XRCC2 and Friedreich ataxia: Moreover, since biallelic mutations in other critical HR factors, such as BRCA2/FANCD1, PALB2/FANCN, RAD51/FANCR, RAD51C/FANCO and XRCC2/FANCU have been identified as an underlying cause of an FA-like phenotype in other patients, this highlights the importance of the HR pathway in dealing with impediments to DNA replication during embryonal development caused by naturally occurring DNA inter-/intra-strand and DNA/protein-cross-links [191–196].