Endocrine Abstracts

Introduction: HDR syndrome, is a rare, genetic syndrome characterized by hypoparathyroidism sensorineural deafness and renal disease. Mutations in GATA binding protein 3 (GATA3), a gene localized to the chromosome region 10p14-15, have been detected in families affected by the syndrome.

Case report: This is a 30 year old lady who was referred to the endocrine services with symptoms of generalized fatigue, mouth numbness and tingklining. Her past medical history include bilateral sensorineural deafness with hearing aids. In addition she has inborn unilateral renal agenesis. There was no previous history of calcium metabloism disorder. Her father had bilateral sensorineural deafness. Biochemical evaluation showed low calcium level, high phosphate level, low parathyroid hormone level and mild renal impairment. Providing her clinical presentation with hypocalcaemia, sensorinural deafness and renal impairment, HDR syndrome was suspected and genetic analysis was undertaken and showed mutations in GATA binding protein 3 (GATA3) which confirmed HDR syndrome.

Discussion: The HDR syndrome, also known as Barakat syndrome, is an autosomal dominant disorder caused by germline inactivating mutations of the GATA3 gene.1,2 GATA3 encodes a transcription factor that is involved in embryonic development of the parathyroid glands, inner ear and kidneys.3 The HDR syndrome has wide phenotypic variability. Hypoparathyroidism has a variable age of onset and is characterized by symptomatic or asymptomatic hypocalcaemia with undetectable or low serum PTH levels. Renal anomalies in HDR syndrome are also heterogeneous and include renal dysplasia, hypoplasia, or aplasia, and vesicoureteric reflux.

Conclusion: Diagnosis of HDR syndrome is still challenging, but clinicians should consider it in their differential diagnosis with a wide range of clinical manifestations including hypocalcemia, renal abnormalities and deafness.