A Study of the androgen receptor gene polymorphism and the level of expression of the androgen receptor in androgenetic alopecia among Egyptians

Abstract

Background: Androgenetic alopecia (AGA) occurs in men and women. The
nature of the genetic predisposition to androgenetic alopecia is still unresolved. The aim of the work is to study the genotype of the androgen receptor gene (StuI polymorphism) and its relationship to AGA in a case control study and to determine the level of androgen receptor expression (AR) in the balding scalp relative to the non-balding scalp area.
Subjects and Methods: This study was conducted on one hundred individuals; 60 cases with AGA (36 males and 24 females) and 40 age and sex matched control patients (20 males and 20 females). StuI restriction fragment length polymorphism(RFLP) of exon 1 was detected by PCR based assay using genomic DNA of subjects with AGA and controls. Immunohistochemical detection of the androgen receptor (AR) using antihuman AR antibody was implemented to compare its level in the balding scalp and in the non-balding area in individuals having AGA.
Results: Analysis of StuI restriction fragment length polymorphism in exon 1 of the androgen receptor (AR) gene revealed a relatively commoner incidence of the cut allele in males with AGA relative to age and sex matched controls (the association was of border line signifi cance p=0.07. Interestingly, all persons who had maternal uncles suffering from AGA had the Stu1 cut variant of AR gene (p= 0.03 using Chi square test). Semiquantitative immunohistochemical analysis of AR in the bold scalp biopsies showed higher expression in the level of AR than the non bold bioposies within the same individual.
Conclusion: To the best of our knowledge this is the fi rst study of AR gene polymorphism and AR expression in AGA amongst Egyptians. This study contributes in the understanding of the molecular pathogenesis of AGA which could help in fi nding better therapeutic alternatives for such trait in the future.

Keywords: Androgenetic alopecia, androgen receptor, StuI polymorphism, immunohistochemical expression.