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Choroideremia
CHM (Choroideremia)
Choroideremia (CHM) is an X-linked recessive condition characterized by progressive degeneration of the photoreceptors, retinal pigment epithelium and choriocapillaris. Symptoms become evident by the 2nd and 3rd decades of life leading to tunnel vision and often blindness. Female carriers exhibit a milder phenotype than affected males marked by the presence of patchy areas of atrophy of the retinal pigment epithelium, but show no serious visual impairment. Mutations in the CHM gene have been found in approximately 74-95% of males with choroideremia. Most commonly, nonsense mutations and small deletions/insertions are found in the CHM gene. Less frequent are splice site mutations and gene rearrangements, including gross deletions of one or more exons.
Using genomic DNA obtained from blood (1-5 mL in EDTA) or buccal brushes, bi-directional sequence analysis of the entire coding region of the CHM gene is performed. This approach is expected to identify >99% of existing small, intragenic mutations. When indicated, CopyDx quantitative PCR (qPCR) analysis is available for detection of a partial or whole gene deletion. Mutation-specific testing in family members and prenatal diagnosis in at-risk pregnancies is available once a mutation in an affected person has been defined.
Information Sheet, including prices and CPT codes
Consent Document
Genetic Test Sample Submission Form (Test Requisition Form) including Payment Options
Choroideremia; Progressive Tapetochoroidal dystrophy; CHM; REP-1; photoreceptors; retinal pigment epithelium; choriocapillaris; night blindness; peripheral vision; tunnel vision; blindness; progressive degeneration; X-linked recessive
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