This family represents the non-tandem repeat domain including cleavage site, the transmembrane helix domain, and the cytoplasmic tail of epiglycanin and related mucins [1].

1: Identification and expression of human epiglycanin/MUC21: a novel transmembrane mucin. Itoh Y, Kamata-Sakurai M, Denda-Nagai K, Nagai S, Tsuiji M, Ishii-Schrade K, Okada K, Goto A, Fukayama M, Irimura T; Glycobiology. 2008;18:74-83. PMID:17977904