CHARGE syndrome

CHARGE syndrome is caused by mutations in the CHD7 gene in the majority of cases. Almost all mutations in affected individuals are de novo, which means they occur for the first time as new mutations and are not inherited from a parent. However, autosomal dominant inheritance with transmission from parent to child has been reported in rare cases.^[1][2][3]

The CHD7 gene provides instructions for making a protein that most likely regulates gene activity (expression). Most mutations in the CHD7 gene lead to the production of an abnormally short, nonfunctional CHD7 protein, which is thought to disrupt the regulation of gene expression. Changes in gene expression during embryonic development likely cause the signs and symptoms of CHARGE syndrome.

About one-third of individuals with CHARGE syndrome do not have an identified mutation in the CHD7 gene. The cause is unknown in these individuals, but researchers suspect that other genetic and/or environmental factors may be involved.^[3]

CHARGE syndrome is usually not inherited, typically occurring due to a new (de novo) gene mutation in the affected individual. However, rare familial cases inherited in an autosomal dominant manner have been described.

To our knowledge, all individuals who have a CHD7 mutation have some features of CHARGE syndrome (i.e. penetrance is 100%). In rare instances, one parent may have mild features, and the family history may appear to be negative because of failure to recognize the mild features of the condition.

The risk to the siblings of an affected individual depends on the genetic status of the individual's parents. If a parent of an affected child also has CHARGE syndrome, the risk for each sibling to inherit the condition is 50%. If neither parent is affected, the risk to each sibling of an affected child is estimated to be 1%-2%, most likely attributable to germline mosaicism. Prenatal diagnosis for pregnancies at increased risk is possible if the disease-causing CHD7 mutation has been identified in an affected family member.^[1]

Genetic testing is available for CHARGE syndrome. The CHD7 gene is the only gene in which mutations are known to cause CHARGE syndrome. The CHD7 mutation detection rate when sequence analysis is performed is estimated to be 65%-70% for all typical and suspected cases combined.^[1]

GeneTests lists the names of laboratories that are performing clinical genetic testing for CHARGE syndrome. To view the contact information for these laboratories, click here. Please note that most of the laboratories listed through GeneTests do not accept direct contact from patients and their families. Therefore, if you are interested in learning more, you will need to work with a health care provider or a genetics professional.

To find a medical professional who specializes in genetics, you can ask your doctor for a referral or you can search for one yourself. Online directories are provided by the American College of Medical Genetics and the National Society of Genetic Counselors. If you need additional help, contact a GARD Information Specialist. You can also learn more about genetic consultations from Genetics Home Reference.