Anogenital distance or digit length ratio as measures of fetal androgen exposure: relationship to male reproductive development and its disorders

Dean, A. and Sharpe, R. M. (2013) Anogenital distance or digit length ratio as measures of fetal androgen exposure: relationship to male reproductive development and its disorders. Journal of Clinical Endocrinology and Metabolism, 98(6), pp. 2230-2238. (doi: 10.1210/jc.2012-4057) (PMID:23569219)

Abstract

Context: Male reproductive disorders evident at birth or in young adulthood are remarkably common. They are hypothesized to comprise a testicular dysgenesis syndrome (TDS), with a fetal origin involving mild androgen deficiency. Evidence Acquisition: Testing this hypothesis requires “seeing back in time.” Two ways have been proposed: measurement of anogenital distance (AGD), or measurement of the 2:4 digit length ratio. This review assesses the evidence that they reflect fetal androgen exposure and might be used to provide insight into the origin of TDS disorders. Evidence Synthesis: Supporting evidence for AGD derives from rat experimental studies that identified a fetal masculinization programming window, within which androgen action determines adult reproductive organ size, TDS disorders, and AGD. In humans, AGD is positively correlated to testis size, sperm count/fertility, penis length, and T levels, consistent with rat experimental data. The 2:4 digit ratio also shows associations with these parameters, but inconsistently between studies; evidence that the 2:4 digit ratio accurately reflects fetal androgen exposure is also equivocal. Conclusions: AGD appears to provide a reliable guide to fetal androgen exposure, although available data are limited. The next steps are to: standardize AGD measurement; obtain age-specific population data; and use AGD to evaluate the importance of fetal androgens in determining reproductive disorders and variation in testis/penis size and sperm count in the normal population. These studies should identify what, if any, clinical applications of AGD measurement are feasible—for example, its ability to predict adult-onset reproductive function and disorders.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Dean, Dr Afshan
• Authors: Dean, A., and Sharpe, R. M.
• College/School: College of Medical Veterinary and Life Sciences > School of Cardiovascular & Metabolic Health
• Journal Name: Journal of Clinical Endocrinology and Metabolism
• Publisher: Endocrine Society
• ISSN: 0021-972X
• ISSN (Online): 1945-719