HM Luk, IFM Lo, TMF Tong, KKS Lai, STS Lam

Abstract

Objective: Pseudohypoparathyroidism type 1b is a rare genetic endocrine disease. We would like to increase awareness of this condition and highlight what clinical geneticists can contribute in the patient management. Method: Case report and literature review. Case presentation: A 10-year-old boy was referred for suspected pseudohypoparathyroidism with parathyroid hormone resistance on biochemical investigation. Physical examination showed no features of Albright hereditary osteodystrophy and normal intelligence. There was no family history of endocrine or developmental problem. Based on above, the diagnosis of pseudohypoparathyroidism type 1b was suspected. It was subsequently confirmed by epigenetic change over GNAS gene using methylation genetic study. Conclusion: Pseudohypoparathyroidism 1b is a rare endocrine disease caused by epigenetic change in GNAS gene. All patients with parathyroid hormone resistance should be referred to the clinical geneticist for proper assessment, genetic testing, and genetic counselling.