As a consequence, the FA core complex (comprising the majority of proteins in the FA group) mono-ubiquitinates the FANCI-FANCD2 dimeric complex, which primes ubiquitinated FANCD2, together with other proteins, to perform the “unhooking” step in the resolution of the ICL in which a DSB is created on the DNA strand opposite the strand harboring the cross-linked nucleotide. This evidence concerns the gene FANCD2 and Friedreich ataxia.