Cristina Has - Academia.edu (original) (raw)

Papers by Cristina Has

American Journal of Medical Genetics Part A, 2021

Institute of Human Genetics, University of Bonn, School of Medicine & University Hospital Bon... more Institute of Human Genetics, University of Bonn, School of Medicine & University Hospital Bonn, Bonn, Germany Givi Zhvania Academic Clinic of Pediatrics, Tbilisi State Medical University, Tbilisi, Georgia Cologne Center for Genomics, University of Cologne, Cologne, Germany Department of Pediatrics, University of Bonn, School of Medicine & University Hospital Bonn, Bonn, Germany Department of Dermatology, Medical Center University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany Institute of Structural Biology, University of Bonn, School of Medicine, Bonn, Germany

Deutsches Aerzteblatt Online, 2020

Journal of Investigative Dermatology, 2016

Kindler syndrome, a distinct type of epidermolysis bullosa, is a rare disorder caused by mutation... more Kindler syndrome, a distinct type of epidermolysis bullosa, is a rare disorder caused by mutations in FERMT1, encoding kindlin-1. Most FERMT1 mutations lead to premature termination codons and absence of kindlin-1. Here we investigated the molecular and cellular consequences of a naturally occurring FERMT1 mutation, c.299_301del resulting in a single amino acid deletion, p.R100del. The mutation led to a 50% reduction of FERMT1 mRNA and 90% reduction of kindlin-1 protein in keratinocytes derived from the patient, as compared with control cells. The misfolded p.R100del kindlin-1 mutant was lysosomally degraded and launched a homeostatic unfolded protein response. Sodium-phenylbutyrate significantly increased kindlin-1 mRNA and protein levels and the area of mutant cells, acting as a chemical chaperone and probably also as a histone deacetylase inhibitor. In a recombinant system, low levels of wild-type or p.R100del mutant kindlin-1 were sufficient to improve the cellular phenotype in respect of spreading and proliferation as compared with kindlin-1 negative keratinocytes. The study of this hypomorphic mutation provides evidence that low amounts of kindlin-1 are sufficient to improve the epidermal architecture and Kindler syndrome cellular phenotype and proposes a personalized chaperone therapy for the patient.

Journal of Investigative Dermatology, 2015

Immunohistologic demonstration of plateletderived growth factor (PDGF) and sisoncogene expression... more Immunohistologic demonstration of plateletderived growth factor (PDGF) and sisoncogene expression in scleroderma. J Investig Dermatol Symp Proc 92:301-3 Lang WH, Sandoval JA (2014) Detection of PI3K inhibition in human neuroblastoma using multiplex luminex bead immunoassay: a targeted approach for pathway analysis.

The Journal of investigative dermatology, 2014

comprehensive cancer registries, did not increase (Holterhues et al., 2010). The strength of our ... more comprehensive cancer registries, did not increase (Holterhues et al., 2010). The strength of our study lies in the use of population-based data, which provide a large sample size with enough statistical power to conduct incidence analyses. In addition to the aforementioned registration issues, another limitation is underreporting. Four to six percent of CLs categorized as CTCL in the SEER database were found to have B-cell lineage under the SEER variable ''grade'' (Criscione and Weinstock, 2007; Imam et al., 2013). In addition, the rarity of CBCL makes trend evaluation over time difficult. A third significant limitation is that CBCL can represent primary versus secondary skin involvement. Although cases were counted using anatomic sites coded for skin, it was difficult to distinguish whether these patients had codes of skin only (primary skin involvement) or had non-skin sites in addition (secondary skin involvement). Thus, there is likely a mix of patients with primary versus secondary skin involvement. In conclusion, we report a stabilization of overall CBCL incidence. The causes for this trend change are unknown but may include issues with registration in the early years of SEER. Further investigation is warranted to determine the true etiologies of this finding.

British Journal of Dermatology, 2014

ABSTRACT TP63 mutations result in a variety of rare dominantly inherited syndromes, which represe... more ABSTRACT TP63 mutations result in a variety of rare dominantly inherited syndromes, which represent a spectrum of isolated malformations or overlapping combinations of epidermal appendages anomalies, malformations of the limbs and face, with other features involving organs such as mammary glands, ears and kidney(1) . Genotype-phenotype correlations are based on the location and functional effects of the TP63 mutations(1) , but phenotypic variability between the affected members of the same family has been reported(2) . Moreover, some mutations have been associated with more than one syndrome(3) . This article is protected by copyright. All rights reserved.

