Abstract

ARUS FERNANDEZ, Ana Elena et al. Pseudohypoparathyroidism 1b. Rev Cubana Endocrinol [online]. 2019, vol.30, n.2, e173.  Epub May 26, 2020. ISSN 1561-2953.

Pseudohypoparathyroidism 1b is characterized by isolated resistance to parathormone, in the absence of the typical manifestations of hereditary Albright osteodysphrophy; due to epigenetic alterations of the GNAS locus. It can occur sporadically, or inherited in an autosomal dominant way through the mother. We report the case of a 31-year-old male patient, with history of bone tumors and cerebral calcifications diagnosed at age 14. She came to consultation due to severe dizziness, stiff neck and mouth, difficulty speaking and swallowing, disorientation and perception disorders; he showed normal phenotype and somatometry, and signs of latent tetany (positive Chvostek and Trouseau). Studies have shown hypocalcaemia, hyperphosphatemia, increased levels of parathormone and multiple calcifications in the brain and cerebellum. These findings, pseudohypoparathyroidism 1b is diagnosed confirmed by molecular tests showing alteration in the methylation pattern in the GNAS locus. There were no alterations in the sequencing study of the 13 exons coding for GNAS. It was concluded as a sporadic case in the absence of a family history of hypocalcemia, combined with extensive loss of GNAS gene methylation and no evidence of deletions. This is the first report this disease with molecular study in Cuba.

Keywords : pseudohypoparathyroidism; hypocalcemia; genetic counseling.