Deletions of the short arm of chromosome 18 were first reported 1963. In the years since, multiple papers have described patients with 18p- and a diagnosis of dystonia. Dystonia is a neurologic condition. It causes muscle spasms that can lead to cramping or abnormal posture and movements and can occur at any time during one's lifetime

Although we've known about the link between 18p- and dystonia for decades, we have not known which patients with 18p- were at risk to have this dystonia. In a paper published in 2013, researchers described several individuals with dystonia that have a mutation in a gene on chromosome 18p. This gene is called GNAL. It is located at 11.7 Mb within chromosome band 18p11.21.

What does this mean for people with 18p-? Individuals with deletions that include this gene may be at an increased risk to develop dystonia. People with deletions of the entire p arm have deletions that include GNAL. About 2/3 of individuals with partial 18p deletions are missing this gene. This means that 2/3 of people with non-centromeric breakpoints are at risk for developing dystonia.

However, it is important to note that not everyone who is missing this gene will develop dystonia. Rather, it appears that a deletion of this gene increases the risk for dystonia. At this point in time, we do not know what percentage of people with deletions of GNAL will develop dystonia. It appears to be a small minority, as only 3% of study participants that are missing this gene have been diagnosed with dystonia.

If you are concerned about the possibility of dystonia, we recommend speaking with a physician. A neurologic evaluation may be recommended to confirm the diagnosis. Treatment options may include medication, injections, or physical therapy. We also encourage families with 18p- to consider enrolling in the research study. With their help, we will learn more about the relationship between 18p- and dystonia.