A Missense Mutation in the Cadherin Interaction Site of the Desmoglein 4 Gene Underlies Localized Autosomal Recessive Hypotrichosis

The study identified a missense mutation in the desmoglein 4 (DSG4) gene as the cause of localized autosomal recessive hypotrichosis (LAH) in a family of Iraqi origin. The affected child exhibited sparse, brittle hair and follicular hyperkeratosis. A homozygous tandem dinucleotide transversion mutation was found, changing alanine to serine at a critical site for cadherin-cadherin dimerization, essential for cell adhesion. This mutation was distinct from previously identified deletions in Pakistani families, suggesting a broader allelic series of DSG4 mutations. The findings highlighted the importance of considering LAH in differential diagnoses of hypotrichosis.