CHD7 gene

Overview

Gene (OMIM No.)
Function of gene/protein
  • Protein: chromodomain helicase DNA binding protein 7
  • Regulates the activity of genes by altering the structure of DNA (through chromatin remodelling)
  • Expressed in developing eyes, inner ears and brain
Clinical phenotype
(OMIM phenotype no.)
  • CHARGE syndrome (#214800)
  • Hypogonadotropic hypogonadism 5 with or without anosmia (#612370)
Inheritance
  • Autosomal dominant
Ocular features
Systemic featuresCHARGE syndrome
  • Heart defects (tetralogy of Fallot, atrial/ventricular septal defect, double-outlet right ventricle, patent ductus arteriosus)
  • Choanal atresia
  • Growth retardation and intellectual disability
  • Genital anomalies (micropenis, cryptorchidism, hypoplastic labia)
  • Ear anomalies and deafness (sensorineural or mixed sensorineural and conductive)
Other associated features of CHARGE syndrome
  • Craniofacial (microcephaly, square face, malar flattening, micrognathia, facial asymmetry, cleft lip/palate)
  • Anosmia
  • Gastrointestinal (tracheoesophageal fistula, oesophageal atresia, duodenal atresia, anal atresia, anal stenosis, poor feeding, chewing/swallowing difficulties)
  • Renal (horseshoe kidney, hydronephrosis)
  • Immunologic (thymic hypoplasia or aplasia, T cell defect, lymphopenia)
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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Additional information

Due to overlapping features of anosmaia and hypogonadism, Kim et al concluded that the hypogonadotrophic hypogonadism 5 with/without anosmia phenotype is a milder phenotype compared to CHARGE syndrome due to milder variants of the CHD7 gene.[4]

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References

  1.  Källén K, Robert E, Mastroiacovo P, Castilla EE, Källén B. CHARGE Association in newborns: a registry-based study. Teratology. 1999;60(6):334‐343
  2.  Kita Y, Nishiyama M, Nakayama KI. Identification of CHD7S as a novel splicing variant of CHD7 with functions similar and antagonistic to those of the full-length CHD7L. Genes Cells. 2012;17(7):536‐547
  3.  Pagon RA, Graham JM Jr, Zonana J, Yong SL. Coloboma, congenital heart disease, and choanal atresia with multiple anomalies: CHARGE association. J Pediatr. 1981;99(2):223‐227
  4.  Kim HG, Kurth I, Lan F, et al. Mutations in CHD7, encoding a chromatin-remodeling protein, cause idiopathic hypogonadotropic hypogonadism and Kallmann syndrome. Am J Hum Genet. 2008;83(4):511‐519

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Updated on November 30, 2020

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