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Reviewed September 2015

What is the official name of the SMC1A gene?

The official name of this gene is “structural maintenance of chromosomes 1A.”

SMC1A is the gene's official symbol. The SMC1A gene is also known by other names, listed below.

Read more about gene names and symbols on the About page.

What is the normal function of the SMC1A gene?

The SMC1A 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 SMC1A gene (which is usually called the SMC1 protein) 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 SMC1 protein is part of a protein group called the cohesin complex that holds the sister chromatids together.

Researchers believe that the SMC1 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.

Does the SMC1A gene share characteristics with other genes?

The SMC1A gene 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 SMC1A gene related to health conditions?

Cornelia de Lange syndrome - caused by mutations in the SMC1A gene

More than 35 mutations in the SMC1A gene have been identified in people with Cornelia de Lange syndrome, a developmental disorder that affects many parts of the body. Researchers estimate that mutations in this gene account for about 5 percent of all cases of this condition.

Most of the SMC1A gene mutations that cause Cornelia de Lange syndrome change single protein building blocks (amino acids) in the SMC1 protein. These mutations alter 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 SMC1A 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, SMC1A gene mutations often cause less significant delays in development and growth and are less likely to cause major birth defects.

Where is the SMC1A gene located?

Cytogenetic Location: Xp11.22-p11.21

Molecular Location on the X chromosome: base pairs 53,374,149 to 53,422,728

The SMC1A gene is located on the short (p) arm of the X chromosome between positions 11.22 and 11.21.

The SMC1A gene is located on the short (p) arm of the X chromosome between positions 11.22 and 11.21.

More precisely, the SMC1A gene is located from base pair 53,374,149 to base pair 53,422,728 on the X chromosome.

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

Where can I find additional information about SMC1A?

You and your healthcare professional may find the following resources about SMC1A 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 SMC1A gene or gene products?

  • DXS423E
  • KIAA0178
  • segregation of mitotic chromosomes 1
  • SMC1
  • SMC1-alpha
  • SMC1L1
  • SMCB

Where can I find general information about genes?

The Handbook provides basic information about genetics in clear language.

These links provide additional genetics resources that may be useful.

What glossary definitions help with understanding SMC1A?

acids ; cell ; cell division ; chromatid ; chromosome ; cohesion ; DNA ; gene ; gene regulation ; nucleus ; protein ; segregation ; sister chromatid ; sister chromatid cohesion ; syndrome ; X-inactivation

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

See also Understanding Medical Terminology.

References (10 links)


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