Case Report Unrecognized Pseudohypoparathyroidism Type 1A as a Cause of Hypocalcemia and Seizures in a 64-Year-Old Woman Patrizia Del Monte , 1 Carla Micaela Cuttica, 1 Alessandro Marugo, 1 Luca Foppiani , 2 Daniela Audenino, 3 Tomasz Tadeusz Godowicz, 4 Francesca Marta Elli, 5 Giovanna Mantovani , 5 and Emilio Di Maria 6 1 Endocrine Unit, Galliera Hospital, Genoa, Italy 2 Internal Medicine Unit, Galliera Hospital, Genoa, Italy 3 Neurology Unit, Galliera Hospital, Genoa, Italy 4 Neurosurgery Unit, Galliera Hospital, Genoa, Italy 5 Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Endocrinology and Diabetology Unit, Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy 6 Department of Health Sciences, University of Genoa; Medical Genetics Unit, Galliera Hospital, Genoa, Italy Correspondence should be addressed to Patrizia Del Monte; patrizia.del.monte@galliera.it Received 24 October 2018; Accepted 24 December 2018; Published 9 January 2019 Academic Editor: Eli Hershkovitz Copyright © 2019 Patrizia Del Monte et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Pseudohypoparathyroidism type 1A (PHP1A) is usually diagnosed in childhood or early adulthood. We describe the case of a 64- year-old woman admitted to the Neurological Unit for recurrent episodes of loss of consciousness and seizures. Glycemia and ECG were normal, while hypocalcemia was noted. Clinical history revealed carpo-pedal spasm since the age of 30 years, cognitive impairment, hypothyroidism since early adulthood, and menopause at 30 years. She was taking oral calcium and cholecalciferol for chronic hypocalcemia. Physical features suggested Albright’s osteodystrophy. Blood calcium was confrmed low, with increased parathyroid hormone, moderate 25OH-vitamin D defciency, and normal creatinine. Brain CT scan revealed calcifcations of the basal ganglia, cortical and subcortical white matter, and cerebellum. Terapy was switched to oral calcitriol, with normalization of calcium levels; levetiracetam was started and no further seizures occurred. Te clinical diagnosis of PHP1A was confrmed by molecular analysis, which demonstrated the heterozygous c.568 571del mutation of the GNAS gene. Our report illustrates the natural history of a patient with PHP1A, which went undiagnosed until the age of 64 years, with multi-hormonal resistance and clinical sequelae evolving throughout life, and underlines the importance of diagnosing this rare disease, which has a great impact on patients and their family life. 1. Introduction Pseudohypoparathyroidism (PHP) is a rare congenital dis- order, its estimated prevalence being 0.34 - 1.1 in 100.000; it is characterized by impairment of the parathyroid hormone (PTH) signaling pathway, with target organ resistance to the action of PTH [1, 2]. Te term PHP comprises several related and highly heterogeneous diseases with genetic/epigenetic causes [3, 4]. PTH exerts its actions by binding to a trans- membrane G-protein-coupled receptor, activating cAMP formation. Te classical form of PHP, pseudohypoparathy- roidism type 1A (PHP1A), which is associated with Albright’s hereditary osteodystrophy (AHO), is caused by de novo or autosomal dominantly inherited inactivating mutations within the G s -coding GNAS gene (20q13.3; OMIM #139320) [5]. Te maternal allele is the predominant source of G s - expression in the proximal renal tubule, thyroid, pituitary, and gonads, since paternal G s expression is silenced in these tissues; in other tissues, however, G s expression is biallelic. Terefore, an inactivating G s mutation causes Hindawi Case Reports in Endocrinology Volume 2019, Article ID 8456239, 5 pages https://doi.org/10.1155/2019/8456239