Clinical review 109: Contrasting paradigms for hereditary hyperfunction of endocrine cells.

Abstract

Hereditary endocrine hyperfunction is categorized here as neoplastic or not neoplastic. The disorders and their mutated genes are subdivided further by hyperfunctional hormone secretory tissue (Table 1). For example, the parathyroids hyperfunction in at least three hereditary neoplastic syndromes [multiple endocrine neoplasia type 1 (MEN1), multiple endocrine neoplasia type 2a (MEN2a), and hyperparathyroidism-jaw tumor syndrome (HPT-JT)], each associated with one distinct gene (1, 2) or locus (3–5). Alternately, the parathyroids can be overactive in two hereditary non-neoplastic syndromes–familial hypocalciuric hypercalcemia (FHH) or neonatal severe primary hyperparathyroidism (NSHPT). Either is usually caused by mutations of the CaSR gene (6–9); two other undiscovered genes account for FHH in a few families (10, 11). A similar classification dichotomy applies to hereditary hyperfunction of pancreatic islet b cells (1, 12–17), of thyrocytes (18–23), or of Leydig cells (19, 24–26) (Table 1). For didactic purposes, this analysis omits endocrine tissue without separate hereditary disorders in each of the two categories. For example, hereditary pheochromocytoma may arise from neoplasia with germline mutation of VHL (12), RET (2), or NF1, but apparently not from non-neoplastic processes. This analysis also excludes dysfunctions outside the hyperfunctional endocrine tissue (for example, hereditary hyperandrogenism can be caused by activation of the CRF/ACTH axis secondary to defective cortisol synthesis).