Unexpectedly High Carrier Rates and Genotype/Phenotype Correlation: LIPH Mutations in Japanese Autosomal Recessive Woolly Hair/Hypotrichosis

In a study conducted 6 years ago, researchers investigated the LIPH gene mutations in 14 Japanese patients with autosomal recessive woolly hair/hypotrichosis (ARWH). They found that 10 patients had homozygous c.736T > A mutations, 3 had compound heterozygous c.736T > A and c.742C > A mutations, and 1 had a homozygous c.742C > A mutation. The mild phenotype of hypotrichosis with woolly hair was associated with the homozygous c.736T > A mutation, while the severe phenotype of complete baldness was seen in the patient with the homozygous c.742C > A mutation. The researchers also found that the allele frequencies of c.736T > A and c.742C > A were 0.87% (16/1838) and 0.16% (3/1838), respectively, and the carrier rates were 1.7% (16/919) and 0.32% (3/919), respectively. The combined carrier rate of the founder LIPH mutations was about 2.1% in the Japanese population.