- Patient Preparation
- For buccal collection, the patient should not eat, drink, smoke, or chew gum for 30 minutes before collecting oral samples.
- Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B). Or, one buccal sponge using the ORAcollect™collection kit (ARUP supply #49295)
- Specimen Preparation
- Transport 3 mL whole blood. (Min: 3 mL); or, one buccal sponge in the ORAcollect™collection kit.
- Storage/Transport Temperature
- For whole blood, ship refrigerated. For buccal sponge, ship at room temperature.
- Unacceptable Conditions
- Use only the ORAcollect™kit for buccal sampling. Other buccal collection devices (e.g., swab) are not acceptable for testing.
- Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable
|Test Number||Components||Reference Interval|
|Fragile X (FMR1) Mutation Screen||By report|
|0040011||Fragile X (FMR1) Diagnostic (INACTIVE as of 01/06/14. Refer to 2009033)||By report|
Characteristics: Fragile X syndrome, the most common heritable form of mental retardation, is characterized by moderate mental retardation in males and mild mental retardation in females, behavioral phenotype, connective tissue anomalies, and physical findings. Older male premutation carriers may develop fragile X-associated tremor/ataxia syndrome (FXTAS) characterized by progressive cerebellar ataxia and intention tremor. Female premutation carriers may develop premature ovarian insufficiency (20 percent), or rarely, FXTAS.
Incidence of Disease: 1 in 4000 males and 1 in 8000 females.
Incidence of Premutation: 1 in 1000 males and 1 in 350 females.
Inheritance: X-linked dominant.
Penetrance: Reduced in females.
Cause: CGG expansions in the 5' untranslated region of FMR1 leading to hypermethylation of the gene and inhibition of FMR1 transcription.
Full mutation:>200 CGG repeats (methylated)
Premutation: 55-200 CGG repeats (unmethylated)
Intermediate: 45-54 CGG repeats (unmethylated)
Common: 5-44 CGG repeats (unmethylated)
Clinical Sensitivity & Specificity: 99 percent for pre and full mutation alleles.
Methodology: PCR followed by capillary electrophoresis.
Analytic Sensitivity & Specificity: 99 percent.
Limitations: Rare FMR1 mutations, unrelated to trinucleotide expansion may not be detected. Precise sizing of the CGG repeats is not provided. Intermediate alleles will not be reported. Diagnostic errors can occur due to rare sequence variations.
If reflexed, add 81244
|Component Test Code*||Component Chart Name||LOINC|
|2001947||Fragile X Screen, Specimen||31208-2|
|2001948||Fragile X Screen, Symptoms||56831-1|
|2001949||Fragile X Screen, Family History||10157-6|
|2001950||Fragile X Screen Interpretation||36913-2|
- FMR1 screen
- Fragile X tremor ataxia syndrome
- Inherited Mental Retardation
- Martin-Bell Syndrome