Probable C-mannosyltransferase that mediates C-mannosylation of tryptophan residues on target proteins. Brain, heart, placenta and testis. It has been suggested that DPY19L2P1 is an inactive pseudogene from which DPY19L2 has evolved by duplication. However, expressed transcript sequences derived from the DPY19L2P1 locus are known to exist. Belongs to the dpy-19 family.