Fragile X Syndrome, PCR With Reflex to Southern Blot

CPT: 81243
Print Share

Test Details

Synonyms

  • FRAXA

Use

Carrier screening for individuals who are pregnant or considering pregnancy and who have no family or personal history of fragile X syndrome, fragile X-related disorders (primary ovarian insufficiency, or late-onset ataxia) or unexplained intellectual disabilities, developmental delay, or autism.

Methodology

Polymerase chain reaction (PCR) followed by capillary electrophoresis with reflex to Southern blot analysis for all positive samples

Additional Information

Fragile X syndrome is the leading cause of inherited intellectual disability, affecting approximately 1 in 4,000 males and 1 in 8,000 females. It is found in all ethnic groups, and can occur in families with no history of intellectual disability. Women may decide to have testing to find out if they are carriers, and therefore are at risk of having a child with fragile X syndrome. The carrier frequency in women is approximately 1 in 260. Fragile X test is commonly used for individuals at higher risk, including those that may be symptomatic or have a family history suggestive of fragile X syndrome.

Specimen Requirements

Specimen

Whole blood

Volume

10 mL

Container

Lavender-top (EDTA) tube or yellow-top (ACD) tube

Storage Instructions

Room temperature

Causes for Rejection

Frozen specimen; hemolysis; quantity not sufficient for analysis; improper container; unlabeled or mislabeled specimen

Clinical Information

References

American College of Obstetricians and Gynecologists Committee on Genetics. Committee Opinion No. 469: Carrier screening for fragile X syndrome. Obstet Gynecol. 2010;116(4):1008-10.20859177
Hagerman PJ, Hagerman RJ. The fragile X premutation: A maturing perspective. Am J Hum Genet. 2004 May;74(5):805-816.15052536
Jacquemont S, Hagerman RJ, Leehey MA, et al. Penetrance of the fragile X-associated tremor/ataxia syndrome in a premutation carrier population. JAMA. 2004 Jan 28; 291(4):460-469.14747503

For Providers

Please login to order a test.

 

© 2018  Laboratory Corporation of America® Holdings and Lexi-Comp Inc. All Rights Reserved.

CPT Statement/Profile Statement

The LOINC® codes are copyright © 1994-2018, Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee. Permission is granted in perpetuity, without payment of license fees or royalties, to use, copy, or distribute the LOINC® codes for any commercial or non-commercial purpose, subject to the terms under the license agreement found at https://loinc.org/license/. Additional information regarding LOINC® codes can be found at LOINC.org, including the LOINC Manual, which can be downloaded at LOINC.org/downloads/files/LOINCManual.pdf