Table 1.
Classification of human mucins: Length of the tandemly repeated amino acid sequence (TR), location of protein expression and chromosomal localization
| MUC protein | Amino acids in TR | Main location of expression | Chromosome locus | References |
| Secreted: | ||||
| MUC2 | 23/16 | small intestine, colon, tracheobronchial tissue | 11p15.5 | 128–131 |
| MUC5AC | 8/5 | stomach, respiratory tissue, Brunner's glands | 11p15.5 | 128, 132–135 |
| MUC5B | 29 | salivary glands, tracheobronchial tissue, Brunner's glands, endocervix, gall bladder, pancreas | 11p15.5 | 21, 70, 128, 136, 137 |
| MUC6 | 169 | stomach, gall bladder, Brunner's glands | 11p15.5 | 70, 128, 138, 139 |
| MUC7 | 23 | salivary glands | 4q13.3 | 140–142 |
| MUC8 | 13/41 | tracheobronchial tissue | 12q24.3 | 143, 144 |
| MUC19 (predicted protein) | 7/7/15/16/9/8/5 | salivary glands, tracheobronchial tissue | 12q12 | 145 |
| Membrane-bound: | ||||
| MUC1 | 20 | all epithelia | 1q22 | 146–148 |
| MUC3A | 17/375 | small intestine, colon, gall bladder | 7q22 | 129, 149–151 |
| MUC3B | 17/375 | small intestine, colon | 7q22.1 | 149–151 |
| MUC4 | 16 | virtually all epithelia | 3q29 | 152, 153 |
| MUC12 | 28 | colon | 7q22.1 | 154 |
| MUC13 | 15 | trachea, small intestine, colon | 3q21.2 | 155 |
| MUC15 | none | spleen, small intestine, colon, prostate, lung | 11p14.2 | 156 |
| MUC16 | 156 | ovarian tissue, ocular tissue | 19p13.2 | 157–159 |
| MUC17 | 59 | pancreas, small intestine, colon | 7q22.1 | 20, 35, 160 |
| MUC20 | 19 | renal tissue | 3q29 | 161 |