Friedreich’s ataxia (FRDA) is the most common hereditary ataxia, with an estimated prevalence of 1 in 50000 and a deduced carrier frequency of 1 in 120 in Europe populations. FRDA is an autosomal recessive degenerative disease characterized by a progressive gait and limb ataxia, a lack of tendon reflexes in the legs, loss of position sense, dysarthria, and pyramidal weakness of the legs.
The most common DNA abnormality associated with Friedreich’s ataxia (FRDA) is the expansion of a GAA triplet repeat polymorphism localized in the first intron of the gene encoding frataxin (FXN). About 98% of individuals with FRDA are homozygous for this expansion.
Pathogenic GAA expansion alleles are in the size range of 50 to >1300 repeats with three different intervals, healthy (between 5-30 repeats), with mild symptoms (30-49 repeats) and with severe symptoms (50-1300 repeats) (see Table 1).
Adellgene® Friedreich’s Ataxia is a diagnostic kit which detects the number of repetitions of GAA in the first intron of the gene encoding frataxin (FXN). The technology is based on the polymerase chain reaction (PCR) amplification of genomic DNA, ex-tracted and purified from peripheral blood, followed by fluorescence analysis of the size of the PCR fragments obtained by a genetic analyzer and conversion of that size into the relevant number of GAA repeats