P-424: The 460Trp [alpha]-adducin allele and high sodium-lithium countertransport are associated with high blood pressure and increased body fat

In previous work, we showed by univariate mixture analysis that the population distribution of sodium-lithium countertransport (SLC) is composed of two subgroups. In this study we analyzed these two subgroups in order to test a possible interaction between the α-adducin gene and SLC on blood pressure and body fat.Methods: The present study was conducted as part of the ongoing GenNet study of the Family Blood Pressure Program. We examined 225 subjects (105 males, 120 females; age 13-73 yrs) in whom α adducin genotype and SLC measurements were available. Subjects were classified as normal or high SLC (by mixture analysis) and as GG or 460Trp (homozygous TT + heterozygous GT). Blood pressure and body fat were measured in all subjects. Blood for SLC was assayed as previously reported from our laboratory. Statistical analyses were performed with software of the SAS Institute. Data was adjusted for age and gender and expressed as mean ± SEM. Significance was accepted at P < 0.05.Results: As shown in the Table, subjects were characterized by normal or high SLC and the presence or absence of the 460Trp. Subjects with high SLC and the 460Trp allele had higher blood pressure and body fat than those with normal SLC and 460Trp. No such differences were observed in subjects with GG genotype (table). Subjects with 460Trp and high SLC were 3.77 times more likely to have fat mass > 50th percentile than those with 460Trp and low SLC (X2 = 8.15, P = 0.005, 95% CI 1.15-9.45).Conclusion: This study shows a significant interaction between the α-adducin 460Trp mutation and high SLC on blood pressure and body fat in healthy subjects.