Clinical and Molecular Genetic Analysis of Cases with Ectodermal Dysplasia.

INTRODUCTION: Ectodermal dysplasias are a group of >200 clinically and congenitally heterogeneous disorders characterized by abnormal development in the ectodermal structures, such as hair, nails, teeth, and sweat glands. We report here the clinical and molecular genetic analysis of five Greek families with different types of ectodermal dysplasia (ED). SUBJECTS: The study involved 15 individuals from 5 Greek families that included 8 ED patients, 5 carriers of recessive X-linked or autosomal ED, and 2 healthy relatives. After genetic counseling, the parents signed an informed consent form before subsequent genetic testing. METHODS: Genomic DNA was isolated from white blood cells of all studied individuals. The search for mutations was realized in patients' DNA samples using next-generation sequencing (NGS) gene panel, whole exome sequencing (WES), chromosomal microarray analysis (CMA), and multiplex ligation-dependent probe amplification (MLPA) technique. RESULTS: The clinical diagnosis of common X-linked recessive hypohidrotic ectodermal dysplasia (HED) was suspected in five male patients with partial anodontia of baby and permanent teeth, hypohidrosis, and thin hair from three families. All HED patients were hemizygous for deletions in the EDA1 gene (Xq13.1): three related patients had a 20 bp deletion, one had a 19 bp deletion, and one had a 180 bp deletion. A female patient had the rare autosomal dominant syndrome of ankyloblepharon-ectodermal dysplasia-cleft lip/palate (AEC) caused by heterozygous missense mutation in the TP63 gene (3q28) that appeared de novo. Two siblings with hypotrichosis and hypodontia, a female and a male, had two pathogenic mutations in compound heterozygosity in the TSPEAR gene (21q22.3); therefore they presented with ectodermal dysplasia type 14 (ECTD14). CONCLUSION: Clinical and molecular genetic analysis may set an accurate diagnosis of different types of ED. In the reported families, genetic diagnosis and genetic counselling assisted the parents to view their children's condition realistically and to cooperate with the specialists who will contribute to the best possible treatment for their children.

Investigation of Genetic Association Between a High Activity Variant of Cathepsin G and Risk for Basal Cell Carcinoma.

BACKGROUND/AIM: Cathepsin G (CTSG) has been identified as an inhibitor of breast, bladder, and colorectal cancers. The G allele of the N125S (A/G, rs45567233) functional polymorphism of the CTSG gene confers increased serum CTSG activity and has been associated with cardiovascular and neurovascular diseases. This study examined the possible correlation between the pathogenesis of basal cell carcinoma (BCC) and the functional polymorphism CTSG N125S. PATIENTS AND METHODS: A total of 197 DNA samples were examined, comprising 98 BCC patients and 99 control samples of Greek origin. The CTSG N125S polymorphism was molecularly genotyped using PCR amplification, followed by enzyme digestion, and agarose gel electrophoresis of the amplified DNA fragments. RESULTS: There was no statistically significant difference in the genotypic and allelic frequencies between the patient and the control groups. CONCLUSION: There is no association between the CTSG N125S polymorphism and pathogenesis of BCC.

Molecular Modeling Analysis Provides Genotype-Phenotype Correlation Insights in a Patient with Ankyloblepharon-Ectodermal Dysplasia-Clefting Syndrome.

Ankyloblepharon-ectodermal defects-cleft lip/palate (AEC) syndrome is a rare autosomal dominant disorder. AEC is caused by mutations in the TP63 gene that encodes the tumor suppressor p63 protein, itself involved in the regulation of epidermal proliferation, development, and differentiation. We present here a typical AEC case of a four-year-old girl with extensive skin erosions and erythroderma of the scalp and the trunk, and to a lesser extent of the limbs, nail dystrophy on the fingers and toes, xerophthalmia, a high-arched palate, oligodontia, and hypohidrosis. Mutation analysis of the TP63 gene detected a de novo missense mutation in exon 14 (c.1799G>T; p.Gly600Val). We discuss the phenotype-genotype correlation by presenting the clinical features of AEC in the patient, and the effect of the detected mutation in p63 structure and function using protein structural modeling, in view of similar cases in the literature. We performed a molecular modeling study in order to link the effect on the protein structure level of the missense mutation G600V. We noted that the introduction of the bulkier Valine residue in place of the slim Glycine residue caused a significantly altered 3D conformational arrangement of that protein region, pushing away the adjacent antiparallel α helix. We propose that the introduced locally altered structure of the G600V mutant p63 has a significant functional effect on specific protein-protein interactions, thus affecting the clinical phenotype.

A novel deletion of exon 4 in the Ectodysplasin A gene associated with X-linked hypohidrotic ectodermal dysplasia.

OBJECTIVE: Identify the disease-causing mutation in a patient with features of X-linked hypohidrotic ectodermal dysplasia, which is a genetic disorder characterized by hypodontia, hypohidrosis and hypotrichosis. It is caused by mutations in Ectodysplasin A gene, which encodes ectodysplasin A, a member of the tumor necrosis factor superfamily. DESIGN: Genetic analysis, was performed using chromosomal microarray analysis, whole exome sequencing and multiplex ligation-dependent probe amplification analysis in a 4-year-old boy with hypohidrotic ectodermal dysplasia features. Moreover, the boy's parents were tested for clinically significant findings identified in order to elucidate the pattern of inheritance of the finding detected in the proband. RESULTS: A novel deletion of entire exon 4 in Ectodysplasin A gene identified in the 4-year-old patient. This deletion was found in heterozygous state in the mother of the proband and was not detected in his father. RNA analysis revealed an in-frame deletion r.527_706del, p.(176_236del) in exon 4 of the Ectodysplasin A gene. CONCLUSION: We identified a novel gross deletion in the Ectodysplasin A gene in a male patient with X-linked hypohidrotic ectodermal dysplasia. Clinical and molecular genetic analysis are crucial to set an accurate diagnosis in patients with hypohidrotic ectodermal dysplasia. These results highlight the importance of the collagen domain of Ectodysplasin A, encoded by exon 4, for its function in vivo.