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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®

MUC gene family

Reviewed June 2013

What are the MUC genes?

Genes in this gene family provide instructions for making proteins called mucins. These proteins make up mucus, a slippery substance that lubricates and protects the lining of the airways, digestive system, reproductive system, and other organs and tissues.

Some mucins, called secreted mucins, are released from cells to become part of the mucus barrier. Other mucins, called membrane-associated mucins, span the cell's outer membrane. Both secreted and membrane-associated mucins contain a region called the mucin domain that is composed of repeated stretches of protein building blocks (amino acids). Sugar molecules are attached to certain amino acids in this region. Mucins are extensively modified by the addition of numerous chains of sugar molecules, which are critical for the function of the proteins. The network of sugar molecules that project from the proteins like branches on a tree, prevents access to the cell surface below, protecting the body from foreign invaders and other particles. The sugars also attract water molecules, helping lubricate and hydrate the tissues.

In addition to protecting the body, membrane-associated mucins are involved in cell signaling. The portion of the protein that reaches inside the cell, called the cytoplasmic tail, relays signals from outside the cell to the cell's nucleus; these signals instruct the cell to undergo certain changes. Through this process, mucins are thought to be involved in cell growth and division (proliferation), helping cells stick to one another (cell adhesion), cell movement (motility), and cell survival. Some researchers suggest that certain membrane-associated mucins are able to help control the activity of other genes, and some mucins appear to be involved in development of organs before birth.

Which genes are included in the MUC gene family?

The HUGO Gene Nomenclature Committee (HGNC) provides an index of gene families ( and their member genes.

Genetics Home Reference summarizes the normal function and health implications of this member of the MUC gene family: MUC1.

What conditions are related to genes in the MUC gene family?

Genetics Home Reference includes these conditions related to genes in the MUC gene family:

  • medullary cystic kidney disease type 1

Where can I find additional information about the MUC gene family?

You may find the following resources about the MUC gene family helpful.

  • Immunobiology: The Immune System in Health and Disease (fifth edition, 2001): The Epithelial Surfaces of the Body Are the First Defenses Against Infection (

What glossary definitions help with understanding the MUC gene family?

acids ; cell ; cell adhesion ; digestive ; digestive system ; domain ; epithelial ; gene ; glycosylation ; mucus ; nucleus ; proliferation ; protein

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.


These sources were used to develop the Genetics Home Reference summary for the MUC gene family.

  • Thornton DJ, Rousseau K, McGuckin MA. Structure and function of the polymeric mucins in airways mucus. Annu Rev Physiol. 2008;70:459-86. Review. (
  • Hattrup CL, Gendler SJ. Structure and function of the cell surface (tethered) mucins. Annu Rev Physiol. 2008;70:431-57. Review. (
  • Linden SK, Sutton P, Karlsson NG, Korolik V, McGuckin MA. Mucins in the mucosal barrier to infection. Mucosal Immunol. 2008 May;1(3):183-97. doi: 10.1038/mi.2008.5. Epub 2008 Mar 5. Review. (


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? ( in the Handbook.

Reviewed: June 2013
Published: February 8, 2016