Hypotrichosis 9

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

Clinical Features

Naz et al. (2010) reported a 4-generation Pakistani family in which 4 individuals, 2 males and 2 females, had hypotrichosis. All 4 individuals had brown, thin, sparse hair on scalp, arms, and legs. Eyebrows and eyelashes were black and unaffected. At birth, hair on the scalp was sparse and thin. Following ritual shaving, the hair regrew sparsely in a few months. Teeth, nails, sweating, and hearing were normal, and there were no neurologic abnormalities or facial dysmorphisms. Heterozygous carrier individuals were indistinguishable from genotypically normal individuals.

Inheritance

The pedigree pattern in the family with hypotrichosis reported by Naz et al. (2010) was consistent with autosomal recessive inheritance.

Mapping

Using linkage analysis, Naz et al. (2010) mapped hereditary hypotrichosis in a 4-generation consanguineous Pakistani family to chromosome 10q11.23-q22.3, in a 28.5-Mb region between markers D10S538 (51.9 Mb) and D10S2327 (80.4 Mb) (build 36.2). A maximum multipoint lod score of 3.26 was obtained for several markers within the region.

Molecular Genetics

Naz et al. (2010) sequenced coding exons and splice junction sites of 4 genes in the critical region and failed to find any functional sequence variants. Linkage to genes known to be involved in hypotrichosis had been excluded.