HLA phenotypes were studied in nine Jewish families, originating from Iran, with 18 individuals affected with a selective aldosterone biosynthetic defect and 12 healthy siblings. This disorder is inherited through an autosomal recessive gene and parents were consanguineously related in eight out of nine sibships. Family analysis showed that 18 affected individuals carried 20 different haplotypes and only two patients were homozygous for a haplotype. Yet a peak lod score of 1.128 was obtained for the recombinant fraction of 0.05 and thus linkage to HLA cannot be ruled out.