Acta Dermato Venereologica, 2014

Der Hautarzt, 2014

der genetisch bedingten Hautfragilität wurde erstmals für die Bindegewebsfragilität bei Ehlers-Da... more der genetisch bedingten Hautfragilität wurde erstmals für die Bindegewebsfragilität bei Ehlers-Danlos-Syndromen angewendet. Heutzutage sind aber genetische Defekte der epidermalen und dermoepidermalen Adhäsion, die zu Epidermolysis bullosa hereditaria (EB) führen, als prototypisch zu betrachten. EB umfasst eine heterogene Gruppe von genetischen Erkrankungen, die mit Bildung von Blasen oder Erosionen nach mechanischer Belastung der Haut einhergehen. Das klinische Spektrum ist breit, mit milden, bis zu schweren, früh-letalen Krankheitsbildern. Meistens ist nur die Haut betroffen, aber in manchen EB-Subtypen kommt es zu extrakutanen Manifestationen. Die Ära der Mutationsanalysen und der Next-Generation-Sequenzierung resultiert in die Diagnose neuer, seltener EB-Subtypen, aber auch in die Identifizierung milder Formen der Hautfragilität, die in der Regel spät diagnostiziert werden. Auf diese wird in diesem Beitrag näher eingegangen.

Journal of Allergy and Clinical Immunology, 2015

's Methods section in the Online Repository). These showed an irregular distribution of LEKTI and... more 's Methods section in the Online Repository). These showed an irregular distribution of LEKTI and filaggrin within the granular and upper spinous layers of the patient's skin, which contrasted with the well-demarcated localization seen in control skin (Fig 2, C and D). In situ zymographies demonstrated a moderate increase in protease activity in the patient's epidermis compared with the LEKTI 420K/420K healthy control skin but less than in the LEKTI-negative skin of a patient with NS (Fig 2, E). In line with these results, immunoblotting and quantitative real-time PCR demonstrated a strong reduction of LEKTI protein and mRNA and FLG mRNA in the patient's keratinocytes compared with that seen in control cells (Fig 2, F and G). The decrease in LEKTI expression combined with the heterozygous variant p.E420K results in a strong reduction in the LEKTI proteolytic fragment (D6D9), which was associated with susceptibility to atopic dermatitis. 8 The interpretation of these observations is challenging, but they suggest that interactions between mutant ichthyin, LEKTI, and filaggrin exist. The atypical ultrastructure of the patient's skin, lacking the characteristic features confined by ichthyin mutations, strongly supports the modifying influence of the additional LEKTI and filaggrin variants (see Fig E1). The complexity of this molecular interplay cannot be fully addressed here. However, our global genetic analysis points to this ''personalized'' genetic constellation as the cause for high IgE levels and allergic sensitizations and suggests that SPINK5 and FLG functional variants become relevant in the presence of additional mutations, leading to clear keratinization defects, as seen with NIPAL4 in our patient. We thank Ioannis Athanasiou, Juna Leppert, and Kaethe Thoma for expert technical assistance. In particular, we thank the patient and his family. The contribution of the Center for Human Genetics Freiburg, led by Dr J€ urgen Kohlhase as a sequencing facility, is acknowledged.

The British journal of dermatology, 2015

Monoallelic desmoglein 1 mutations have been known for many years to cause striate palmoplantar k... more Monoallelic desmoglein 1 mutations have been known for many years to cause striate palmoplantar keratoderma, but only recently, biallelic loss-of-function mutations were associated with a new disorder, designated as SAM syndrome (comprising severe dermatitis, multiple allergies and metabolic wasting) in two consanguineous families. We report on a new case from a third independent family with the homozygous nonsense mutation, c.2659C>T, p.R887* in exon 15 of DSG1 (desmoglein 1 gene). This mutation led to mRNA decay and loss of expression of desmoglein 1. The clinical phenotype consisted of severe palmoplantar keratoderma, dermatitis and multiple allergies. In contrast to the previous cases, malabsorption, hypoalbuminaemia, developmental delay, hypotrichosis or severe recurrent infections were not observed.

