The syndrome of hypoparathyroidism, deafness, and renal anomalies

We review the syndrome of hypoparathyroidism, deafness, and renal anomalies (HDR syndrome). The current understanding and relevant literature pertaining to the background, genetic considerations, clinical features, prognosis, and treatment of HDR syndrome are reviewed. The combination of hypoparathyroidism, deafness, and renal anomalies constitutes an unusual syndrome associated most commonly with haploinsufficiency in GATA3, which encodes a transcription factor that binds to the (A/T) GATA (A/G) consensus DNA sequence. Sensorineural hearing loss is the most consistently expressed clinical feature, being present in almost all affected individuals, and the combination of hypoparathyroidism and hearing impairment occurs in well over 90% of those affected, with various renal anomalies being the most heterogeneous feature of the classic triad. We characterize, in tabular form, the individual cases described in the literature and propose a classification scheme based on the presence or absence of renal anomalies. We also include the specific genetic abnormality and renal anomaly associated with each individual case. HDR syndrome is a heterogeneous syndrome most commonly associated with GATA3 haploinsufficiency.