variation across multiple gene-based tests for the genes COL2A1, COL5A1, TNXB, and ZNF469. The top hit in the single variant association test was obtained for a common variant in the COL12A1 gene. These associations were consistently found across independent subpopulations. Interestingly, COL5A1, TNXB, ZNF469 and COL12A1 are all known Ehlers-Danlos Syndrome (EDS) genes. Though the co-occurrence of KC and EDS has been reported previously, this study is the first to demonstrate a consistent role of genetic variants in EDS genes in the etiology of KC. In conclusion, our data show a shared genetic etiology between KC and EDS, and clearly confirm the currently disputed role of ZNF469 in disease susceptibility for KC.

Research paper thumbnail of Novel TONSL variants cause SPONASTRIME dysplasia and associate with spontaneous chromosome breaks, defective cell proliferation and apoptosis

Human Molecular Genetics

SPONASTRIME dysplasia is an ultrarare spondyloepimetaphyseal dysplasia featuring short stature an... more SPONASTRIME dysplasia is an ultrarare spondyloepimetaphyseal dysplasia featuring short stature and short limbs, platyspondyly, depressed nasal bridge with midface hypoplasia and striated metaphyses. In 2019, an autosomal recessive inheritance was demonstrated by the identification of bi-allelic hypomorphic alleles in TONSL. The encoded protein has a critical role in maintaining genome integrity by promoting the homologous recombination required for repairing spontaneous replication-associated DNA lesions at collapsed replication forks. We report a 9-year-old girl with typical SPONASTRIME dysplasia and resulted in carrier of the novel missense p.(Gln430Arg) and p.(Leu1090Arg) variants in TONSL at whole-exome sequencing. In silico analysis predicted that these variants induced thermodynamic changes with a pathogenic impact on protein function. To support the pathogenicity of the identified variants, cytogenetic analysis and microscopy assays showed that patient-derived fibroblasts exh...

Research paper thumbnail of Compound Phenotype Due to Recessive Variants in LARP7 and OTOG Genes Disclosed by an Integrated Approach of SNP-Array and Whole Exome Sequencing

Genes, Mar 31, 2020

Neurodevelopmental disorders are a challenge in medical genetics due to genetic heterogeneity and... more Neurodevelopmental disorders are a challenge in medical genetics due to genetic heterogeneity and complex genotype-phenotype correlations. For this reason, the resolution of single cases not belonging to well-defined syndromes often requires an integrated approach of multiple whole-genome technologies. Such an approach has also unexpectedly revealed a complex molecular basis in an increasing number of patients, for whom the original suspect of a pleiotropic syndrome has been resolved as the summation effect of multiple genes. We describe a 10-year-old boy, the third son of first-cousin parents, with global developmental delay, facial dysmorphism, and bilateral deafness. SNP-array analysis revealed regions of homozygosity (ROHs) in multiple chromosome regions. Whole-exome sequencing prioritized on gene-mapping into the ROHs showed homozygosity for the likely pathogenic c.1097_1098delAG p. (Arg366Thrfs*2) frameshift substitution in LARP7 and the likely pathogenic c.5743C>T p.(Arg1915*) nonsense variant in OTOG. Recessive variants in LARP7 cause Alazami syndrome, while variants in OTOG cause an extremely rare autosomal recessive form of neurosensorial deafness. Previously unreported features were acrocyanosis and palmoplantar hyperhidrosis. This case highlights the utility of encouraging technological updates in medical genetics laboratories involved in the study of neurodevelopmental disorders and integrating laboratory outputs with the competencies of next-generation clinicians.

Research paper thumbnail of Mitochondrial DNA copy number in affected and unaffected LHON mutation carriers

BMC Research Notes

Objectives: Leber's hereditary optic neuropathy (LHON) is a mitochondrial genetic disease charact... more Objectives: Leber's hereditary optic neuropathy (LHON) is a mitochondrial genetic disease characterized by a variable and reduced penetrance. Individuals carrying a primary LHON-causing mitochondrial DNA (mtDNA) mutation may either remain asymptomatic lifelong, as unaffected carriers, or develop sudden central visual loss that rapidly aggravates over some weeks. Over the years several genetic/environmental triggers able to modulate the risk of developing LHON have been proposed. We provided data supporting a possible correlation between LHON penetrance and the mtDNA copy number, a raw index of mitochondrial mass, whose increase could represent a compensatory response that cells implement to alleviate the pathogenic effect of the primary LHON-causing mtDNA mutations. Data description: We collected Italian and Spanish subjects harboring one of the three common LHON primary mutations, either in heteroplasmic or homoplasmic status. For each population we were able to discriminate between affected subjects presenting typical clinical tracts of LHON and LHON-causing mutation carriers showing no symptoms correlated with vision loss. Each subject has been characterized for the presence of a LHON primary mutation, for its status of homoplasmy or heteroplasmy, and for the mtDNA content per cell, expressed as relative mtDNA/ nDNA ratio respect to controls. Additional clinical information is present for all the Italian subjects.

