PSEUDOHYPOPARATHYROIDISM Ia TYPE WITH EARLY DEBUT IN SISTERS OF ONE FAMILY

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 Ia pseudohypoparathyroidism have different features of Albright's hereditary osteodystrophy and characteristic phenotype (obesity, round face, short stature, short neck, brachidactyly, etc.), multi-hormone resistance. We describe two sisters (half sibs), who presented with different symptoms of pseudohypoparathyroidism and clinically manifested different degree of Albright's hereditary osteodystrophy. Genetic study detected a mutation p.D190MfsX14 (c.568 571 delGACT), in theGNAS 1 gene (OMIM*139320).