Caucasian male infants and boys with hypospadias exhibit reduced anogenital distance.

BACKGROUND: Animal models of endocrine dysfunction have associated male genital defects with reduced anogenital distance (AGD). Human studies have correlated shorter AGD with exposure to putative endocrine disruptors in the environment but have not examined AGD in hypospadiac boys. We measured AGD in boys with hypospadias and those with normal genitals.
METHODS: Data were collected prospectively on boys undergoing urologic procedures at the University of California San Francisco and the Children's Hospital of Oakland, CA, USA. Data included age, race, height, weight, BMI, urologic diagnoses and AGD. To minimize any potential effects of race on observed AGD, we examined only Caucasian boys. Differences between boys with hypospadias and those with normal genitals were examined through two-tailed Student's t-tests.
RESULTS: One hundred and nineteen Caucasian boys ranging in age from 4 to 86 months underwent AGD measurement, of which 42 and 77 were boys with normal genitals and hypospadias, respectively. The mean (±SD) AGD of boys with hypospadias was 67 ± 1.2 versus 73 ± 1 mm for boys with normal genitals (P = 0.002). In these age-unmatched patient groups, there were also differences in age, height and weight (P = 0.0001, 0.0002 and 0.0004, respectively). After age matching (all <2 years of age), boys with hypospadias (n= 26) still featured a shorter AGD than boys with normal genitals (n= 26; 62 ± 2 versus 68 ± 2 mm respectively, P = 0.033) but the differences in age, height and weight were no longer significant.
CONCLUSIONS: In humans, hypospadias may indeed be associated with reduced AGD. Additional studies are needed to corroborate these preliminary findings and to determine their etiology.