AIP and prolactin-producing pituitary gland adenoma: As AIP knockout mice are not viable [Lin et al., 2007], and the subjects with the compound heterozygote genotype with the certainly pathogenic R304X mutation are unaffected, this variant is unlikely to have a functional impact, although the patient with a possible phenocopy (small prolactinoma in a young female is not typical of AIP mutation patients) carrying this change makes the status of this variant uncertain.