Genetics
Main article: Androgenic alopecia
Much research went into the genetic component of male pattern baldness, or androgenetic alopecia (Androgenetic Alopecia). Research indicates that susceptibility to premature male pattern baldness is largely X-linked. Other genes that are not sex linked are also involved.
German researchers name the androgen receptor gene as the cardinal prerequisite for balding.[7] They conclude that a certain variant of the androgen receptor is needed for Androgenetic Alopecia to develop. In the same year the results of this study were confirmed by other researchers.[8] This gene is recessive and a female would need two X chromosomes with the defect to show typical male pattern alopecia. Seeing that androgens and their interaction with the androgen receptor are the cause of Androgenetic Alopecia it seems logical that the androgen receptor gene plays an important part in its development.
Other research in 2007 suggests another gene on the X chromosome, that lies close to the androgen receptor gene, is an important gene in male pattern baldness. They found the region Xq11-q12 on the X-chromosome to be strongly associated with Androgenetic Alopecia in males. They point at the EDA2R gene as the gene that is mostly associated with Androgenetic Alopecia. This finding has been replicated in at least three following independent studies.
Other genes involved with hair loss have been found. One of them being a gene on chromosome 3. The gene is located at 3q26.[9] This gene is also involved in a type of baldness associated with mental retardation. This gene is recessive .
Another gene that might be involved in hair loss is the P2RY5. This gene is linked to hair structure. Certain variants can lead to baldness at birth while another variant causes "wooly hair".[10]
Recent research confirmed the X linked androgen receptor as the most important gene. With a gene on chromosome 20 being the second most important determinant gene (snpedia)
