This gene encodes a small salivary mucin, which is thought to play a role in facilitating the clearance of bacteria in the oral cavity and to aid in mastication, speech, and swallowing. The central domain of this glycoprotein contains tandem repeats, each composed of 23 amino acids. This antimicrobial protein has antibacterial and antifungal activity. The most common allele contains 6 repeats, and some alleles may be associated with susceptibility to asthma. Alternatively spliced transcript variants with different 5' UTR, but encoding the same protein, have been found for this gene.