. Author manuscript; available in PMC: 2020 Oct 1.

Published in final edited form as: Curr Osteoporos Rep. 2019 Oct;17(5):324–332. doi: 10.1007/s11914-019-00529-7

Table 2:

Mechanisms of osteomalacia

PTH-mediated Disorders

Disease	Mechanism	Genetic vs Acquired

Vitamin D Deficiency	Decreased 25-OH₂-D by poor intake	Acquired

Renal Insufficiency	Decreased 1-alpha hydroxylase activity leads to decreased active 1,25-OH₂-D	Acquired

Hepatic Insufficiency	Decreased 25-hydroxylation of vitamin D in the liver leads to decreased active 1,25-OH₂-D	Acquired

FGF23-mediated Disorders

Disease	Mechanism	Genetic vs Acquired

Tumor-induced osteomalacia	Mesenchymal tumor autonomously secretes FGF23	Acquired

X-linked hypophosphatemic rickets	Mutation in PHEX	Genetic

Autosomal Dominant Hypophosphatemic Rickets	Mutation in FGF23 causes decreased cleavage and inactivation	Genetic

Autosomal Recessive Hypophosphatemic Rickets (Type 1 and 2)	Mutations in DMP1 and ENPP1	Genetic

Renal-mediated Disorders

Disease	Mechanism	Genetic vs Acquired

Fanconi Anemia	Renal proximal tubule damage	Genetic or Acquired

Hereditary Hypophosphatemic Rickets with Hypercalciuria	Mutation of SLC23A3 (renal phosphate channel)	Genetic