Research paper thumbnail of Mitochondrial DNA copy number in affected and unaffected LHON mutation carriers

BMC Research Notes, 2018

Objectives: Leber's hereditary optic neuropathy (LHON) is a mitochondrial genetic disease cha... more Objectives: Leber's hereditary optic neuropathy (LHON) is a mitochondrial genetic disease characterized by a variable and reduced penetrance. Individuals carrying a primary LHON-causing mitochondrial DNA (mtDNA) mutation may either remain asymptomatic lifelong, as unaffected carriers, or develop sudden central visual loss that rapidly aggravates over some weeks. Over the years several genetic/environmental triggers able to modulate the risk of developing LHON have been proposed. We provided data supporting a possible correlation between LHON pen-etrance and the mtDNA copy number, a raw index of mitochondrial mass, whose increase could represent a compensatory response that cells implement to alleviate the pathogenic effect of the primary LHON-causing mtDNA mutations. Data description: We collected Italian and Spanish subjects harboring one of the three common LHON primary mutations, either in heteroplasmic or homoplasmic status. For each population we were able to discriminate b...

Research paper thumbnail of Leber's hereditary optic neuropathy, intellectual disability and epilepsy presenting with variable penetrance associated to the m.3460G >A mutation and a heteroplasmic expansion of the microsatellite in MTRNR1 gene - case report

BMC medical genetics, Jan 27, 2018

Leber's hereditary optic neuropathy (LHON) associated with mutations in mitochondrial DNA (mt... more Leber's hereditary optic neuropathy (LHON) associated with mutations in mitochondrial DNA (mtDNA) typically manifests only optic nerve involvement but in some patients may develop additional neurological complications. The cause of this association is not clear. We present a case of a 24-year-old male with a history of subacute, painless, and rapidly progressive bilateral vision loss. We performed ophthalmological, neurological and neuropsychological investigations in the proband and his LHON family. The proband showed optic neuropathy, epilepsy, migraine, and intellectual disability; all the maternal relatives did not manifest optic neuropathy but a moderate to severe intellectual disability. Genetic screening revealed a novel association of the LHON m.3460G > A primary mutation with the m.T961delT + C(n)ins within the mitochondrial encoded 12S RNA (MTRNR1) gene which segregates with the intellectual disability through the maternal branch of the family. We also found a signi...

Research paper thumbnail of A single-center study on 140 patients with cerebral cavernous malformations: 28 new pathogenic variants and functional characterization of a PDCD10 large deletion ​

Human mutation, Jan 30, 2018

Cerebral cavernous malformation (CCM) is a capillary malformation arising in the central nervous ... more Cerebral cavernous malformation (CCM) is a capillary malformation arising in the central nervous system. CCM may occur sporadically or cluster in families with autosomal dominant transmission, incomplete penetrance and variable expressivity. Three genes are associated with CCM KRIT1, CCM2 and PDCD10. This work is a retrospective single-centre molecular study on samples from multiple Italian clinical providers. From a pool of 317 CCM index patients we found germline variants in either of the three genes in 80 (25.2%) probands, for a total of 55 different variants. In available families, extended molecular analysis found segregation in 60 additional subjects, for a total of 140 mutated individuals. From the 55 variants, 39 occurred in KRIT1 (20 novel), 8 in CCM2 (4 novel) and 8 in PDCD10 (4 novel). Effects of the 3 novel KRIT1 missense variants were characterized in silico. We also investigated a novel PDCD10 deletion spanning exon 4-10, on patient's fibroblasts, which showed sign...

Research paper thumbnail of A novel mutation in CDH11, encoding cadherin-11, cause Branchioskeletogenital (Elsahy-Waters) syndrome

American journal of medical genetics. Part A, Jan 8, 2018

Cadherins are cell-adhesion molecules that control morphogenesis, cell migration, and cell shape ... more Cadherins are cell-adhesion molecules that control morphogenesis, cell migration, and cell shape changes during multiple developmental processes. Until now four distinct cadherins have been implicated in human Mendelian disorders, mainly featuring skin, retinal and hearing manifestations. Branchio-skeleto-genital (or Elsahy-Waters) syndrome (BSGS) is an ultra-rare condition featuring a characteristic face, premature loss of teeth, vertebral and genital anomalies, and intellectual disability. We have studied two sibs with BSGS originally described by Castori et al. in 2010. Exome sequencing led to the identification of a novel homozygous nonsense variant in the first exon of the cadherin-11 gene (CDH11), which results in a prematurely truncated form of the protein. Recessive variants in CDH11 have been recently demonstrated in two other sporadic patients and a pair of sisters affected by BSGS. Although the function of this cadherin (also termed Osteoblast-Cadherin) is not completely ...

