• Test Code:
    1482
  • Department:
    Molecular Genetics
  • Test Synonyms:
    FMR1-Related Disorders FMR1
  • CPT Code(s):
    8142381244 (if expansion is found)
Background:

FMR1-related primary ovarian insufficiency (POI) occurs in 20-25% of female FMR1 premutation carriers.  POI is caused by a premutation, >54 trinucleotide (CGG) repeats, in the FMR1 gene.  The hallmark clinical feature is cessation of menses before age 40 years.  Genetic counseling is recommended.

Reason for Referral
Testing is indicated for females with clinical features of early menopause, particularly those with a family history of Fragile X syndrome.

Methodology:

PCR and capillary electrophoresis  analysis is used to measure the number of CGG trinucleotide repeats in the 5’ untranslated region of the FMR1 gene at Xq27.3; additionally, CGG repeat size and methylation status is determined by Southern blot for large premutations (>CGG150) and for fully expanded alleles.

Allele Types #CGG Repeats:

  • Normal: 5 - 44
  • Intermediate: 45 - 54
  • Premutation: 55 – 200
  • Full mutation (i.e. disease-causing): >200

Specimen Requirements:

Blood: EDTA (purple-top) tube or ACD (yellow-top) tube

    • Adult: 6mL
    • Child: 3mL

DNA: 20ng at a minimum of 100ng/µL

A REQUISTION FORM MUST ACCOMPANY ALL SAMPLES. Please include detailed clinical information, including ethnicity, clinical history, and family history.

 

Test Performed (Days):

Weekly

Turn Around Time:

7-10 days

Shipment Sensitivity Requirements:

  • Keep specimen cold during transit, but do not ship on dry ice. 
  • Contact Client Services at (855) 535-1522 for shipping kits and instructions. 
  • Please use the cold pack provided in the KDL shipping kit. 
  • Ship the specimen overnight express, using the FedEx priority overnight label provided. 

References:

NCBI GeneReviews: FMR1-Related Disorders by Robert A. Saul and Jack C. Tarleton (2012) http://www.ncbi.nlm.nih.gov/books/NBK1384/

Additional Info:

Related tests in our laboratory: 
    Fragile X syndrome
    Fragile X-associated Tremor Ataxia syndrome (FXTAS)

Prior to any genetic testing we recommend genetic counseling. To receive forms and information about prenatal diagnostic testing, please contact Client Services at (855) 535-1522.