To determine whether MSH2 underlies aberrant responses in other BRCA-FA cells, we tested whether MSH2 contributed to MMC sensitivity in cells lacking BRCA-FA proteins known to interact with MMR proteins, such as BRCA1 or the central FA pathway protein, FANCD2 (Wang et al, 2000; Williams et al, 2011). The gene discussed is BRCA1; the disease is Friedreich ataxia.