Dapper2 is a 774 amino acid protein that exists as multiple alternatively spliced isoforms and is a mammalian homolog of the Xenopus laevis protein dapper. Containing a C-terminal PDZ-binding motif, Dapper2 is thought to promote the lysosomal degradation of nodal receptors, possibly functioning to negatively regulate the nodal signaling pathway. The gene encoding Dapper2 maps to human chromosome 6, which contains 170 million base pairs and comprises nearly 6% of the human genome. Deletion of a portion of the q arm of chromosome 6 is associated with early onset intestinal cancer, suggesting the presence of a cancer susceptibility locus. Additionally, Porphyria cutanea tarda, Parkinson's disease, Stickler syndrome and a susceptibility to bipolar disorder are all associated with genes that map to chromosome 6.