Type and position of repeat interruptions as determinants of disease severity and expansion size in Friedreich ataxia

Type and position of repeat interruptions as determinants of disease severity and expansion size in Friedreich ataxia, Benkirane, Mehdi et al., Genetics in Medicine, Volume 0, Issue 0, 101588 DOI: 10.1016/j.gim.2025.101588  

Three groups of FRDA patients were identified by the simultaneous analysis of the precise distance (“depth”) between the interruptions (mostly non-triplet) and the 3’ end of the expansion (P < 0.001), the smaller expansion size (P < 0.001), and AAO (P < 0.001). Classical FRDA corresponds to absence of interruption or interruption depth 18 (AUC = 0.97; 95% CI, 0.92-1) and AAO >34 years. Multiple (>5) triplet interruptions hamper further expansion.

Type and position of repeat interruptions as determinants of disease severity and expansion size in Friedreich ataxia