Endocrine Abstracts

Introduction: Pseudohypoparathroidism (PHP) is a condition mimics hypoparathyroidism biochemically with a hypocalcemia and hyperphosphatemia but differentiates from it an elevated parathyroid hormone (PTH) levels. PHP characterized by targeted organ unresponsiveness to PTH and mainly subdivided two groups. PHP type 1a an autosomal dominant disease related to mutations of GNAS1. This subtype has biochemical findings and characteristic somatic phenotype known as Albright Hereditary Osteodystrophy (AHO). AHO include short stature, round face, brachydactyly, shortened metatarsals, subcutaneous ossifications and reduced intelligence. PHP type 1b has laboratory findings but do not has phenotype of AHO. This disorder caused by methylation defects of GNAS1 regulatory region. We present a patient who was detected PHP while following for epilepsy.

Case report: A 17 years old male patient referred to endocrinology clinic with paresthesias of the hands. He had under treatment due to epilepsy for 3 years. He had normal mental activity and phenotypic features. His family history had no specialty. His laboratory examination revealed hypocalcemia and hyperphosphatemia with a calcium level 7.4 mg/dl (reference range, 8.5–10.5 mg/dl), phosphorus 6.8 mg/dl (reference range, 2.5–4.5 mg/dl), albumin 4.4 g/dl (reference range, 3.5–5.2 g/dl), magnesium 2.06 mg/dl (reference range, 1.8–2.6 mg/dl), 25 hydroxyvitamin D (25 OHD) 64.3 ng/ml (reference range, 30–70 ng/ml) and PTH 115 pg/ml (reference range, 15–65 pg/ml). His rest of the laboratory findings and ophthalmic examination were normal. Brain computed tomography scan showed basal ganglia calcifications. Calcitriol and calcium supplements were started to patient whose biochemical findings support PHP diagnosis. Genetic testing of the patient did not show GNAS coding region mutation and we planned methylation study in terms of methylation abnormality in GNAS regulatory region.

Conclusion: PHP is an uncommon cause of hypocalcemia. Blood electrolytes must be called to mind in case of epilepsy or neurological evidence. Early diagnosis and treatment of PHP prevent complications.