Hypotrichosis congenita hereditaria marie unna Q84.2

Autosomal-dominantly inherited congenital hypotrichosis without associated symptoms with typical hair anomalies, which usually manifests itself only in preschool or early school age.

Autosomal-dominantly inherited mutations (so far > 17 mutations have been detected in different ethnic groups) of the "Marie Unna Hereditary Hypertrichosis" gene (MUHH gene, also U2HR gene - especially in Chinese populations), located in a region of the so-called hairless gene , chromosome: 8p21). It is believed that U2HR serves as a negative regulator of the HR gene and mutations cause a gain-of-function, which leads to an increased translation of the HR gene.

Hair missing from birth, short eyelashes, rarefied eyebrows; late, slow growth of bristly, dystrophic, difficult to comb hairs (wide hair spacing). Sparsely applied secondary hair. From the age of 10 to 25 years, increased effluvium of the scalp hairs, which leads to alopecia of the androgenetic type (see Alopecia androgenetica in women, Alopecia androgenetica in men) of varying severity (up to total alopecia). Sparsely developed secondary hair. This can also be completely absent. Between the ages of 10 and 25, hair loss begins again, sometimes up to total alopecia, including loss of eyelashes and eyebrows.

• Pili torti (rotation of the hair shafts by 90 or 180 ° around their longitudinal axis at intervals of 2-10 mm), flattening the hair.
• Scanning electron microscope: cuticle defects, longitudinal grooving of the hair shafts resulting in a triangular or kidney-shaped cross-section ( Pili canaliculi).

Possibly hair transplant, s.a. Pili torti. No other therapy is known.

1. Chlebarov S (1985) Hypotrichosis congenita hereditaria Marie Unna. Z Hautkr 60: 583-596
2. Cichon S et al (2000) A distinct gene close to the hairless locus on chromosome 8p underlies hereditary Marie Unna type hypotrichosis in a German family. Br J Dermatol 143: 811-814
3. Green J et al (2003) Progressive patterned scalp hypotrichosis, with wiry hair, onycholysis, and intermittently associated cleft lip and palate: clinical and genetic distinction from Marie Unna. J Investig Dermatol Symp Proc 8: 121-125
4. Unna M (1925) About hypotrichosis congenita hereditaria. Dermatol Weekly 81: 1167-1178
5. Wong SN et al (2002) Marie Unna hypotrichosis in a Chinese family. Pediatric Dermatol 19: 250-255
6. Zhong Z et al (2015) Identification of mutations in U2HR in two Chinese families with Marie Unna hereditary hypotrichosis. Clin Exp Dermatol 41:175-178