Is there an evolutionary relationship between WARP (von Willebrand factor A‐domain‐related protein) and the FACIT and FACIT‐like collagens?

We suggest that there is an evolutionary relationship between von Willebrand factor A-domain-related protein (WARP), and the fibril-associated collagen with interrupted triple helix (FACIT) and FACIT-like subfamilies of collagens. Data from a comparison of amino acid sequences, domain organisation and chromosomal location are consistent with the hypothesis that WARP and these collagens share a common collagen ancestor. In support of this is the observation that the WARP 3' coding region is GC-rich suggesting that this may represent the remnant of a triple helix protein domain which WARP has 'lost' during evolution.