ANGIOTENSIN I-CONVERTING ENZYME GENE POLYMORPHISM AND SALT SENSITIVITY IN ESSENTIAL-HYPERTENSION

We undertook the present study in 66 Japanese patients with essential hypertension to identify genetic factors associated with salt sensitiv ity. Patients were classified into salt-sensitive or sail-resistant gr oups on the basis of changes in their mean blood pressures from a week of a low salt diet (50 mmol/d) to a week of a high salt diet (340 mmo l/d). Salt sensitivity and resistance were studied in relation to a 28 7-bp insertion/deletion (I/D) polymorphism of the angiotensin I-conver ting enzyme gene detected by a polymerase chain reaction method and th e haptoglobin phenotype determined by polyacrylamide gel electrophores is. Patients with the angiotensin I-converting enzyme gene genotype II were more apt to be salt sensitive than patients with the ID and DD g enotypes, although plasma renin activity was similar in each group. Th e frequency of the I allele in the salt-sensitive group was significan tly higher than that in the salt-resistant group (chi(2)=7.4, odds rat io=2.78). However, there was no significant relation ship between hapt oglobin phenotype and salt sensitivity. These data suggest that an I/D polymorphism of the angiotensin I-converting enzyme gene is a genetic factor associated with salt sensitivity of blood pressure independent ly of plasma renin activity in Japanese patients with essential hypert ension.