Identification of a novel mutation in pseudohypoparathyroidism type Ia in a Chinese family: A case report

INTRODUCTION: Pseudohypoparathyroidism (PHP) indicates a group of rare disorders characterized by end-organ resistance to various hormones, primarily parathyroid hormone (PTH). One of its most common type is PHP-Ia, which is caused by maternally inherited inactivating mutations in GNAS. In this report, we present a Chinese girl with typical features of PHP-Ia and a novel mutation of the GNAS gene. PATIENT CONCERNS: A 9-year-old Chinese girl presented with recurrent epileptic seizure. DIAGNOSIS: Biochemical and imaging findings were consistent with PHP-Ia, including typical Albright hereditary osteodystrophy phenotype (short stature, round face, brachydactyly, and mild mental retardation), PTH resistance (hypocalcemia, hyperphosphatemia, elevated serum PTH, and multiple intracranial calcification) and thyroid stimulating hormone resistance (elevated serum thyroid stimulating hormone). INTERVENTIONS: The patient was given 1α-hydroxylated vitamin D (calcitriol, 0.5 ug/d), calcium carbonate and vitamin D(3) tablets (1.5 g/d, including 600 mg calcium and 125 IU vitamin D(3)). DNA analysis of the GNAS gene was performed for the whole family. OUTCOMES: Investigation of the GNAS gene revealed a novel mutation c.313delG (p.Glu105Lysfs∗7) in the patient, as well as her mother. So the diagnosis of PHP-Ia was confirmed. CONCLUSION: The study further expands the spectrum of known GNAS mutations associated with PHP and lay emphasis on the genetic analysis of GNAS gene for identifying genetic abnormalities as well as making diagnosis and differentiation of various subtypes of PHP.