Dysorders with Defective Mineralization

This chapter further discusses bone dysplasias and includes discussion on hypophosphatasia, neonatal severe primary hyperparathyroidism, and hereditary rickets. Each discussion includes major radiographic features, major clinical findings, major laboratory findings, genetics, major differential diagnoses, and a bibliography.

Hyperplasia in glands with hormone excess

Five syndromes share predominantly hyperplastic glands with a primary excess of hormones: neonatal severe primary hyperparathyroidism, from homozygous mutatedCASR, begins severelyin utero; congenital non-autoimmune thyrotoxicosis, from mutatedTSHR, varies from severe with fetal onset to mild with adult onset; familial male-limited precocious puberty, from mutatedLHR, expresses testosterone oversecretion in young boys; hereditary ovarian hyperstimulation syndrome, from mutatedFSHR, expresses symptomatic systemic vascular permeabilities during pregnancy; and familial hyperaldosteronism type IIIA, from mutatedKCNJ5, presents in young children with hypertension and hypokalemia. The grouping of these five syndromes highlights predominant hyperplasia as a stable tissue endpoint and as their tissue stage for all of the hormone excess. Comparisons were made among this and two other groups of syndromes, forming a continuum of gland staging: predominant oversecretions express little or no hyperplasia; predominant hyperplasias express little or no neoplasia; and predominant neoplasias express nodules, adenomas, or cancers. Hyperplasias may progress (5 of 5) to neoplastic stages while predominant oversecretions rarely do (1 of 6; frequencies differP<0.02). Hyperplasias do not show tumor multiplicity (0 of 5) unlike neoplasias that do (13 of 19;P<0.02). Hyperplasias express mutation of a plasma membrane-bound sensor (5 of 5), while neoplasias rarely do (3 of 14;P<0.002). In conclusion, the multiple distinguishing themes within the hyperplasias establish a robust pathophysiology. It has the shared and novel feature of mutant sensors in the plasma membrane, suggesting that these are major contributors to hyperplasia.

Neonatal Severe Primary Hyperparathyroidism (Mim 239200)

Chapter 130 covers neonatal severe primary hyperparathyroidism (MIM 239200), including major clinical findings, radiographic features, and differential diagnoses.