<s>[INST] <<SYS>> This is a medical question of type : frequency <</SYS>> How many people are affected by familial hyperaldosteronism ? [/INST] The prevalence of familial hyperaldosteronism is unknown. Familial hyperaldosteronism type II appears to be the most common variety. All types of familial hyperaldosteronism combined account for fewer than 1 out of 10 cases of hyperaldosteronism. </s>