Barakat syndrome

Barakat syndrome
Classification and external resources
OMIM	146255

Barakat syndrome, is a rare disease characterized by hypoparathyroidism, sensorineural deafness and renal disease, and hence also known as HDR syndrome. It was first described by Amin J. Barakat et al. in 1977.^[1]

Presentation

It is a genetic developmental disorder^[2] with clinical diversity 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, pelvicalyceal deformity, vesicoureteral reflux, chronic kidney disease, hematuria, proteinuria and renal scarring.

Genetics

The defect in the majority of cases has mapped to chromosome 10p (Gene Map Locus: 10pter-p13 or 10p14-p15.1). Haploinsufficiency (deletions) of zinc-finger transcription factor GATA3 or mutations in the GATA3 gene^[3] appear to be the underlying cause of this syndrome. It causes the failure in the specification of prosensory domain and subsequently leads to increased cell death in the cochlear duct thus causing deafness.^[4] Since the spectrum of phenotypic variation in affected patients is quite large, Barakat (HDR) syndrome probably arises as a low penetrance haploinsufficient disorder in which the patients' genetic background plays a major role in the severity of the disease.

Inheritance is probably autosomal dominant.

Diagnosis

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 urinary tract abnormalities. Management consists of treating the clinical abnormalities at the time of presentation. Prognosis depends on the severity of the kidney disease.

Epidemiology

The frequency is unknown, but the disease is considered to be very rare.^[5]

References

↑ Barakat AY, D'Albora JB, Martin MM, Jose PA (July 1977). "Familial nephrosis, nerve deafness, and hypoparathyroidism". J. Pediatr. 91 (1): 61–4. doi:10.1016/S0022-3476(77)80445-9. PMID 874665.
↑ William B. Coleman (9 February 2010). Essential Concepts in Molecular Pathology. Academic Press. pp. 297–. ISBN 978-0-12-374418-0. Retrieved 5 December 2010.
↑ Bernardini L, Sinibaldi L, Capalbo A; et al. (July 2009). "HDR (Hypoparathyroidism, Deafness, Renal dysplasia) syndrome associated to GATA3 gene duplication". Clin. Genet. 76 (1): 117–9. doi:10.1111/j.1399-0004.2009.01170.x. PMID 19659764.
↑ Luo, X.-j.; Deng, M.; Xie, X.; Huang, L.; Wang, H.; Jiang, L.; Liang, G.; Hu, F.; Tieu, R.; Chen, R.; Gan, L. (10 May 2013). "GATA3 controls the specification of prosensory domain and neuronal survival in the mouse cochlea". Human Molecular Genetics 22 (18): 3609–3623. doi:10.1093/hmg/ddt212. PMID 23666531.
↑ Ranjbar-Omrani, G; Zamiri, N; Sabayan, B; Mohammadzadeh, A (May 2008). "Concomitant hypoparathyroidism, sensorineural deafness, and renal agenesis: a case of Barakat syndrome.". Archives of Iranian medicine 11 (3): 337–40. PMID 18426329.

External links

Gaynor KU, Grigorieva IV, Nesbit MA; et al. (October 2009). "A missense GATA3 mutation, Thr272Ile, causes the hypoparathyroidism, deafness, and renal dysplasia syndrome". J. Clin. Endocrinol. Metab. 94 (10): 3897–904. doi:10.1210/jc.2009-0717. PMID 19723756.

Genetic disorder, protein biosynthesis: Transcription factor/coregulator deficiencies

(1) Basic domains

1.2	Feingold syndrome Saethre–Chotzen syndrome

1.3	Tietz syndrome

(2) Zinc finger
DNA-binding domains

2.1	(Intracellular receptor): Thyroid hormone resistance Androgen insensitivity syndrome PAIS MAIS CAIS Kennedy's disease PHA1AD pseudohypoaldosteronism Estrogen insensitivity syndrome X-linked adrenal hypoplasia congenita MODY 1 Familial partial lipodystrophy 3 SF1 XY gonadal dysgenesis

2.2	Barakat syndrome Tricho–rhino–phalangeal syndrome

2.3	Greig cephalopolysyndactyly syndrome/Pallister–Hall syndrome Denys–Drash syndrome Duane-radial ray syndrome MODY 7 MRX 89 Townes–Brocks syndrome Acrocallosal syndrome Myotonic dystrophy 2

2.5	Autoimmune polyendocrine syndrome type 1

(3) Helix-turn-helix domains

3.1	ARX Ohtahara syndrome Lissencephaly X2 MNX1 Currarino syndrome HOXD13 SPD1 Synpolydactyly PDX1 MODY 4 LMX1B Nail–patella syndrome MSX1 Tooth and nail syndrome OFC5 PITX2 Axenfeld syndrome 1 POU4F3 DFNA15 POU3F4 DFNX2 ZEB1 Posterior polymorphous corneal dystrophy Fuchs' dystrophy 3 ZEB2 Mowat–Wilson syndrome

3.2	PAX2 Papillorenal syndrome PAX3 Waardenburg syndrome 1&3 PAX4 MODY 9 PAX6 Gillespie syndrome Coloboma of optic nerve PAX8 Congenital hypothyroidism 2 PAX9 STHAG3

3.3	FOXC1 Axenfeld syndrome 3 Iridogoniodysgenesis, dominant type FOXC2 Lymphedema–distichiasis syndrome FOXE1 Bamforth–Lazarus syndrome FOXE3 Anterior segment mesenchymal dysgenesis FOXF1 ACD/MPV FOXI1 Enlarged vestibular aqueduct FOXL2 Premature ovarian failure 3 FOXP3 IPEX

3.5	IRF6 Van der Woude syndrome Popliteal pterygium syndrome

(4) β-Scaffold factors
with minor groove contacts

4.2	Hyperimmunoglobulin E syndrome

4.3	Holt–Oram syndrome Li–Fraumeni syndrome Ulnar–mammary syndrome

4.7	Campomelic dysplasia MODY 3 MODY 5 SF1 SRY XY gonadal dysgenesis Premature ovarian failure 7 SOX10 Waardenburg syndrome 4c Yemenite deaf-blind hypopigmentation syndrome

4.11	Cleidocranial dysostosis

(0) Other transcription factors

0.6	Kabuki syndrome

Ungrouped

Transcription coregulators

Coactivator:	CREBBP Rubinstein–Taybi syndrome

Corepressor:	HR (Atrichia with papular lesions)

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