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Asian Journal of Andrology (2013) 15, 286–289; doi:10.1038/aja.2012.126; published online 21 January 2013
The relationship between anogenital distance and the androgen receptor CAG repeat length
Michael L Eisenberg1, Tung-Chin Hsieh2, Alexander W Pastuszak2, Matthew G McIntyre2, Rustin C Walters2, Dolores J Lamb2 and Larry I Lipshultz2
1 Department of Urology, Stanford University School of Medicine, Stanford, CA 94305, USA
2 Department of Urology, Baylor College of Medicine, Houston, TX 77030, USA
Correspondence: Dr ML Eisenberg, (eisenberg@stanford.edu)
Received 17 August 2012; Revised 10 September 2012; Accepted 10 October 2012
Advance online publication 21 January 2013
| Abstract |
Anogenital distance (AGD) is used to define degree of virilization of genital development, with shorter length being associated with feminization and male infertility. The first exon of the androgen receptor (AR) consists of a polymorphic sequence of cytosine–adenine–guanine (CAG) repeats, with longer CAG repeat lengths being associated with decreased receptor function. We sought to determine if there is an association between AGD and AR CAG repeat length. A cross-sectional, prospective cohort of men evaluated at a urology clinic at a single institution was recruited. AGD (the distance from the posterior scrotum to the anal verge) and penile length (PL) were measured. Sanger DNA sequence analysis was used to define CAG repeat length. AGD and CAG repeat lengths in 195 men were determined. On unadjusted analysis, there was no linear relationship between CAG repeat length and PL (P=0.17) or AGD (P=0.31). However, on sub-population analyses, those men with longer CAG repeat lengths (>26) had significantly shorter AGDs compared to men with shorter CAG repeat lengths. For example, the mean AGD was 41.9 vs. 32.4 mm with a CAG repeat length ≤26 vs. >26 (P=0.01). In addition, when stratifying the cohort based on AGD, those with AGD less than the median (i.e. 40 mm) had a longer CAG repeat length compared to men with an AGD >40 mm (P=0.02). In summary, no linear relationship was found between AGD and AR CAG repeat length overall.
Keywords: androgen receptor (AR); anogenital distance (AGD); genitalia; penile length (PL); perineum |
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