The differential diagnosis of hypocalcemia is broad. The most common cause of hypocalcemia is inadvertent postsurgical hypoparathyroidism.
Autosomal Dominant hypocalcemia
An activating mutation of CASR gene results in a shift in the set point of CASR. As a consequence, PTH is not released at calcium concentration that normally triggers PTH release.
- Increased urinary calcium excretion
- Asymptomatic genetic condition
Pseudohypoparathyroidism
Mutations in the GNAS gene leads to end organ resistance to the effects of parathyroid hormones
- Low calcium, high phosphate and elevated PTH levels
Autoimmune polyglandular syndrome type 1
This condition is also known as Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) syndrome
- Mutations in the AIRE gene (typically expressed in parathyroid glands, pancreas, and adrenal cortex)
Wilson disease
Mutations in the ATP7B gene (encodes hepatic copper transporter). As a consequence, there is a defect in cellular copper transport. This leads to the accumulation of copper in various tissues (including the parathyroid glands)
References
Pepe J, Colangelo L, Biamonte F, Sonato C, Danese VC, Cecchetti V, Occhiuto M, Piazzolla V, De Martino V, Ferrone F, Minisola S, Cipriani C. Diagnosis and management of hypocalcemia. Endocrine. 2020 Sep;69(3):485-495.