In our cohort of 318 AIP (and GPR101) mutation-negative FIPA families, 21% have homogenous acromegaly (representing 46% of the 147 homogeneous AIP negative families) and 32% has heterogenous FIPA with at least member with acromegaly (59% of the 171 heterogenous FIPA kindreds). The gene discussed is AIP; the disease is acromegaly.