LINKAGE OF THE ANGIOTENSINOGEN GENE LOCUS TO HUMAN ESSENTIAL-HYPERTENSION IN AFRICAN CARIBBEAN

The renin-angiotensin system regulates blood pressure and sodium balan ce. The angiotensinogen gene which encodes the key substrate within th is system has been linked to essential hypertension in White Europeans , It has been suggested that people of West African ancestry may have a different genetic basis for hypertension, In this study we have test ed whether there is linkage of the angiotensinogen gene to essential h ypertension in African Caribbeans from St. Vincent and the Grenadines. DNA from 63 affected sibling pairs with hypertension was tested for l inkage by analyzing whether there was excess allele sharing among sibl ings genotyped using an angiotensinogen dinucleotide repeat sequence, There was significant support for linkage (T = 3.07, P = 0.001) and as sociation of this locus to hypertension (X(2) = 50.2, 12 degrees of fr eedom, P much less than 0,001),A DNA polymorphism which alters methion ine to threonine at position 235 (M235T) within the angiotensinogen pe ptide has been associated previously with hypertension. However, we fo und no association of this variant with hypertension in this study. Th ese findings provide support for linkage and association of the angiot ensinogen locus to hypertension in African Caribbeans and suggest some similarities in the genetic basis of essential hypertension in popula tions of different ethnicity,