Monilethrix: A Keratin HHb6 Mutation Is Co-Dominant With Variable Expression

The study focused on a large family affected by monilethrix, a rare autosomal dominant hair disorder, linked to an E410D mutation in the keratin hHb6 gene. Among 12 heterozygous family members, the mutation showed variable expression, while 3 homozygous members experienced severe symptoms, including almost complete scalp hair loss from 2 months of age and extensive follicular keratotic involvement. The variability in expression among heterozygous individuals, along with observed improvements during certain seasons and pregnancy, suggested that additional genetic or environmental factors might influence the expression of the keratin gene. This study was the first to report a co-dominant keratin hHb6 mutation leading to severe disease.