Endocrine Abstracts

Background: We have recently demonstrated that blood pressure (BP) in children was elevated in males compared to females in the post-pubertal period. We have also shown that the Y chromosome in associated to BP in adult men. Here we report on the effect of 2 polymorphisms on the Y chromosome on BP in male children studied longitudinally both in the pre- and post-pubertal periods.

Methods: We genotyped for 2 SNPs (HindIII +/-; M9 C/G) on the Y chromosome non-recombining region in 80 white and black boys followed prospectively over 5-12 years. Age at peak height velocity (agePHV) was determined for each subject from data on the heights at each visit. Puberty was defined to extend from 2 years prior to the agePHV until the age when growth velocity fell to less than 2 cm/yr. The effect of the polymorphisms on BP was compared using mixed-effects ANOVA adjusted for race, BMI percentile and height. Males with the HindIII(-) polymorphism had a higher BP (systolic 2.6 mm Hg higher, p=0.0471, diastolic 2.3 mm Hg higher, p=0.0496) in the pre- and post-pubertal periods compared to the males with the HindIII(+) polymorphism. The allele type did not affect the rate of change of BP over the pre- and post-pubertal periods. As expected, boy's HindIII status had no effect of predicting history of maternal HT. HindIII allele status was not related to testosterone levels. The other polymorphism tested, M9, did not affect BP in these analyses.

Conclusions: The HindIII(-) allele is associated with significantly higher BP in both the pre- and post-pubertal periods. This polymorphism does not appear to affect testosterone levels, and puberty does not augment the effect on BP. It is possible that boys carrying the HindIII(-) polymorphism are at an increased risk for future cardiovascular disease.