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Reviewed August 2014
What is the official name of the SMCHD1 gene?
The official name of this gene is “structural maintenance of chromosomes flexible hinge domain containing 1.”
SMCHD1 is the gene's official symbol. The SMCHD1 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 SMCHD1 gene?
The SMCHD1 gene provides instructions for making a protein that is involved in regulating gene activity by altering the structure of DNA. Specifically, the SMCHD1 protein plays a role in DNA methylation, which is the addition of methyl groups (consisting of one carbon atom and three hydrogen atoms) to DNA molecules. The addition of methyl groups turns off (silences) genes, so hypermethylated regions of DNA tend to have fewer genes that are turned on (active).
The SMCHD1 protein is involved in a process called X-inactivation or Lyonization. Early in embryonic development in females, one of the two X chromosomes is randomly and permanently inactivated in cells other than egg cells. X-inactivation ensures that females, like males, have only one active copy of the X chromosome in each body cell. The SMCHD1 protein helps to inactivate the X chromosome by hypermethylating certain areas of DNA called CpG islands. The protein then remains attached (bound) to the inactive X chromosome to help keep it inactivated throughout life.
The SMCHD1 protein also plays a role in hypermethylation of a region near the end of chromosome 4 called D4Z4. This region consists of 11 to more than 100 repeated segments, each of which is about 3,300 DNA base pairs (3.3 kb) long. The segment closest to the end of chromosome 4 contains a gene called DUX4. Because the D4Z4 region is hypermethylated, the DUX4 gene is silenced in most adult cells and tissues. Little is known about the function of the protein produced from the DUX4 gene; it appears to help control the activity of other genes.
Studies suggest that the SMCHD1 gene is also involved in repairing damaged DNA. However, little is known about its role in this process.
How are changes in the SMCHD1 gene related to health conditions?
Where is the SMCHD1 gene located?
Cytogenetic Location: 18p11.32
Molecular Location on chromosome 18: base pairs 2,655,887 to 2,805,017
(Homo sapiens Annotation Release 107, GRCh38.p2) (
The SMCHD1 gene is located on the short (p) arm of chromosome 18 at position 11.32.
More precisely, the SMCHD1 gene is located from base pair 2,655,887 to base pair 2,805,017 on chromosome 18.
See How do geneticists indicate the location of a gene? in the Handbook.
Where can I find additional information about SMCHD1?
You and your healthcare professional may find the following resources about SMCHD1 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 SMCHD1 gene or gene products?
See How are genetic conditions and genes named? in the Handbook.
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 SMCHD1?
atom ; atrophy ; cell ; chromatin ; chromosome ; CpG islands ; DNA ; DNA base ; domain ; egg ; embryonic ; epigenetic ; gene ; kb ; lyonization ; methyl ; methylation ; muscle cells ; muscular dystrophy ; mutation ; protein ; wasting ; X-inactivation
You may find definitions for these and many other terms in the Genetics Home Reference Glossary.
See also Understanding Medical Terminology.
References (8 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.