Hereditary hypotrichosis simplex (HHS) is a rare form of nonsyndromic hereditary hypotrichosis without characteristic hair shaft anomalies. Affected individuals typically show normal hair at birth, but hair loss and thinning of the hair shaft start during early childhood and progress with age. HHS can be largely divided into 2 forms: the scalp-limited form (e.g., 146520) and the generalized form, such as HYPT1, in which all body hair is affected. HHS is characterized by progressive hair follicle miniaturization, which is a typical feature of androgenetic alopecia (see 109200). HHS can be inherited either as an autosomal dominant or autosomal recessive trait (e.g., HYPT8, 278150) (summary by Shimomura et al., 2010).
Genetic Heterogeneity of Nonsyndromic Hypotrichosis
See also HYPT2 (146520), caused by mutation in the CDSN gene (602593) on chromosome 6p21; HYPT3 (613981), caused by mutation in the KRT74 gene (608248) on chromosome 12q13; HYPT4 (146550), caused by mutation in the HRURF gene (619257) on chromosome 8p21; HYPT5 (612841), caused by mutation in the EPS8L3 gene (614989) on chromosome 1p13; HYPT6 (607903), caused by mutation in the DSG4 gene (607892) on chromosome 18q12; HYPT7 (604379), caused by mutation in the LIPH gene (607365) on chromosome 3q27; HYPT8 (278150), caused by mutation in the LPAR6 gene (609239) on chromosome 13q14; HYPT9 (614237), mapped to chromosome 10q11.23-q22.3; HYPT10 (614238), mapped to chromosome 7p22.3-p21.3; HYPT11 (615059), caused by mutation in the SNRPE gene (128260) on chromosome 1q32; HYPT12 (615885), caused by mutation in the RPL21 gene (603636) on chromosome 13q12; HYPT13 (615896), caused by mutation in the KRT71 gene (608245) on chromosome 12q13; HYPT14 (618275), caused by mutation in the LSS gene (600909) on chromosome 21q22; and HYPT15 (620177), caused by mutation in the C3ORF52 gene (611956) on chromosome 3q13. [from
OMIM]