Pseudohypoparathyroidism: a rare but important cause of hypocalcaemia.
We present a 46-year-old Caucasian lady with symptomatic hypocalcaemia. Investigations revealed markedly raised parathyroid hormone (PTH) levels with vitamin D deficiency. A number of conditions causing secondary hyperparathyroidism were ruled out from her medical history and initial investigations. The main differential diagnoses were vitamin D deficiency and PTH resistance (pseudohypoparathyroidism, PHP). With high-normal serum phosphate and normal alkaline phosphatase, and a lack of symptoms associated with osteomalacia, vitamin D deficiency alone was unlikely to be the cause of hypocalcaemia. Given a normal physical appearance, genetic testing was arranged and confirmed the diagnosis of PHP type Ib. She is currently taking activated vitamin D to maintain calcium homeostasis. PTH resistance is the hallmark of PHP, a rare complex genetic disorder, which can be easily missed resulting in potentially serious consequences.
Academic Department of Diabetes and Endocrinology, Portsmouth Hospitals NHS Trust, Portsmouth, UK. lina.chong@porthosp.nhs.uk
Pui Lin
PL
Chong
Darryl R
DR
Meeking
D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D006996:Hypocalcemia / Q000097:blood / Q000175:diagnosis / Q000209:etiology*; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D011547:Pseudohypoparathyroidism / Q000097:blood / Q000150:complications* / Q000175:diagnosis
D010281:Parathyroid Hormone