A novel mutation in pseudohypoparathyroidism type 1a in a Chinese woman and her son with hypocalcaemia.

Pseudohypoparathyroidism is a rare genetic disorder characterised by end-organ resistance to parathyroid hormone due to a defect of the guanine nucleotide-binding protein alpha that simulates activity of the polypeptide 1 (GNAS) gene. Patients with type 1a pseudohypoparathyroidism display different features of Albright's hereditary osteodystrophy as well as multi-hormone resistance. We describe a Chinese woman and her son, who presented with different symptoms of pseudohypoparathyroidism and clinically manifested different degree of Albright's hereditary osteodystrophy. Genetic study detected a mutation [NM_000516.4(GNAS):c682C>T (p.Arg228Cys)] in the GNAS gene.