Hypotrichosis 5

For a general phenotypic description of Marie Unna hereditary hypotrichosis, see MUHH1 (146550).

For a discussion of genetic heterogeneity of nonsyndromic hypotrichosis, see 605389.

Clinical Features

Yan et al. (2004) reported a 4-generation Chinese family in which 9 individuals had hypotrichosis inherited in an autosomal dominant pattern. The 36-year-old female proband had little or no scalp hair at birth, with normal teeth, nails, sweating, and hearing. Intellectual and sexual development were also normal. In childhood, her hair became wiry, irregular, and difficult to manage. The forehead and parietal areas remained bald or sparse, and the eyebrows and eyelashes were always thin. Skin biopsy showed a marked reduction of mature hair follicles. Other affected family members had similar hair abnormalities.

Mapping

By genomewide linkage analysis in the Chinese family with Marie Unna hypotrichosis reported by Yan et al. (2004), Yang et al. (2005) obtained a maximum 2-point lod score of 3.01 for the markers D1S2746 and D1S2881; a maximum multipoint nonparametric lod score of 5.74 was obtained for marker D1S2881. Haplotype analysis positioned the locus to a 17.5-cM (42-Mb) interval on chromosome 1p21.1-q21.3 between markers D1S248 and D1S2345.