Endocrine Abstracts

Background: HDR syndrome also known by the eponym Barakat syndrome, is a rare, autosomal dominant disorder characterized by the triad of hypoparathyroidism, sensorineural hearing loss, and renal abnormalities. It is caused due to mutation (haploinsufficiency) in GATA3 gene on chromosome 10p with a wide spectrum of phenotypic variations.

Case Presentation: A 33-year-old lady presented to emergency department with an episode of tonic-clonic seizure and a one-week history of paraesthesia-tingling and numbness over face and upper limbs. Her past medical history was notable for sensorineural deafness since childhood. She had a family history of first-degree relatives with congenital deafness and one sibling with renal dysfunction. She had no head and neck surgeries in the past. Laboratory investigations revealed severe hypocalcaemia (adjusted calcium-1.36 mmol/l) along with mild hypomagnesemia, hyperphosphataemia with low vitamin D levels and inappropriately low PTH (1.2 pmol/l). Renal function tests were normal, but CT abdomen revealed a severely contracted left kidney with focal scarring. She was administered intravenous calcium gluconate for correction and then treated with oral calcium with alfacalcidol. The patient was then followed up after four weeks in the clinic where she reported paraesthesia. There was a reduction in calcium level (1.94 mmol/l) requiring further up-titration of calcium and alfacalcidol. A genetic testing was done which showed that she was heterozygous for a pathogenic GATA3 variant. Her performance status improved significantly after correcting calcium levels. The first-degree relatives of the patient were then referred for cascade genetic testing for HDR syndrome.

Conclusion: This case underscores the significance of recognizing diverse clinical expressions in adults with rare genetic disorders with variable penetrance and highlights the necessity of thorough evaluations and interdisciplinary consideration. To better comprehend the varied phenotypic spectrum of HDR Syndrome, further research is essential to refine clinical management and improve patient outcomes.