Research paper thumbnail of Leber's hereditary optic neuropathy (LHON) in an Apulian cohort of subjects

Acta myologica : myopathies and cardiomyopathies : official journal of the Mediterranean Society of Myology, 2017

Leber's hereditary optic neuropathy (LHON) is a maternally inherited disorder that causes sev... more Leber's hereditary optic neuropathy (LHON) is a maternally inherited disorder that causes severe loss of sight in young adults, and is typically associated to mitochondrial DNA (mtDNA) mutations. Heteroplasmy of primary LHON mutations, presence of 'ancillary' mtDNA mutations, and mtDNA copy number are probably correlated with the penetrance and the severity of the disease. In this study, we performed a mutational screening in an Apulian cohort of LHON patients and we found that 41 out of 54 subjects harbored the m.11778G>A mutation, and 13 harbored the m.3460G>A mutation. Whole mtDNA sequencing was performed in three affected subjects belonging to three unrelated m.11778G>A pedigrees to evaluate the putative synergistic role of additional mtDNA mutations in determining the phenotype. Our study suggests to include haplogroup T as a possible genetic background influencing LHON penetrance and to consider the increase of mtDNA copy number as a protective factor from...

Research paper thumbnail of High Mitochondrial DNA Copy Number Is a Protective Factor From Vision Loss in Heteroplasmic Leber's Hereditary Optic Neuropathy (LHON)

Investigative Opthalmology & Visual Science, 2017

PURPOSE. Leber's hereditary optic neuropathy (LHON) is a mitochondrial disease that typically cau... more PURPOSE. Leber's hereditary optic neuropathy (LHON) is a mitochondrial disease that typically causes bilateral blindness in young men. It is characterized by as yet undisclosed genetic and environmental factors affecting the incomplete penetrance. METHODS. We identified 27 LHON subjects who possess heteroplasmic primary LHON mutations. Mitochondrial DNA (mtDNA) copy number was evaluated. RESULTS. The presence of centrocecal scotoma, an edematous, hyperemic optic nerve head, and vascular tortuosity, as well as telangiectasia was recognized in affected subjects. We found higher cellular mtDNA content in peripheral blood cells of unaffected heteroplasmic mutation carriers with respect to the affected. CONCLUSIONS. The increase of cellular mtDNA content prevents complete loss of vision despite the presence of a heteroplasmic state of LHON primary mutation, suggesting that it is a key factor responsible for penetrance of LHON.

Research paper thumbnail of Expanding the mutation spectrum in 130 probands with ARPKD: identification of 62 novel PKHD1 mutations by sanger sequencing and MLPA analysis

Journal of Human Genetics, 2016

Autosomal recessive polycystic kidney disease (ARPKD) is a rare severe genetic disorder arising i... more Autosomal recessive polycystic kidney disease (ARPKD) is a rare severe genetic disorder arising in the perinatal period, although a late-onset presentation of the disease has been described. Pulmonary hypoplasia is the major cause of morbidity and mortality in the newborn period. ARPKD is caused by mutations in the PKHD1 (polycystic kidney and hepatic disease 1) gene that is among the largest human genes. To achieve a molecular diagnosis of the disease, a large series of Italian affected subjects were recruited. Exhaustive mutation analysis of PKHD1 gene was carried out by Sanger sequencing and multiple ligation probe amplification (MLPA) technique in 110 individuals. A total of 173 mutations resulting in a detection rate of 78.6% were identified. Additional 20 unrelated patients, in whom it was not possible to analyze the whole coding sequence, have been included in this study. Taking into account the total number (n = 130) of this cohort of patients, 107 different types of mutations have been detected in 193 mutated alleles. Out of 107 mutations, 62 were novel: 11 nonsense, 6 frameshift, 7 splice site mutations, 2 in-frame deletions and 2 multiexon deletion detected by MLPA. Thirty-four were missense variants. In conclusion, our report expands the spectrum of PKHD1 mutations and confirms the heterogeneity of this disorder. The population under study represents the largest Italian ARPKD cohort reported to date. The estimated costs and the time invested for molecular screening of genes with large size and allelic heterogeneity such as PKHD1 demand the use of next-generation sequencing (NGS) technologies for a faster and cheaper screening of the affected subjects.