CHARGE Syndrome
Characteristics
- Coloboma
- Unilateral or bilateral coloboma of the iris, retina-choroid, and/or disc with or without microphthalmos (80%-90% of individuals)
- Heart Defects (75-85%)
- Almost every type of congenital heart defect has been described including VSD, ASD, PDA
- Many have multiple and complex defects: aortic arch defects, shunts, AV canal and others. Cardiology of CHARGE
- Atresia of the choanae
- Unilateral or bilateral choanal atresia or stenosis (50%-60%)
- Retarded growth and development
- Growth deficiency (70%-80%)
- Developmental Delay
- Genital abnormalities
- Cryptorchidism in males and hypogonadotrophic hypogonadism in both males and females
- Ear anomalies
- Abnormal outer ears, ossicular malformations, Mondini defect of the cochlea and absent or hypoplastic semicircular canals (>90%)
- impaired hearing and/or swallowing problems (70-80%)
- Other problems
- Cranial nerve dysfunction resulting in hyposmia or anosmia, unilateral or bilateral facial palsy (40%), swollowing problems (70-90%)
- Orofacial clefts (15%-20%)
- Tracheoesophageal fistula (15%-20%)
Major Characteristics: More specific for CHARGE
- Ocular Coloboma
- Choanal atresia or stenosis
- Hearing loss
- Cranial nerve abnormalities
Minor Characteristics: Less specific for CHARGE, more important if many of these present
- Heart Defects
- Growth and Developmental Delay
- Cleft Lip and or Palate
- Genital abnormalities
- Tracheoesophageal fistula
Incidence
- Estimated to occur in 1:8,500 to 1:10,000 people
Genetics
- Inheritance Pattern
- Autosomal Dominant, most with new mutation
- Genes
- CHD7 found to cause more than 50% of cases
- CHD7 gene product regulates gene expression by chromatin remodeling.
- CHD7 mutations can have varied and widespread effects during embryonic development
Ocular Considerations
- Retinal Detachment Risk: 8% in a study by Keech and others-1997
- Vision may be affected or not depending upon the position and extent of the coloboma
- Trial of ambylopia treatment may be warranted
- Cataract may accompany coloboma