FANCL and Fanconi anemia: Ube2W has been shown to be responsible for the mono-ubiquitylation of BRCA1 (breast cancer early-onset 1) [22], Fanconi's anaemia proteins FANCL (Fanconi's anaemia, complementation group L) and FANCD2 (Fanconi's anaemia, complementation group D2) [23,24] and CHIP [15,16].