Possible association of MN locus haplotypes with essential hypertension.

Five multigenerational kindreds with familial hypertension were typed for human leukocyte antigen (HLA) and blood group antigens to investigate genetic factors that influence variability in blood pressure. Pedigree analysis revealed that children of matings in which both parents were hypertensive had a significantly greater risk of hypertension than children of matings in which one parent or neither parent was hypertensive. Blood types N and MN were abnormally distributed among hypertensive as compared with normotensive members of white but not black families. The distribution of ABO and Rh types was not significantly different between hypertensive and normotensive siblings. When all possible pairings of siblings were examined for HLA haplotype sharing, abnormal distributions were observed among hypertensive sib pairs whereas the expected mendelian segregation was observed among hypertensive-normotensive sib pairs and normotensive-normotensive sib pairs. These results suggest the genetic factors controlling variation in blood pressure may include loci in the region of the MN locus on chromosome 4 and, possibly, the major histocompatibility complex on chromosome 6.