Finding Bald Spots on Chromosome 20p11

Two independent genome-wide association studies identified new genetic susceptibility loci for androgenic alopecia (AGA), or male pattern baldness, on chromosome 20p11. The first study by Richards et al. included an initial cohort of 1,125 individuals and was followed by replication in three new cohorts totaling 4,961 individuals. They found a new locus at 20p11.22 with a combined odds ratio of 1.60 for hair loss. Additionally, 14% of men with at least one risk allele at both 20p11.22 and the AR gene had an increased odds ratio of 7.12 for AGA. The second study by Hillmer et al. involved an initial cohort of 643 individuals and a replication study with 553 individuals, all of German descent. They identified five SNPs with odds ratios ranging from 1.66 to 2.17, which were confirmed in an Australian cohort. Both studies found no significant statistical interaction between the AR and 20p11 loci. The 20p11 locus is in a gene-poor region, and the causative mutations are unknown, but nearby genes PAX1 and FOXA2 are speculated to influence AGA. Further research is needed to understand the genetic link between chromosome 20p11 variants and hair loss, which could lead to improved treatments for AGA, potentially including gene therapy.