title: Ethnic variation in allele distribution of the androgen receptor (AR) (CAG)n repeat.
abstract: The androgen receptor (AR) is important in reproductive organ development,  as well as tissue homeostasis of the pancreas, liver, and skeletal muscle in  adulthood. The trinucleotide (CAG)(n) repeat polymorphism in exon 1  of the AR gene is thought to regulate AR activity, with longer alleles  conferring reduced receptor activity. Therefore, the evaluation of the allelic  distribution of the AR (CAG)(n) repeat in various ethnic  groups is crucial in understanding the interindividual variability in AR  activity. We evaluated ethnic variation of this AR polymorphism by  genotyping individuals from the multiethnic Hyperglycemia and Adverse  Pregnancy Outcome study cohort. We genotyped 4421 Caucasian mothers and 3365  offspring of European ancestry; 1494 Thai mothers and 1742 offspring; 1119  Afro-Caribbean mothers and 1142 offspring; and 780 Hispanic mothers and 770  offspring of Mexican ancestry from Bellflower, California. The distributions  of (CAG)(n) alleles among all 4 ethnic groups are significantly  different (P < .0001). Pairwise tests confirmed significant  differences between each pair of ethnicities tested (P <  10(-28)). The relative AR (CAG)(n) repeat  length in the different groups was as follows: Afro-Caribbean (shortest repeat  lengths and greatest predicted AR activity) < Caucasian < Hispanic <  Thai (longest repeat length and lowest predicted AR activity). Significant  interethnic differences in the allele frequencies of the AR exon 1  (CAG)(n) polymorphism exist. Our results suggest that there may be  potential ethnic differences in androgenic pathway activity and androgen  sensitivity.
authors: Division of Endocrinology, Metabolism, and Molecular Medicine, Northwestern University, Feinberg School of Medicine, 303 E Chicago Ave, Chicago, IL 60611, USA.
authors: Christine M
authors: CM
authors: Ackerman
authors: Lynn P
authors: LP
authors: Lowe
authors: Hoon
authors: H
authors: Lee
authors: M Geoffrey
authors: MG
authors: Hayes
authors: Alan R
authors: AR
authors: Dyer
authors: Boyd E
authors: BE
authors: Metzger
authors: William L
authors: WL
authors: Lowe
authors: Margrit
authors: M
authors: Urbanek
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