Genes of Interest on Proximal 18q

At this point, we only know of a few genes on proximal 18q that we know have an effect when one copy is missing. In other words, we cannot link most of the genes on proximal 18q with specific health or developmental concern. As we learn more about the genes on chromosome 18, we will be able to make better predictions about what to expect based on a person’s specific deletion. Families and physicians are able to keep track of the latest information about the genes on chromosome 18 through the Gene Dosage map.

Below, we have included information about significant genes on proximal 18q that we know are associated with significant health concerns when deleted.

SETBP1: Expressive Speech Delay and Intellectual Disability
This gene is located in chromosome band 18q12.3. It is believed that this gene is responsible for significant delays in expressive speech. In other words, people who are missing this gene often have discrepancies in what they can understand and what they are able to express through speech. They often are able to understand more than they can verbally indicate. Deletions of this gene may contribute to the intellectual disability that is associated with proximal 18q-.

Of interest, small changes, called point mutations, in SETBP1 cause a condition called Schinzel-Giedion syndrome. This condition causes significant medical problems, and many babies with this condition do not survive infancy. It is important to note that Schinzel-Giedion syndrome is not the same condition as proximal 18q-. Although people with proximal 18q- may be missing the SETBP1 gene, it is not the same kind of genetic change as the one associated with Schinzel-Giedion syndrome.