Intragenic Deletion in the Desmoglein 4 Gene Underlies the Skin Phenotype in the Iffa Credo Hairless Rat

The study identified that the "hairless" phenotype in the Iffa Credo (IC) rat, an autosomal recessive hypotrichotic model, was due to a large intragenic deletion in the desmoglein 4 gene, encompassing nine exons. This genetic mutation led to impaired proliferation in the hair matrix and abnormal differentiation in the precortex zone, resulting in dysmorphic hair shafts and reduced hair bulb volume. The findings confirmed that the IC rat mutation is allelic with the lanceolate hair (lah) mutations in mice and rats, providing a new model for studying hair growth control mechanisms.