The gene for male-pattern baldness (androgen receptor) has traditionally been linked to the X chromosome which means mom passes it on to her sons. Now, two new independent studies published yesterday at the Nature Genetics identified association between hair loss and chromosome 20.
A genome-wide association study (GWAS) for male-pattern baldness, or androgenetic alopecia, identified a new association at chromosome 20p11.22, between the PAX1 and FOXA2 genes, and confirmed a previous association with the gene encoding the androgen receptor in the X. Tim Spector and colleagues found that 1 in 7 men carry both the chromosome X and chromosome 20 variants, and that these men have a 7-fold risk of having pattern baldness.
Another independent GWAS found overwhelming evidence for five SNPs on chromosome 20p11 and confirmed the results on X, but did not find any gene-gene interaction between the two regions, suggesting that the locus on chromosome 20 may play an as-yet unidentified role in hair loss. These new results now show that more than one gene is responsible for hair loss and explains why there are similarities between a balding father and his son.
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