Nuclear and Mitochondrial DNA are associated with 24 hour Blood Pressure in Afro-Caribbeans.

We have show that the major reason Black Barbadians differ from each other in blood pressure (BP) is due to inherited factors one of which is a mitochondrial genotype. Others have shown that haptoglobin (HP), a nuclear genomic polymorphism, also influences BP. We determined HP genotype, 24 hr BP, 24 hr urine Na+ and ACE levels in 43 Black Barbadians (age: mean 30±11SD). HP and mitochondrial genotype both were associated with 24 hr BP by ANOVA: evening (18-24:00 hr.) (p=0.009) and sleep (0-6:00) (p=0.11) and were positively associated with 24 hr Na+ excretion (P=0.034). In addition hematocrit and ACE were positively correlated (p=0.018). Furthermore, the HP polymorphism was significantly associated with mean arterial pressure (MAP) (p=0.002) in a random sample of 143 blacks in Dominica (age: mean 34.8±12SD). In the Black Barbadians, in which 24 BP was correlated with 24 hr ENa+, the genetic influences on evening and sleep BP and their association with sodium excretion suggests that these genes may be associated with blood pressure raising effects of Na+ in Blacks in the Western Hemisphere. The effect of the HP polymorphism on BP in two distinct African derived populations suggests this chromosomal site (chromosome 16q22.1) may interact with mitochondrial genotype to increase BP.