If you know you are a carrier of adrenoleukodystrophy (ALD), or if you or your partner has ALD, you may want to speak with a genetic counselor about your pregnancy plans and risk of passing the disease to your children. They will be able to talk about this risk, and about alternative reproductive options you might consider.
Carriers of a genetic disease generally have a single copy of the mutated gene. They do not have any symptoms of the disease themselves.
Mutations on a gene situated on the X-chromosome (one of two sex-determining chromosomes) cause ALD. Women have two X-chromosomes, while men have one X-chromosome and one Y-chromosome. ALD primarily affects men. However, women can also develop the disease if they have one or two copies of the disease-causing mutation.
Males with ALD need to inherit a single copy of the disease-causing mutation from their mother. Females usually need to inherit a copy of the mutation from both parents. However, in rare cases, inheriting a single copy of a disease-causing mutation can cause the disease, even in girls.
Prenatal screens
Most people with ALD (and carriers) can conceive naturally. However, hematopoietic stem cell transplantation (HSCT), a treatment for ALD, can severely affect fertility. If you or your partner have had this treatment, you may want to consider in vitro fertilization (IVF).
If you choose to conceive naturally, your baby can undergo genetic testing while still in the uterus to determine whether they inherited the faulty gene (in ALD, it’s the ABCD1 gene). In order to obtain a genetic sample from the fetus, doctors can use either amniocentesis or chorionic villus sampling (CVS).
Amniocentesis involves collecting a sample of the fluid that surrounds the fetus in the uterus (amniotic fluid). This fluid contains cells from the fetus, which doctors use for genetic testing. The doctor will collect a sample of the amniotic fluid by inserting a syringe needle through the abdomen and into the uterus.
Another way of obtaining genetic material from the fetus is to take a sample of the placenta. The doctor will collect this sample by inserting a needle through the mother’s abdomen or vagina.
In vitro fertilization (IVF)
In IVF, sperm cells fertilize egg cells and form an embryo in a laboratory dish. Doctors then implant the embryo in the mother’s uterus. Alternatively, a surrogate can be contracted to carry a child to term if pregnancy would be dangerous for the biological mother.
The IVF process can be done with reproductive material from you and your partner. You can also request donor egg and sperm to reduce the risk that your child will inherit ALD. If you use donor egg and sperm, the child will not be genetically related to you and your partner.
Pre-implantation genetic testing
If you would like to use your own egg and sperm for IVF, the embryos that are created can be genetically tested for ALD before implantation.
A woman who is a carrier of ALD has a 1 in 2 chance of passing the faulty gene to her children.
If the child inherits a Y chromosome from the father (i.e., a male baby), he will have a 1 in 2 chance of having ALD. He will also have a 1 in 2 chance of not inheriting the disease.
If the child inherits an X chromosome from the father (who does not have ALD), the child is female. She will have a 1 in 2 chance of being a carrier like her mother. She will also have a 1 in 2 chance of not inheriting the disease.
A man with ALD will not pass the disease to any of his sons. However, he will pass it to all of his daughters.
Following prenatal genetic testing and diagnosis, you can choose to implant only embryos created by IVF that do not have the disease-causing gene.
Last updated: June 24, 2020
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Adrenoleukodystrophy News is strictly a news and information website about the disease. It does not provide medical advice, diagnosis or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.
