LPAR6

More than 30 LPAR6 gene mutations have been found to cause autosomal recessive hypotrichosis, a condition that results in sparse hair growth (hypotrichosis) on the scalp and, less frequently, other parts of the body. Some mutations are specific to populations with Pakistani ancestry. LPAR6 gene mutations lead to the production of an abnormal LPA₆ protein that cannot bind to LPA to regulate cell proliferation and differentiation within hair follicles. As a result, hair follicles are structurally abnormal and often underdeveloped. Irregular hair follicles alter the structure and growth of hair shafts, leading to fragile hair that breaks easily. A lack of LPA₆ protein function in the epidermis likely contributes to the skin problems sometimes seen in individuals with autosomal recessive hypotrichosis.

Mutations in the LPAR6 gene can also cause a hair condition called autosomal recessive woolly hair. People with this condition have hair that is unusually coarse, dry, fine, and tightly curled. Woolly hair typically affects only scalp hair and is present from birth. In some cases, affected individuals develop hypotrichosis as they get older. Certain LPAR6 gene mutations cause autosomal recessive woolly hair in some people and autosomal recessive hypotrichosis (described above) in others, even among members of the same family. Because of a shared genetic cause and overlapping features, it is uncertain whether these two conditions are separate disorders or part of the same disease spectrum.