Mucopolysaccharidosis Type VI

As of December 21st, 2015, there are no newborn screening programs that test for mucopolysaccharidosis type VI. However, some laboratories may begin trial testing for these conditions in the future to see if a newborn screening test for mucopolysaccharidosis type VI would be useful.

A "variant" is another word for a change in a gene. Sometimes these changes are not associated with causing a genetic disease or condition, and other times they are. Variants can be benign (not disease-causing), pathogenic (disease-causing), or of unknown significance (possibly disease-causing). Looking at a person's genetic testing report can be helpful to know what type of variant or genetic change someone has inherited for Mucopolysaccharidosis Type VI. If a person has Mucopolysaccharidosis Type VI, they have two different disease-causing (pathogenic) variants in their ARSB genes.

While Mucopolysaccharidosis Type VI (MPS VI) is relatively rare, it can run in families and be passed from parents to children. The way that it is passed down is called autosomal recessive inheritance. This means that in order to develop symptoms of MPS VI, a person must have inherited two non-working copies of the ARSB gene, which is the gene associated with this condition. If a person has one working copy and one non-working copy, they are a carrier for MPS VI but do not have any symptoms themselves. We assume that both parents of an affected person are carriers, so each of their children has a 1 in 4 or 25% chance of having MPS VI as well. Because of the skeletal problems that people with MPS VI have, it is usually easy to tell if one of your adult family members could have this genetic condition. Testing the brothers and sisters of someone who has MPS VI is important because it can find out who is a carrier and who is also affected by MPS VI (for example, a baby that may not have visible symptoms yet). The aunts and uncles of people with MPS VI may also be carriers. If other people in the family want to know their chances to have a baby with MPS VI, they can be tested for the same gene changes as the person diagnosed with MPS VI.

To find a genetic professional near you who can discuss genetic testing, visit the following two sites: A listing of medical geneticists can be found at the American College of Medical Geneticists website (www.acmg.net) and genetic counselors can be found on the National Society of Genetic Counselors website: www.nsgc.org.

In Mucopolysaccharidosis Type VI, the arylsulfatase B enzyme is not working properly. Testing for the enzyme level is best performed in a blood sample. Genetic testing can sometimes be done on a saliva sample, but there is a possibility of not being able to get enough DNA, or genetic information, from the saliva sample to do the testing, especially for multiple gene panel testing.

For more information about genetic testing options, including panel testing, go to GeneTests.org.

The first step in testing is usually a urine test to look for certain substances called glycosaminoglycans (GAGs) and to see if a substance called dermatan sulfate is high. At the same time, they may test your blood to check the level of arylsulfatase B enzyme (the enzyme that isn't working properly in MPS VI). These two tests together can figure out if a person has MPS VI. Another way to test for MPS VI is by doing a genetic test that looks for changes in the ARSB gene, which gives the instructions to make arylsulfatase B.

To find a genetic professional near you who can discuss genetic testing, visit the following two sites: A listing of medical geneticists can be found at the American College of Medical Geneticists website (www.acmg.net) and genetic counselors can be found on the National Society of Genetic Counselors website: www.nsgc.org.