RARB gene

Overview

Gene (OMIM No.)
Function of gene/protein
  • Protein: retinoic acid receptor beta
  • Binds to retinoic acid, which is required for normal eye and nasal development during embryogenesis
  • Regulates other genes by binding to specific DNA regions (transcription factor)
Clinical phenotype
(OMIM phenotype no.)
  • Microphthalmia, syndromic 12 (#615524)
Inheritance
  • Autosomal dominant
  • Autosomal recessive
Ocular features
Systemic featuresMain features:
  • Similar to those with STRA6 mutations
  • Pulmonary hypoplasia, agenesis or incomplete lobation
  • Diaphragmatic hernia
  • Facial dysmorphism (broad nasal root and tip, micrognathia, retrognathia, cleft palate)
  • Usually result in termination of pregnancy or early neonatal death; only 1 surviving case with heterozygous mutation reported
Additional features:
  • Cardiac (ventricular septal defects, hypoplastic left atrium, enlarged pulmonary trunk)
  • Genital (cryptorchidism, bicornuate uterus)
  • Learning difficulties
Key investigations
  • B-scan USS to measure axial length to document microphthalmia
  • Electrophysiology
  • MRI brain and orbit
  • Systemic assessment with a paediatrician and other relevant specialists
Molecular diagnosisNext generation sequencing
  • Targeted gene panels (MAC)
  • Whole genome sequencing
ManagementOcularSystemic
  • Multidisciplinary approach
Therapies under research
  • None at present
Further information

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References

  1.  Chitayat, D., Sroka, H., Keating, S., Colby, R. S., Ryan, G., Toi, A., Blaser, S., Viero, S., Devisme, L., Boute-Benejean, O., Manouvrier-Hanu, S., Mortier, G., Loeys, B., Rauch, A., Bitoun, P. The PDAC syndrome (pulmonary hypoplasia/agenesis, diaphragmatic hernia/eventration, anophthalmia/microphthalmia, and cardiac defect) (Spear syndrome, Matthew-Wood syndrome): report of eight cases including a living child and further evidence for autosomal recessive inheritance. Am. J. Med. Genet. 2007;143A: 1268-1281
  2.  Hauksdottir H., Farboud B., Privalsky M.L. Retinoic acid receptors beta and gamma do not repress, but instead activate target gene transcription in both the absence and presence of hormone ligand. Mol. Endocrinol. 2003;17: 373-385
  3.  Srour M, Chitayat D, Caron V, et al. Recessive and dominant mutations in retinoic acid receptor beta in cases with microphthalmia and diaphragmatic hernia [published correction appears in Am J Hum Genet. 2013 Nov 7;93(5):994]. Am J Hum Genet. 2013;93(4):765‐772

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Updated on November 30, 2020
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