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Gene name / Alternate gene name
  • AFF2
AF4/FMR2 family, member 2
Lab area
Genome Diagnostics - Molecular Genetics
Method and equipment
AFF2 5'UTR trinucleotide (CCG) repeat analysis via PCR
Expected turn-around time
Prenatal samples: 2 weeks Pregnancy/STAT: 2-3 weeks Routine: 4-6 weeks
Specimen type

Blood; gDNA.

For details about specimen requirements, please refer to: Specimen Type & Requirements (PDF).

Specimen requirements
  • Blood: 5-10 mL in EDTA, 0.5 mL in EDTA (neonate); 
  • DNA-minimum 10 ug in 100 uL low TE (pH8.0)
Storage and transportation

Room Temperature

For details about specimen requirements, please refer to: Specimen Type and Requirements

Special requirements

Special Instructions for Genome Diagnostics Samples

If sample shipment >48 hours, ship on ice. The eligibility for this test is determined by the presence of a family history suggestive of X-linked intellectual disability; a pedigree must be provided for Fragile X E testing.

Shipping information
The Hospital for Sick Children
Division of Genome Diagnostics
555 University Avenue, Black Wing, Room 3416
Toronto, ON
M5G 1X8
Phone: 416-813-7200 ext. 2
Hours: Monday to Friday, 8 a.m. to 4:30 p.m.
Off hours: Please send to Rapid Response Laboratory, 555 University Avenue, Room 3642
Email Molecular Lab:
Email Cytogenetics:
Background and clinical significance

FRAXE is a form of non-syndromic X-linked intellectual disability characterized by mild intellectual disability. The FRAXE phenotype is quite variable, and tends to include slow learning, hyperactivity, attention problems and language delay. The gene associated with FRAXE is called FMR2. The normal gene contains a three base pair sequence, which is repeated on each X chromosome (called a CCG repeat). The principal mutation causing FRAXE is an expansion of the CCG repeat sequence within the FMR-2 gene.

See related information sheet: FRAXE Molecular Analysis

Disease condition

Fragile X E Syndrome

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