Aims: Most patients (98%) with Friedreich's ataxia (FRDA) are homozygous for the GAA repeat expansion in FXN. Only a few compound heterozygous patients with an expanded repeat on one allele and a point mutation or an intragenic FXN deletion on the other allele are described. In a minority of the patients only a heterozygous pattern of the repeat expansion can be detected. Using array analysis after GAA repeat expansion testing, we identified a FRDA patient who is compound heterozygous for an expanded GAA repeat and a complete FXN deletion. Since not only repeat expansions and point mutations, but also large rearrangements can be the underlying cause of FRDA, a quantitative test should also be performed in case a patient shows only one allele with an expanded GAA repeat in FXN.

doi.org/10.1089/gtmb.2012.0012, hdl.handle.net/1765/57451
Genetic Testing and Molecular Biomarkers
Department of Clinical Genetics

van den Ouweland, A., Thornton, A., Bolman, G., Wouters, C., Becht-Noordermeer, C., Deelen, W., … Halley, D. (2012). Complete FXN deletion in a patient with Friedreich's ataxia. Genetic Testing and Molecular Biomarkers, 16(9), 1015–1018. doi:10.1089/gtmb.2012.0012