The fragile X syndrome is the most common inherited cause of mental retardation, affecting approximately 1 in 4000-9000 males and 1 in 700015000 females. Fragile X syndrome is caused in most of cases by expansions of a (CGG) trinucleotide repeat in the 5’UTR of the FMR1 gene at FRAXA locus and subsequent abnormal methylation of neighbouring CpG island leading to the loss of the protein product FMRP.
Normal subjects have 2 to 50 copies of the repeat; pre-mutations in normal transmitting males and female carriers range from 50 to 200
copies, and affected subjects have more than 200 copies. The term “Fragile X syndrome” is commonly used to refer to the syndrome caused by CGG expansions in FMR1 gene. However, in a small number of families, another fragile site has been linked to expansions at the nearby FRAXE locus of the FMR2 gene which is 600 kb distal to FRAXA.
Normal subjects have 6 to 25 copies of this repeat, whereas subjects with more than 200 copies of the CCG repeat express the FRAXE site, and most of them suffer from mental impairment.
|#||Product||Cat. No.||Reaction size/kit|
|1||Fragile X FMR1 and FMR2 detection kit||DFX25||25|
|2||Fragile X FMR1 and FMR2 detection kit||DFX50||50|