Test for Fragile-X
The test for Fragile X is an analysis to determine if a person is affected by or a carrier of Martin-Bell syndrome, also known as Fragile X syndrome, the most common form of intellectual disability after Down syndrome, affecting approximately 1 in 1250 males and 1 in 2000 females.
It is a hereditary disease caused by an alteration of a gene located on the X chromosome. The name "Fragile X" comes from the fact that these alterations cause changes in the structure of the chromosome, which, under a microscope, shows a constriction at a specific point (where the gene is located).
Fragile X affects males much more frequently than females, as females have two copies of the X chromosome. The mental development of people affected by Fragile X varies greatly: some show almost normal cognitive abilities, others have mild intellectual disability, and still others experience more severe intellectual disability.
FRAGILE-X
Available panels
Fragile-X FRAXA
Fragile-X FRAXE
Fragile-X FRAXA/FRAXE
FMR1 (FRAXA) Long-range PCR: second-level test
FRAGILE-X
Who it's recommended for
The test for Fragile X is recommended in the case of:
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Developmental delay
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Family history of Fragile X
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Recurrent miscarriages
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Fertility issues
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Pre-conception
FRAGILE-X
Analysis method
The analysis is conducted by performing an enzymatic reaction for DNA amplification, known as Polymerase Chain Reaction (PCR), which allows for the in vitro amplification of a specific region of the molecule, copying it in several successive stages until millions of copies are obtained.
Using this method, the regions of the analyzed genes (FMR-1 and/or FMR-2, which contain the fragile sites FRAXA and FRAXE, respectively) are amplified.
The determination of the number of nucleotide triplet repeats (genotyping) is performed using electrophoresis in an automated genetic analyzer.