Orphanet Journal of Rare Diseases, 2014

Background: Inherited ichthyoses or Mendelian disorders of cornification (MeDOC) are clinically h... more Background: Inherited ichthyoses or Mendelian disorders of cornification (MeDOC) are clinically heterogeneous disorders with high unmet therapeutic needs, which are characterized by skin hyperkeratosis and scaling. Some MeDOC types are associated with defects of the epidermal lipid metabolism, resulting in perturbed barrier permeability and subsequent epidermal hyperplasia, hyperkeratosis and inflammation. An example is the CHILD (congenital hemidysplasia with ichthyosiform nevus and limb defects) syndrome, an X-linked dominant multisystem MeDOC caused by mutations in the NSDHL (NAD(P)H steroid dehydrogenase-like protein) gene, which is involved in the distal cholesterol biosynthetic pathway. The skin manifestations of the CHILD syndrome have been attributed to two major mechanisms: deficiency of cholesterol, probably influencing the proper corneocyte membrane formation, and toxic accumulation of aberrant steroid precursors. Methods: Here we addressed the efficacy of an ointment containing cholesterol and simvastatin, an agent inhibiting endogenous cholesterol synthesis in a compassionate-use treatment of three patients with CHILD syndrome. To test the specificity of this therapeutic approach, we applied the same topical treatment to two patients with other types of MeDOC with disturbed skin lipid metabolism. Results: The therapy with simvastatin and cholesterol was highly effective and well-tolerated by the CHILD syndrome patients; only lesions in the body folds represented a therapeutic challenge. No improvement was noted in the patients with other types of MeDOC. Conclusions: This therapy is inexpensive and accessible to every patient with CHILD syndrome, because both simvastatin and cholesterol are available worldwide. Our data provide initial evidence of the specificity of the therapeutic effect of the simvastatin-cholesterol ointment in CHILD syndrome in comparison to other types of MeDOC.

Journal of Medical Genetics, 2011

Background Junctional epidermolysis bullosa (JEB), a group of hereditary skin fragility disorders... more Background Junctional epidermolysis bullosa (JEB), a group of hereditary skin fragility disorders, is associated with a wide variety of phenotypes, although all forms are characterized by trauma-induced skin blistering and tissue separation at the dermalepidermal junction zone. A subgroup, coined JEB-other, is associated with mutations in the COL17A1 gene encoding collagen XVII or, more rarely, with mutations in the laminin 332 genes LAMA3, LAMB3, or LAMC2. The objective of this study is comprehensive genotypephenotype analysis in JEB-other patients with COL17A1 mutations and elucidation of disease mechanisms underlying different skin phenotypes. Methods and results COL17A1 mutations and their clinical and cellular consequences were systematically analyzed in 43 patients with JEB-other. Cell culture, RT-PCR and protein biochemistry were applied to assess the effects of splice-site mutations, i.e. the nature and amounts of transcripts and polypeptides synthesized and their association with the phenotypic outcome. Thirty-four distinct COL17A1 mutations were disclosed, 12 of them novel. mRNA and protein analyses demonstrated that patients with only about 12-14% of the physiological collagen XVII levels had mild cutaneous involvement and a long life span. Conclusions In contrast to complete null phenotypes, presence of minor amounts of collagen XVII protein in JEB skin is associated with mild phenotypic manifestations. The data have significant implications for design of molecular therapies for JEB, since they suggest that already a low extent of collagen XVII restoration will improve skin stability and alleviate symptoms.

Journal of Investigative Dermatology, 2005

Mutations in the collagen XVII gene, COL17A1, are associated with junctional epidermolysis bullos... more Mutations in the collagen XVII gene, COL17A1, are associated with junctional epidermolysis bullosa. Most COL17A1 mutations lead to a premature termination codon (PTC), whereas only a few mutations result in amino acid substitutions or deletions. We describe here two novel glycine substitutions, G609D and G612R, and a splice site mutation resulting in a deletion of three Gly-X-Y amino acid triplets. In order to investigate the molecular pathomechanisms of non-PTC mutations, G609D and G612R and two previously known substitutions, G627V and G633, and deletion of the amino acids 779-787 were introduced into recombinant collagen XVII. The thermal stability of the mutated collagens was assessed using trypsin digestions at incremental temperatures. All the four glycine substitutions significantly destabilized the ectodomain of collagen XVII, which manifested as 161C-201C lower T m (midpoint of the helix-to-coil transition). These results were supported by secondary structure predictions, which suggested interruptions of the collagenous triple helix within the largest collagenous domain, Col15. In contrast, deletion of the three full Gly-X-Y triplets, amino acids 779-787, had no overall effect on the stability of the ectodomain, as the deletion was in register with the triplet structure and also generated compensatory changes in the NC15 domain.

