A novel genetic locus for low renin hypertension: familial hyperaldosteronism type II maps to chromosome 7 (7p22)

Familial hyperaldosteronism type II (FH-II) is caused by adrenocortical hyp erplasia or aldosteronoma or both and is frequently transmitted in an autos omal dominant fashion. Unlike FH type I (FI-I-I), which results from fusion of the CYP11B1 and CYP11B2 genes, hyperaldosteronism in FH-II is not gluco corticoid remediable. A large family with FH-II was used for a genome wide search and its members were evaluated by measuring the aldosterone:renin ra tio. In those with an increased ratio, FH-II was confirmed by fludrocortiso ne suppression testing. After excluding most of the genome, genetic linkage was identified with a maximum two point lod score of 3.26 at theta =0, bet ween FH-II in this family and the polymorphic markers D7S511, D7S517, and G ATA24F03 on chromosome 7,a region that corresponds to cytogenetic band 7p22 . This is the first identified locus for FH-II; its molecular elucidation m ay provide further insight into the aetiology of primary aldosteronism.