- Leukodystrophy metachromatic
- Metachromatic leukoencephalopathy
- Sulfatide lipidosis
- Arylsulfatase A deficiency
Your QuestionMy 2 year old grandson has MLD. So both parents are carriers. I have three other children and 2 of them have one child each. All 3 of my other children are planning to have another child. Who in the family needs to be tested for the carrier gene for MLD? Does a child of a carrier automatically become a carrier as well? Will that carrier gene continue to be passed on and should all my family be tested?
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Questions on this page
- How is metachromatic leukodystrophy inherited?
- Is someone is a carrier for metachromatic leukodystrophy, what are the chances for his/her siblings to be carriers?
- Who might consider genetic carrier testing for a family history of metachromatic leukodystrophy?
- How can I find a genetics professional in my area?
When two carriers of an autosomal recessive condition have children, each child has a 25% (1 in 4) chance to have the condition, a 50% (1 in 2) chance to be a carrier like each of the parents, and a 25% chance to not have the condition and not be a carrier.
If someone has a family history of metachromatic leukodystrophy (MLD) or someone is known to be a carrier for MLD, individuals who are biologically related to the affected individual or carrier are at risk to be a carrier. Generally speaking, the more closely related an individual is to the affected individual or carrier, the greater the chance for that person to be a carrier. Prior to genetic testing, the chance to be a carrier for some biological relatives of an affected individual are as follows:
- Parent of affected individual: assumed to be 100% (called an obligate carrier)
- Unaffected sibling of affected individual: 2 in 3 (~66.6%)
- Aunt or uncle of affected individual: 1 in 2 (50%)
- First cousin of affected individual: 1 in 4 (25%)
If someone has carrier testing and is found to be negative (not a carrier), that person's children are typically assumed to be negative also.
More information about the use of genetic carrier testing is available on GeneTests' Web site and can be viewed by clicking here.
Individuals who are interested in learning about genetic testing and about their specific risk to be a carrier should speak with a genetics professional.
The following online resources can help you find a genetics professional in your community:
- The National Society of Genetic Counselors provides a searchable directory of US and international genetic counseling services.
- The American College of Medical Genetics has a searchable database of US genetics clinics.
- The University of Kansas Medical Center provides a list of US and international genetic centers, clinics, and departments.
- The American Society of Human Genetics maintains a database of its members, which includes individuals who live outside of the United States. Visit the link to obtain a list of the geneticists in your country, some of whom may be researchers that do not provide medical care.