Familial pituitary adenomas occur in multiple endocrine neoplasia type 1, Carney 
complex, as well as in familial isolated pituitary adenoma syndrome. Familial 
isolated pituitary adenoma syndrome is an autosomal dominant disease with 
incomplete penetrance. Pituitary adenomas occur in familial setting but without 
any other specific tumors. In 20-40% of families with this syndrome, mutations 
have been identified in the aryl hydrocarbon receptor interacting protein gene 
while in the rest of the families the causative gene or genes have not been 
identified. Families carrying aryl hydrocarbon receptor interacting protein gene 
mutations have a distinct phenotype with younger age at diagnosis and a 
predominance of somatotroph and lactotroph adenomas. Germline mutations of the 
aryl hydrocarbon receptor interacting protein gene can be occasionally 
identified in usually young-onset seemingly sporadic cases. Genetic and clinical 
testing of relatives of patients with aryl hydrocarbon receptor interacting 
protein gene mutations can lead to earlier diagnosis and treatment at an earlier 
stage of the pituitary tumor.