Involucrin, a component of the keratinocyte crosslinked envelope, is found in the cytoplasm and crosslinked to membrane proteins by transglutaminase. This gene is mapped to 1q21, among calpactin I light chain, trichohyalin, profillaggrin, loricrin, and calcyclin.

Green and Djian (1992) reviewed the alterations in the involucrin gene during evolution of primates from nonprimates. As reflected in the 17 species examined, the changes involved short tandem repeats. Evolution of the IVL gene took place through mechanisms that shortened the length of the repeats, increased their number, and changed their codon sequence. As part of this trend, one entire segment of repeats was replaced by another located elsewhere in the coding region.