Analysis of the distribution of erythrocyte sodium lithium countertransport in a sample representative of the general population.

Numerous studies of sodium-lithium countertransport (Na-Li CNT) have reported higher rates in essential hypertensives versus normotensive controls. We studied the distribution and the mode of inheritance of Na-Li CNT using a sample of 238 unrelated individuals and a sample of 245 individuals in 50 pedigrees all sampled from the population at large. The distribution of Na-Li CNT is continuous and bimodal. Our results indicate that there is a large genetic contribution to the distribution of Na-Li CNT. The hypothesis that the effect that causes bimodality is transmitted from generation to generation is supported by the fit to these data of a restricted transmission model with tau 2 = 0.749. We hypothesize that this deviation of tau 2 from its Mendelian expectation may be attributable to heterogeneity in the etiology of the bimodality in the Na-Li CNT distribution in the population at large.