A tyrosine hydroxylase microsatellite and hemodynamic response to stress in a multi-ethnic sample of youth.

OBJECTIVE Behavioral stress is believed to have an impact on cardiovascular health. As the rate-limiting enzyme in the pathway for catecholamine synthesis, tyrosine hydroxylase is a candidate gene for variability in cardiovascular function. The aim of this study was to determine whether a relationship exists between a tyrosine hydroxylase microsatellite and resting hemodynamic function, and/or hemodynamic responsivity to laboratory stress. DESIGN Subjects underwent 2 laboratory stressors: a video game challenge and a social competence interview. SETTING The stressors were administered in a laboratory setting. PARTICIPANTS Subjects were 292 10- to 20-year-old normotensive African-American and European-American twin pairs. MAIN OUTCOME MEASURES Blood pressure (BP) and heart rate (HR) were measured at rest and in response to the stressors. RESULTS Chi-square analyses using re-sampling to account for the twin design indicated that allele and genotype frequencies were significantly different between European Americans and African Americans (P < or = .0001). Analyses of variance indicated that the 184 and 199 bp alleles were associated with an attenuation of the hemodynamic response to stress with increasing age (P < or = .003, P < or = .002, respectively), while the 188 bp allele was associated with a higher resting systolic blood pressure (SBP) (P < or = .02), and greater hemodynamic response to stress with increasing BMI (P < or = .02). CONCLUSIONS This study showed that in a multi-ethnic sample of normotensive adolescents, specific alleles of this tyrosine hydroxylase microsatellite were associated with protective or deleterious cardiovascular effects with subjects at rest and responding to stress.