RAD51 and Friedreich ataxia: FA is caused by either inheriting biallelic germline loss-of-function mutations in one of the 22 genes (FANCA/C/D1/D2/E/F/G/I/J/L/M/N/O/P/Q/S/T/U/V/W) in the FA pathway or a monoallelic loss-of-function of RAD51 [1].