FXS DTekt™ v1.2

Fragile X Syndrome is the most common inherited cause of intellectual disability. The prevalence of this condition is 1 in 4000 male births and 1 in 5000 to 8000 female births. All affected males and approximately half of carrier females exhibit mild to severe symptoms of the disease, including intellectual disability, language and/or behavioral learning problems.

In over 98% of cases of Fragile X Syndrome, an unstable expansion of the CGG repeat is observed in the untranslated region of the FMR1 gene. The spectrum of the disease is as follows:

Normal: In these individuals, the likelihood of a change in the number of CGG repeats inherited from one generation to the next is very minimal.

Intermediate: In this condition, the number of repeats may increase from one generation to the next depending on which parent it is inherited from.

Premutation: A milder form of the disease is observed. Evidence has shown that when the defective gene is passed from the mother to the child, there is a possibility of an increase in the number of CGG repeats, but this condition is not observed in inheritance from the father.

Full mutation: An increase in this repeat from 200 and above plays a role in the severity of the disease. The precise estimation of disease symptoms is not straightforward and depends on the number of repeats and gene methylation. In this case, the gene is silenced, and mRNA is not produced, thus no product is expressed.

Mosaicism: An affected individual may exhibit more than one repeat state, known as mosaicism. In this case, the likelihood of observing two or more increased repeats is identified in the individual’s blood test results.

The KBC FXS Dtekt™ v1.2 Kit is based on the PCR method, used for rapid diagnosis of affected, carrier, and healthy individuals with regard to Fragile X Syndrome. The triplet CGG repeats of the FMR1 gene located on the X chromosome are amplified by PCR and the final result is visualized using 1.5% agarose gel and the capability to determine the number of repeats is present using capillary electrophoresis.