Pseudohypoparathyroidism: a rare but important cause of hypocalcaemia. (22nd January 2013)

• Record Type: Journal Article
• Authors: Chong, Pui Lin; Meeking, Darryl R
• Is Part Of: BMJ case reports. Volume 2013
• Publication Date: 2013-01-22
• Subjects: Medicine -- Case studies -- Periodicals; 610.5
• DOI: 10.1136/bcr-2012-008040
• Languages: English
• ISSNs: 1757-790X

Abstract

Abstract : 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.