Novel Hairless Mutations in Two Kindreds with Autosomal Recessive Papular Atrichia

The study examined two families with autosomal recessive papular atrichia, identifying novel mutations in the hairless (HR) gene. In a Mexican family, a homozygous 4 bp deletion in exon 7 caused a premature stop codon, while in a South Tyrolian family, a homozygous A→G transition in exon 14 resulted in an Asn970Ser amino acid change. The latter mutation was absent in 616 control individuals, indicating its potential role in the disease. The study underscored the genetic heterogeneity of papular atrichia and suggested the involvement of the hairless protein in hair development and ossification, as affected individuals in the South Tyrolian family also showed delayed bone age. Further research was recommended to explore the functional domains of the hairless protein and the effects of missense mutations.