Lab test

Fragile X Carrier Testing - Carrier Screen

Fragile X carrier testing examines the FMR1 gene to measure the number of CGG repeats and determine carrier or affected status.

Typical price

From $399

Results

1-3 business days

Preparation

See preparation notes below

Sample

Blood draw or sample collection at a local center

Fragile X carrier testing examines the FMR1 gene to measure the number of CGG repeats and determine carrier or affected status. Fragile X syndrome is an inherited condition associated with intellectual and developmental differences. The test can also detect premutation carriers, who may have no symptoms but can pass an expanded repeat to a child. Clinicians order it for reproductive planning, family-risk assessment, and evaluation of certain symptoms.

• FMR1 gene CGG repeat expansion The number of CGG repeats is measured to identify premutation carriers, full mutations, and possible affected status.

• People with a family history of fragile X syndrome.
• Individuals with unexplained developmental or reproductive concerns.
• Couples considering reproductive carrier screening.
• Women with a history of certain reproductive conditions.
• Anyone with a partner known to be a fragile X carrier.

• No fasting is required for fragile X testing.
• Take usual medications unless told otherwise.
• Share family history and reproductive plans.
• A blood sample is commonly used.
• Genetic counseling is advised before and after testing.

The number of FMR1 CGG repeats determines whether a result falls in the normal, premutation, or full mutation range. A premutation can have reproductive implications, while a full mutation is associated with fragile X syndrome. Because repeat size can change when passed to a child, results are best reviewed with a genetic counselor. Discuss the findings with a healthcare provider and genetic counselor.

• Alabama
• Alaska
• Arizona
• Arkansas
• California
• Colorado
• Connecticut
• Delaware
• Florida
• Georgia