CHARGE Syndrome

Clinical Characteristics
Ocular Features: 

Both ocular and systemic abnormalities are highly variable, even within families.  Among the most common ocular features are unilateral or bilateral ocular colobomas (80%).  These involve the iris most frequently but they may extend into the posterior chamber and rarely involve the optic nerve.  A significant number of patients with uveal colobomas have an associated microphthalmia.  The lid fissures often slant downward.  A few patients have congenital cataracts, optic nerve hypoplasia, persistent hyperplastic vitreous, and strabismus.

Systemic Features: 

A wide variety of systemic anomalies have been reported.  Congenital heart defects (primarily septal) and CNS malformations are among the most common features, reported in 85% and 55% respectively.  Tetralogy of Fallot is considered by some to be the most common heart malformation.  Growth and mental retardation are found in nearly 100%.  The pinnae are often set low and hearing loss is common.  Ear anomalies, both internal and external, have been described in 91%, and some degree of conduction and/or sensorineural deafness is present in 62%.  Choanal atresia is found in at least 57% of patients.  This along with cleft palate and sometimes esophageal atresia or reflux often contributes to feeding difficulties which are common in all age groups.  Cranial nerve deficits are seen in 92% of patients and more than one nerve is involved in nearly 3 of 4 patients.  The most common cranial nerve defects involve numbers IX, X, VIII, and V.  Facial palsies are an especially important feature. Hypogonadotropic hypogonadism and underdevelopment of the external genitalia are often seen, especially in males.  One-third of patients have limb anomalies and many have short digits.  The facies is considered by some as characteristic with a square configuration, broad forehead, flat midface, and a broad nasal bridge.

Infant and childhood morbidity is high with feeding difficulties a major cause of death.

Genetics

Many cases occur sporadically but family patterns consistent with autosomal dominant inheritance are common as well.  Advanced paternal age may be a factor in de novo cases.  Sequence variants of multiple types have been reported in the CHD7 gene (8q12.1-q12.2) in more than 90% of familial patients.  The gene product is a DNA –binding protein that impacts transcription regulation via chromatin remodeling.

Kallmann syndrome (hypogonadotropic hypogonadism and anosmia) has been considered to be allelic to CHARGE syndrome but may be the same disorder since mutations in CHD7 are responsible and many patients have other features characteristic of the syndrome described here.

Several patients with classical features of the CHARGE syndrome and de novo mutations in the SEMA3E gene (7q21.11) have also been described.

Treatment
Treatment Options: 

Treatment is lesion dependent but focused on airway, feeding, and cardiac defects at least initially.  Regular ophthalmologic and audiologic evaluations are recommended beginning in infancy.  Evidence for hypogonadism should be evaluated if puberty is delayed.  Nutrition must be monitored especially in those with serious feeding problems.  Hearing devices, with speech, occupational, and education therapy may be required.

References
Article Title: 

References

Janssen N, Bergman JE, Swertz MA, Tranebjaerg L, Lodahl M, Schoots J, Hofstra RM, van Ravenswaaij-Arts CM, Hoefsloot LH. Mutation update on the CHD7 gene involved in CHARGE syndrome. Hum Mutat. 2012 Mar 27.

PubMedID: 22461308

Jongmans MC, van Ravenswaaij-Arts CM, Pitteloud N, Ogata T, Sato N, Claahsen-van der Grinten HL, van der Donk K, Seminara S, Bergman JE, Brunner HG, Crowley WF Jr, Hoefsloot LH. CHD7 mutations in patients initially diagnosed with Kallmann syndrome--the clinical overlap with CHARGE syndrome. Clin Genet. 2009 Jan;75(1):65-71.

PubMedID: 19021638

Jongmans MC, Hoefsloot LH, van der Donk KP, Admiraal RJ, Magee A, van de Laar I, Hendriks Y, Verheij JB, Walpole I, Brunner HG, van Ravenswaaij CM. Familial CHARGE syndrome and the CHD7 gene: a recurrent missense mutation, intrafamilial recurrence and variability. Am J Med Genet A. 2008 Jan 1;146A(1):43-50. 18074359

PubMedID: 18074359

Lalani SR, Safiullah AM, Fernbach SD, Harutyunyan KG, Thaller C, Peterson LE, McPherson JD, Gibbs RA, White LD, Hefner M, Davenport SL, Graham JM, Bacino CA, Glass NL, Towbin JA, Craigen WJ, Neish SR, Lin AE, Belmont JW. Spectrum of CHD7 mutations in 110 individuals with CHARGE syndrome and genotype-phenotype correlation. Am J Hum Genet. 2006 Feb;78(2):303-14.

PubMedID: 16400610

Verloes A. Updated diagnostic criteria for CHARGE syndrome: a proposal. Am J Med Genet A. 2005 Mar 15;133A(3):306-8.

PubMedID: 15666308