Pituitary adenomas represent a group of functionally diverse neoplasms with 
relatively high prevalence in the general population. Most occur sporadically, 
but inherited genetic predisposing factors are increasingly recognized. Familial 
isolated pituitary adenoma is a recently defined clinical entity, and is 
characterized by hereditary presentation of pituitary adenomas in the absence of 
clinical and genetic features of syndromic disease such as multiple endocrine 
neoplasia type 1 and Carney complex. Familial isolated pituitary adenoma is 
inherited in an autosomal dominant manner and accounted for approximately 2-3% 
of pituitary tumors in some series. Germline mutations in the aryl-hydrocarbon 
interacting protein gene are identified in around 25% of familial isolated 
pituitary adenoma kindreds. Pituitary adenomas with mutations of the 
aryl-hydrocarbon interacting protein gene are predominantly somatotropinomas and 
prolactinomas, but non-functioning adenomas, Cushing disease, and thyrotropinoma 
may also occur. These tumors may present as macroadenomas in young patients and 
are often relatively difficult to control. Furthermore, recent evidence 
indicates that aryl-hydrocarbon interacting protein gene mutations occur in >10% 
of patients with sporadic macroadenomas that occur before 30 years of age, and 
in >20% of children with macroadenomas. Genetic screening for aryl-hydrocarbon 
interacting protein gene mutations is warranted in selected high-risk patients 
who may benefit from early recognition and follow-up.