Fanconi anaemia (FA) is an autosomal recessive disease featuring diverse clinical symptoms in addition to chromosomal instability and hypersensitivity to crosslinking agents. The much increased risk of FA patients developing leukaemia and squamous cell carcinomas makes FA an important model disease for cancer predisposition. Studies documenting the characteristics of FA cells and their response to environmental toxins have failed thus far to disclose the basic cellular process that is primarily disturbed in FA cells. Complementation analysis suggests that mutations in at least four different genes can cause FA (complementation groups FA-A to FA-D). The cDNA for FA-C has been cloned and found to encode a novel protein that localises to the cytoplasmic compartment of cells. Even though the protein's function is still unknown at present, research has now reached the point from where rapid progress to a detailed understanding of this syndrome may be foreseen.