Alpha-mannosidosis

Newborn screening is a state-run program that screens babies for certain severe medical conditions at birth. Newborn screening is not currently being performed for alpha-mannosidosis. To learn about what conditions are being screened for in different states, visit: http://www.babysfirsttest.org/newborn-screening/states.

More information about newborn screening available in each state is available from the NewSTEPs Newborn Screening Status site, or the U.S. Centers for Disease Control and Prevention in Atlanta, Georgia.

There are different types of tests available to diagnose alpha-mannosidosis. One type of test looks at the levels of the alpha-mannosidase enzyme in the blood or skin cells and can determine if someone may have alpha-mannosidosis. Another way to test for alpha-mannosidosis is by doing a genetic test that looks for specific changes in the MAN2B1 gene in the blood.

Because of the skeletal problems that people with alpha-mannosidosis have, it is usually easy to tell if one of your family members could have this genetic condition; however, some people with alpha-mannosidosis may not have any signs or symptoms at birth. If anyone in your family has signs of alpha-mannosidosis or is a new full sibling to someone with alpha-mannosidosis, genetic testing may be helpful for them. Other people in the family could be carriers of alpha-mannosidosis, and a genetic counseling consultation might benefit them. Genetic counselors can be found on the National Society of Genetic Counselors website.

If you or a family member are diagnosed with alpha-mannosidosis, and genetic testing has confirmed your diagnosis, it is helpful to share your results with your family. A detailed family history can also provide information about which family members are at risk for developing alpha-mannosidosis.

Because most people with alpha-mannosidosis have two genetic changes in their MAN2B1 genes in all of the cells of their body, they would have the same genetic testing results on blood, saliva, or other body tissue from a biopsy. However, most genetic tests for alpha-mannosidosis are done on the blood.

A "variant" is another word for a change in a gene. Sometimes these changes are not associated with causing a genetic disease or condition; 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 alpha-mannosidosis. If a person has alpha-mannosidosis, they have two different disease-causing (pathogenic) variants in their MAN2B1 genes.

Alpha-mannosidosis is caused by a change (variant) in the MAN2B1 gene. Not all changes in a gene necessarily cause disease. If a change is known to cause a disorder, it is known as a pathogenic or disease-causing variant. However, sometimes gene changes are found, and scientists are unsure what it means, either because it has not been found before or it has only been found in a few people. This is known as a variant of unknown significance. If you have a variant of unknown significance in the MAN2B1 gene, talk to your doctor about further testing that may help find out whether the gene change is pathogenic or not. A genetic counselor may also be able to help you review your test results. Genetic counselors in the United States can be found on the National Society of Genetic Counselors website.