Journal of Investigative Dermatology, 2012

Tan T, Chu G (2002) p53 binds and activates the xeroderma pigmentosum DDB2 gene in humans but not... more Tan T, Chu G (2002) p53 binds and activates the xeroderma pigmentosum DDB2 gene in humans but not mice. Mol Cell Biol 22: 3247-54 Tang JY, Hwang BJ, Ford JM et al. (2000) Xeroderma pigmentosum p48 gene enhances global genomic repair and suppresses UV-induced mutagenesis. Mol Cell 5:737-44 Teichert A, Elalieh H, Elias PM et al. (2011) Overexpression of hedgehog signaling is associated with epidermal tumor formation in vitamin D receptor-null mice. J Invest Dermatol 131:2289-97 Yeh K, Oh D (2002) Efficient repair of UVinduced DNA damage in terminally differentiated keratinocytes.

Journal of Investigative Dermatology, 2014

Revertant mosaicism has been reported in several inherited diseases, including the genetic skin f... more Revertant mosaicism has been reported in several inherited diseases, including the genetic skin fragility disorder epidermolysis bullosa (EB). Here, we describe the largest cohort of seven patients with revertant mosaicism and dystrophic EB (DEB), associated with mutations in the COL7A1 gene, and determine the underlying molecular mechanisms. We show that revertant mosaicism occurs both in autosomal dominantly and recessively inherited DEB. We found that null mutations resulting in complete loss of collagen VII and severe disease, as well as missense or splice-site mutations associated with some preserved collagen VII function and a milder phenotype, were corrected by revertant mosaicism. The mutation, subtype, and severity of the disease are thus not decisive for the presence of revertant mosaicism. Although collagen VII is synthesized and secreted by both keratinocytes and fibroblasts, evidence for reversion was only found in keratinocytes. The reversion mechanisms included back mutations/mitotic recombinations in 70% of the cases and second-site mutations affecting splicing in 30%. We conclude that revertant mosaicism is more common than previously assumed in patients with DEB, and our findings will have implications for future therapeutic strategies using the patient's naturally corrected cells as a source for cell-based therapies.

Journal of Investigative Dermatology, 2013

Painful stimuli evoke itch in patients with chronic pruritus: Central sensitization for itch. Neu... more Painful stimuli evoke itch in patients with chronic pruritus: Central sensitization for itch. Neurology 62:212-7 Imamachi N, Park GH, Lee H et al. (2009) TRPV1expressing primary afferents generate behavioral responses to pruritogens via multiple mechanisms.

Journal of Clinical Investigation, 2012

Spontaneous gene repair, also called revertant mosaicism, has been documented in several genetic ... more Spontaneous gene repair, also called revertant mosaicism, has been documented in several genetic disorders involving organs that undergo self-regeneration, including the skin. Genetic reversion may occur through different mechanisms, and in a single individual, the mutation can be repaired in various ways. Here we describe a disseminated pattern of revertant mosaicism observed in 6 patients with Kindler syndrome (KS), a genodermatosis caused by loss of kindlin-1 (encoded by FERMT1) and clinically characterized by patchy skin pigmentation and atrophy. All patients presented duplication mutations (c.456dupA and c.676dupC) in FERMT1, and slipped mispairing in direct nucleotide repeats was identified as the reversion mechanism in all investigated revertant skin spots. The sequence around the mutations demonstrated high propensity to mutations, favoring both microinsertions and microdeletions. Additionally, in some revertant patches, mitotic recombination generated areas with homozygous normal keratinocytes. Restoration of kindlin-1 expression led to clinically and structurally normal skin. Since loss of kindlin-1 severely impairs keratinocyte proliferation, we predict that revertant cells have a selective advantage that allows their clonal expansion and, consequently, the improvement of the skin condition. Conflict of interest: The authors have declared that no conflict of interest exists.

Journal of Biological Chemistry, 2006

Int. Journal of Clinical Pharmacology and Therapeutics, 2009