Rare Diseases Symptoms Automatic Extraction

Mutations in EXPH5 result in autosomal recessive inherited skin fragility.

[epidermolysis bullosa simplex]

Several different genes have been implicated in the pathophysiology of inherited blistering skin diseases. Recently, autosomal recessive loss-of-function mutations in EXPH5 (encoding exophilin-5, also known as Slac2-b, a protein involved in intracellular vesicle transport) were identified in a new mechanobullous disease resembling a form of epidermolysis bullosa simplex (EBS). Here, we searched for mutations in EXPH5 in a 4-year-old white boy with EBS in whom initial Sanger sequencing of known genes implicated in intraepidermal skin fragility failed to identify pathogenic mutations. Transmission electron microscopy of rubbed nonlesional patient skin revealed disruption of keratinocytes in the lower epidermis with cytolysis and acantholysis, keratin filament clumping and prominent perinuclear cytoplasmic vesicles, and provided the clue to the candidate gene pathology. Sanger sequencing of genomic DNA showed compound heterozygosity for two new mutations in EXPH5, c.1947dupC (p.Pro649fsPro*11) and c.2249C>A (p.Ser750*). Immunofluorescence microscopy of patient skin showed a complete absence of exophilin-5 labelling. This case represents the third pedigree with EXPH5 mutations resulting in inherited skin fragility. The clinical and molecular data expand genotype-phenotype correlation in this new form of EBS and demonstrate the important role of exophilin-5 in keratinocyte cell biology.

Diseases presenting "loss-of-function mutations" symptom

  • achondroplasia
  • alpha-thalassemia
  • aromatase deficiency
  • child syndrome
  • cowden syndrome
  • dystrophic epidermolysis bullosa
  • epidermolysis bullosa simplex
  • erythropoietic protoporphyria
  • esophageal adenocarcinoma
  • familial hypocalciuric hypercalcemia
  • harlequin ichthyosis
  • hirschsprung disease
  • kallmann syndrome
  • kindler syndrome
  • lamellar ichthyosis
  • neonatal adrenoleukodystrophy
  • pendred syndrome
  • werner syndrome
  • x-linked adrenoleukodystrophy

This symptom has already been validated