To date 10 different MEN4-associated mutations of CDKN1B have been reported, and the MEN4 patients have parathyroid tumours in association with pituitary adenomas and other tumours of the gonads, adrenals, thyroid and kidney (Thakker, 2013, Pardi et al., 2014). This evidence concerns the gene CDKN1B and pituitary gland adenoma.