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


Reviewed September 2015

What is the official name of the SMC3 gene?

The official name of this gene is “structural maintenance of chromosomes 3.”

SMC3 is the gene's official symbol. The SMC3 gene is also known by other names, listed below.

What is the normal function of the SMC3 gene?

The SMC3 gene provides instructions for making a protein that is part of the structural maintenance of chromosomes (SMC) family. Within the nucleus, SMC proteins help regulate the structure and organization of chromosomes.

The protein produced from the SMC3 gene helps control chromosomes during cell division. Before cells divide, they must copy all of their chromosomes. The copied DNA from each chromosome is arranged into two identical structures, called sister chromatids, which are attached to one another during the early stages of cell division. The SMC3 protein is part of a protein group called the cohesin complex that holds the sister chromatids together.

Researchers believe that the SMC3 protein, as a structural component of the cohesin complex, also plays important roles in stabilizing cells' genetic information, repairing damaged DNA, and regulating the activity of certain genes that are essential for normal development.

Although the SMC3 protein is found primarily in the nucleus, some of this protein is transported out of cells. The exported protein, which is usually called bamacan, may be involved in sticking cells together (cell adhesion) and cell growth. Bamacan is a component of basement membranes, which are thin, sheet-like structures that separate and support cells in many tissues. Little else is known about the function of this protein outside the cell, but it appears to be important for normal development.

Does the SMC3 gene share characteristics with other genes?

The SMC3 gene belongs to a family of genes called proteoglycans (proteoglycans). It also belongs to a family of genes called SMC (structural maintenance of chromosomes proteins).

A gene family is a group of genes that share important characteristics. Classifying individual genes into families helps researchers describe how genes are related to each other. For more information, see What are gene families? ( in the Handbook.

How are changes in the SMC3 gene related to health conditions?

Cornelia de Lange syndrome - caused by mutations in the SMC3 gene

At least 15 mutations in the SMC3 gene have been found to cause Cornelia de Lange syndrome, a developmental disorder that affects many parts of the body. Researchers estimate that mutations in this gene account for 1 to 2 percent of all cases of this condition.

Most of the SMC3 gene mutations that cause Cornelia de Lange syndrome either change single protein building blocks (amino acids) in the SMC3 protein or add or delete a small number of amino acids in the protein. Each of these mutations alters the structure and function of the protein, which likely interferes with the activity of the cohesin complex and impairs its ability to regulate genes that are critical for normal development. Although researchers do not fully understand how these changes cause Cornelia de Lange syndrome, they suspect that altered gene regulation probably underlies many of the developmental problems characteristic of the condition.

Studies suggest that mutations in the SMC3 gene tend to cause a form of Cornelia de Lange syndrome with relatively mild features. Compared to mutations in the NIPBL gene, which are the most common known cause of the disorder, SMC3 gene mutations often cause less significant delays in development and growth and are less likely to cause major birth defects.

Where is the SMC3 gene located?

Cytogenetic Location: 10q25

Molecular Location on chromosome 10: base pairs 110,567,691 to 110,604,634

The SMC3 gene is located on the long (q) arm of chromosome 10 at position 25.

The SMC3 gene is located on the long (q) arm of chromosome 10 at position 25.

More precisely, the SMC3 gene is located from base pair 110,567,691 to base pair 110,604,634 on chromosome 10.

See How do geneticists indicate the location of a gene? ( in the Handbook.

Where can I find additional information about SMC3?

You and your healthcare professional may find the following resources about SMC3 helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the SMC3 gene or gene products?

  • BAM
  • bamacan
  • basement membrane-associated chondroitin proteoglycan
  • BMH
  • chondroitin sulfate proteoglycan 6
  • chromosome-associated polypeptide
  • CSPG6
  • HCAP
  • SMC3L1

See How are genetic conditions and genes named? ( in the Handbook.

What glossary definitions help with understanding SMC3?

acids ; basement membrane ; basement membranes ; cell ; cell adhesion ; cell division ; chromatid ; chromosome ; cohesion ; DNA ; gene ; gene regulation ; nucleus ; protein ; proteoglycan ; sister chromatid ; sister chromatid cohesion ; sulfate ; syndrome

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


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  • NCBI Gene (
  • Revenkova E, Focarelli ML, Susani L, Paulis M, Bassi MT, Mannini L, Frattini A, Delia D, Krantz I, Vezzoni P, Jessberger R, Musio A. Cornelia de Lange syndrome mutations in SMC1A or SMC3 affect binding to DNA. Hum Mol Genet. 2009 Feb 1;18(3):418-27. doi: 10.1093/hmg/ddn369. Epub 2008 Nov 7. (


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: September 2015
Published: November 23, 2015