May function in a protective capacity by promoting the clearance of bacteria in the oral cavity and aiding in mastication, speech, and swallowing. Binds P.aeruginosa pili. Monomer. Expressed in salivary gland tissues and only in those that contain mucous acinar cells (e.g. sublingual and submandibular glands) and not in salivary glands containing only serous acinar cells (e.g. parotid gland). N- and O-glycosylated. Contains fucose, mannose, galactose, N-acetylglucosamine and N-acetylgalactosamine. The most common allele, MUC7*6, contains a tandem repeat domain comprising 6 repeats (shown here) each composed of 23 amino acids. These repeats are very similar but not identical. In a large cohort of 375 individuals from a variety of ethnic backgrounds, three different alleles were detected, MUC7*6 being the most common, in all populations studied, followed by MUC7*5 (5 repeats), with frequency varying from 0.05 in Africans to 0.22 in East Asians. The MUC7*5 allele is less prevalent in patients with asthma than in controls, and seems to have a protective role in respiratory function. MUC7*8 (8 repeats), a novel rare allele, was identified in 1 Northern European individual. Disease susceptibility is associated with variants affecting the gene represented in this entry.