Low PTH (hypoparathyroidism) |
Impaired synthesis or secretion of PTH |
Genetic - DiGeorge syndrome (MIM#188400, MIM #601363)
- Genetic mutations interfering with the production of PTH (autosomal dominant, autosomal recessive)
- HDR syndrome (hypoparathyroidism, deafness, renal anomaly, MIM #146255)
- Sanjad-Sakati syndrome (MIM#241410) or Kenny-Caffey syndrome (MIM #244460, MIM #127000)
- Mutations of the CaSR and related proteins (autosomal dominant hypocalcemia, MIM#601198; MIM#615361)
- Mutations interfering with parathyroid gland development (X-linked; MIM #307700)
- Mitochondrial disorders (eg, MELAS syndrome, MIM #540000; Kearns-Sayre syndrome, MIM #530000; mitochondrial trifunctional protein deficiency, MIM #609015)
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Autoimmune |
Other - Parathyroid or thyroid gland surgery
- Infiltration of parathyroid gland (eg, iron overload)
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High PTH |
Deficient calcium intake or intestinal absorption |
Deficient vitamin D intake, intestinal absorption and/or dermal synthesis |
Defects in vitamin D metabolism |
Hepatic dysfunction - Severe liver disease
- Drugs that increase cytochrome P450 activity, which accelerate catabolism of vitamin D to inactive metabolites (eg, anticonvulsant drugs, isoniazid, and rifampin)
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Kidney function impairment |
Genetic disorders - 25-hydroxylase deficiency (MIM#600081)
- 1-alpha-hydroxylase deficiency (MIM#264700, previously known as vitamin D-dependent rickets type 1 or pseudovitamin D-deficient rickets)
- Increased catabolism of vitamin D (MIM #619073, due to gain-of-function variants in the CYP3A4 gene)
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Defects in vitamin D action |
Hereditary resistance to vitamin D (MIM#277440, previously known as vitamin D-dependent rickets type 2) |
End-organ resistance to PTH (pseudohypoparathyroidism) |
Type 1 (1a MIM #103580, 1b MIM #603233, and 1c MIM #612462) |
Type 2 (MIM %203330) |
Miscellaneous |
Hungry bone syndrome |
Osteopetrosis |
Sepsis or acute severe illness |
Hyperphosphatemia |
Alkalosis |
Intravenous products with citrate or lactate |
Pancreatitis |
Fluoride poisoning |
Drugs – Bisphosphonates, denosumab, calcimimetics (cinacalcet), foscarnet, and some chemotherapeutic drugs |
Hypomagnesemia (including genetic disorders, MIM #602014 and others) |