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 (Pless than or equal to.00011). 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 (Pless than or equal to.003, Pless than or equal to002, respectively), while the 188 bp allele was associated with a higher resting systolic blood pressure (SBP) (Pless than or equal to.02), and greater hemodynamic response to stress with increasing BMI (Pless than or equal to.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.