Background: Hypotrichosis of the Marie Unna type (HMU) is a rare autosomal dominant disorder characterized by male-pattern hair loss with childhood onset and anomalies of the hair shaft.
Objectives: We aimed to evaluate a number of chromosomal loci as possible candidate regions for HMU.
Methods: A linkage analysis was performed in a large German family using microsatellite markers spanning candidate regions on chromosomes 8, 12 and 17.
Results: We found that the HMU locus maps to chromosomal region 8p21 in a 13.01-cM interval between markers D8S1145 and D8S1771. This interval harbours the hairless gene (HR). Mutational analysis of HR on the genomic and transcript levels revealed no pathogenic mutation.
Conclusions: Our findings, together with a recent report of two unrelated families of Dutch and British origin, provide evidence for a hair growth regulatory gene distinct from HR in chromosomal region 8p21.