Evidence of increased DNA methylation of the androgen receptor gene in occipital hair follicles from men with androgenetic alopecia

Funding sources: this work was supported by a Fred Bauer Research Grant from the Australasian College of Dermatologists, and the St Vincent’s Research Endowment Fund. J.A.E. is supported by a National Health and Medical Research Council (Australia) Capacity Building Grant in Population Health. Conflicts of interest: none declared. Madam, Androgenetic alopecia (AGA), the patterned baldness commonly seen in Caucasian men, is associated with the androgen receptor (AR) gene.1 Concurrently, AR protein expression appears markedly increased within balding vertex compared with occipital hair follicles.2, 3 This is thought to be a major contributing factor to the site‐specific follicle miniaturization and resultant hair loss in AGA. DNA methylation involves the covalent addition of a methyl group to the cytosine base within CpG dinucleotides.4 Enriched regions of CpG, known as CpG islands, are often associated with the 5′ promoter regions of genes, and methylation of such regions is associated with reduced gene expression.4 Although the exact mechanism responsible for establishing or modifying methylation at specific genes is largely unknown, it is possible that DNA sequence variants in the vicinity of a gene may be relevant, modulating risk for heritable diseases such as AGA that depend on developmental stage‐ and tissue‐specific gene expression.