Hypotrichosis simplex can affect all body hair (generalized; see 605389) or be limited to the scalp. Usually patients with the scalp-limited form of hypotrichosis present with normal hair at birth; they experience a progressive, gradual loss of scalp ... Hypotrichosis simplex can affect all body hair (generalized; see 605389) or be limited to the scalp. Usually patients with the scalp-limited form of hypotrichosis present with normal hair at birth; they experience a progressive, gradual loss of scalp hair beginning at the middle of the first decade and leading to almost complete loss of scalp hair by the third decade. A few sparse, fine, short hairs remain in some individuals. Body hair, beard, eyebrows, axillary hair, teeth, and nails develop normally. Light and electron microscopy of hairs from patients with early hypotrichosis simplex revealed no structural changes, whereas hairs from patients with advanced hypotrichosis showed focal areas of defective cuticular structure. Men and women are equally affected (summary by Betz et al., 2000). For a discussion of genetic heterogeneity of hypotrichosis simplex of the scalp, see 146520.
Wasif et al. (2011) described a 4-generation consanguineous Pakistani family with hypotrichosis limited to the scalp. The 14 affected individuals were described as having been born with sparse hair on the scalp. After ritual shaving, which is usually ... Wasif et al. (2011) described a 4-generation consanguineous Pakistani family with hypotrichosis limited to the scalp. The 14 affected individuals were described as having been born with sparse hair on the scalp. After ritual shaving, which is usually performed a week after birth, hair regrew but began thinning between ages 3 and 5. Eyebrows, eyelashes, skin, sweating, teeth, and nails were normal, and affected males showed normal mustache and beard hair.
In a 4-generation consanguineous Pakistani family with autosomal dominant hypotrichosis of the scalp, Wasif et al. (2011) identified a heterozygous missense mutation in the KRT74 gene (D482N; 608248.0003). The mutation was not detected in 300 unrelated control individuals. ... In a 4-generation consanguineous Pakistani family with autosomal dominant hypotrichosis of the scalp, Wasif et al. (2011) identified a heterozygous missense mutation in the KRT74 gene (D482N; 608248.0003). The mutation was not detected in 300 unrelated control individuals.