MONDO_0008234 (multiple endocrine neoplasia type 2A) is an autosomal dominant tumor predisposition disorder caused by pathogenic variants in the RET gene, characterized by an increased risk of medullary thyroid carcinoma, pheochromocytoma, and hyperparathyroidism. Also known as: MEA type 2a, MEA type II, MEN2A, RET-related multiple endocrine neoplasia type 2A, Sipple syndrome, men 2A, men type 2a, men type II.