CHARGE SYNDROME

CHD7 Sequencing

DNA ANALYSIS

CHARGE syndrome is combination of associated congenital anomalies including Coloboma of the eye, various Heart anomalies, Choanal Atresia or cleft lip and/or palate, mental and/or growth Retardation, hypogonadotropic hypogonadism with Genitourinary anomalies, and characteristic external Ear malformations that can lead to hearing loss. A clinical diagnosis of CHARGE syndrome can be made with the presence of 3 major characteristics or 2 major and 3 minor characteristics. The incidence of CHARGE syndrome may be as high as 1 in 8,500 live births, and although most mutations in affected individuals are new mutations, this syndrome can be inherited in an autosomal dominant fashion. Mutations in both coding exons and conserved splice sites of the chromodomain helicase DNA-binding protein 7gene (CHD7; OMIM #608892) have been linked with CHARGE syndrome. CHD7 is thought to be involved in embryonic development and cell-cycle regulation. Sequence analysis of the coding region of the CHD7 gene is available on a clinical basis at the Medical Genetics Laboratories at Baylor College of Medicine.

Reasons For Referral:

Confirmation of clinical diagnosis of CHARGE syndrome.
Prenatal diagnosis (known mutation only).

Testing Methodology:

Full Sequencing: PCR amplification of 38 exons contained in the CHD7 gene coding region will performed on patient genomic DNA. Direct sequencing of amplification products is performed in both the forward and reverse directions using automated fluorescence dideoxy sequencing methods.

Specimen Requirements:

Blood for DNA: EDTA (purple-top) tubes: Adult/Child: Minimum 6-14 cc
Requisition form must accompany the specimen. Prior to any genetic testing, we recommend genetic counseling and we request that the subject sign our consent statement and submit it with the sample. To receive forms, additional information or specimen collection kits, please contact the laboratory. Please call laboratory for specific requirements for prenatal testing.

Turnaround Time:

Index: 21 days
Known Familial Mutation: 3 weeks

CPT Codes and Prices:

Index: 83904X76, 83912, 83909x76, 83898x38, 83894, 83891
Known Familial Mutation: 83904x2, 83912, 83909x2, 83898, 83891, 83894

Shipping Information

Forms:

>> Gene Sequencing Requisition
>> Prenatal Requisition

References:

Lalani SR, Safiullah AM, Fernbach SD, Harutyunyan KG, Thaller C, Peterson LE, McPherson JD, Gibbs RA, White LD, Hefner M, Davenport SLH, Graham JM, Bacino CA, Glass NL, Towbin JA, Craigen WJ, Neish SR, Lin AE, Belmont JW. (2005) Spectrum of CHD7 mutations in 110 individuals with CHARGE syndrome and genotype-phenotype correlation. Am. J. Hum. Genet. 78: 303-314.

Test Codes:

Index: 6165
Known Familial Mutation: 6170
Prenatal (Known Familial Mutation Only): 6175