Barakat syndrome

Barakat syndrome, also known as HDR syndrome, was first described by Barakat et al in 1977 and is an inherited condition characterized by hypoparathyroidism, sensorineural deafness and renal disease. Patients usually present with hypocalcaemia, tetany, or afebrile convulsions at any age. Hearing loss is usually bilateral and may range from mild to profound impairment. Renal disease includes nephrotic syndrome, cystic kidney, renal dysplasia, hypoplasia or aplasia, pevicalyceal deformity, vesicoureteral reflux, chronic renal failure, hematuria, proteinuria and renal scarring. The frequency is unknown, but the disease is considered to be very rare.

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The defect is on chromosome 10p (Gene Map Locus: 10p15, 10p15.1-p14), with haploinsufficiency or mutation of the GATA3 gene being the underlying cause. Inheritance is probably autosomal dominant. A thorough diagnosis should be performed on every affected individual, and siblings should be studied for deafness, parathyroid and renal disease. The syndrome should be considered in infants who have been diagnosed prenatally with a chromosome 10p defect, and those who have been diagnosed with well defined phenotypes of renal tract abnormalities. Management consists of treating the clinical abnormalities at the time of presentation. Prognosis depends on the severity of the renal disease.

References

1. Barakat, AY, D'Albora, JB, Martin, MM, Jose, PA. Familial nephrosis, nerve deafness, and hypoparathyroidism. J. Pediat 1977; 91: 61-4.
2. Bilous, RW, Murty, G, Parkinson, DB, Thakker, RV, Coulthard, MG, Burn, J, Mathias, D, Kendall-Taylor, P. Brief report: Autosomal dominant familial hypoparathyroidism, sensorineural deafness, and renal dysplasia. New Eng J Med 1992; 327: 1069-74.
3. Online Mendelian Inheritance in Man, Johns Hopkins University #146255.
4. Hasegawa,T, Hasegawa, Y, Aso, T.; Koto, S, Nagai, T, Tsuchiya, Y, Kim, K, Ohashi, H, Wakui, K, Fukushima, Y. HDR syndrome (hypoparathyroidism, sensorineural deafness, renal dysplasia) associated with del(10)(p13). Am J Med Genet 1997; 73: 416-8.
5. Nesbit MA, Bowl MR, Harding B, Ali A, Ayala A, Crowe C, Dobbie A, Hampson G, Holdaway I, Levine MA, McWilliams R, Rigden S, Sampson J, Williams AJ, Thakker RV. Characterization of GATA3 mutations in the hypoparathyroidism, deafness, and renal dysplasia (HDR) syndrome. J Biol Chem 2004; 279: 22624-34.
6. Zahirieh A, Nesbit AM, Ali A, Wang K, He N, Stangou M, Bamichas G, Sombolos, K, Thakker RV, Pei Y. Functional analysis of a vovel GATA3 mutation in a family with the hypoparathyroidism, deaness and renal dysplasia (HDR) syndrome. J Clin Endocrinol Metab 2005; 4: 2445-50.