Will I Have Another Child With Angelman Syndrome?
If you have a child with Angelman syndrome, you may have concerns about whether any future children will be at risk of also inheriting the neurological disease.
Speaking with a genetic counselor is the best way to determine the risks in each specific case, and to discuss your reproductive options.
How does a child develop Angelman syndrome?
Although Angelman is a genetic disease, the majority of cases occur as a result of mutations and not heredity. These mutations, or errors, can occur either when the parental sperm and egg are formed, or just after the sperm and egg combine to create an embryo.
We all inherit two copies of almost every gene, one from each parent. However, not every copy of our genes is active in every cell. For example, only the maternal copy of a gene known as ubiquitin protein ligase E3A (UBE3A) is active in some parts of the brain. The paternal copy is inactive. If children inherit a normal copy of UBE3A from their fathers, but the maternal copy has a mutation, they will have Angelman syndrome.
Some types of chromosomal rearrangement during the formation of an embryo can cause deletions or duplications of chromosomes. The deletion of a part of chromosome 15, which contains UBE3A, also can cause Angelman.
One of the other known causes of Angelman syndrome is imprinting errors. Imprinting in genetics refers to the markering of the DNA regulating which genes are active. If cells accidentally copy paternal imprinting onto the maternal copy of UBE3A, then both copies of the gene become inactive. In that case, the child will have Angelman syndrome.
A very rare cause of Angelman is a child inheriting two copies of the gene from the father, instead of one from each parent. This is called paternal uniparental disomy. Because both copies are paternal, they are both inactive in important areas in the brain.
Around 10-15% of Angelman syndrome cases have no known cause. Therefore, it’s difficult to say whether or not a child could inherit the disease.
What is the risk of another child inheriting Angelman?
Because the inheritance of Angelman syndrome is so complex, you should discuss your family medical history with a genetic counselor. A counselor can help you determine the risks in your specific case.
Genetic testing can determine if you and your partner are carriers of any deletions that may cause Angelman syndrome. Carriers of genetic diseases generally have no symptoms of the disorders, but can pass them on to their children.
The genetic counselor can discuss your child’s genetic test results. If the disease is the result of a chromosomal rearrangement, or an error that occurred during development, it’s very unlikely that any future children also would have Angelman syndrome.
What are my reproductive options?
If your child with Angelman inherited the disease from you and your partner, you may be able to minimize the risk of future children inheriting it. Reproductive technologies such as in vitro fertilization, known as IVF, and pre-implantation genetic diagnosis may provide some options. These options may prove useful for mothers who are carriers of a mutation in the UBE3A gene. It would not be effective in preventing other causes of Angelman syndrome, however.
Scientists note that there also may be a higher risk of Angelman in children conceived through IVF techniques, although the reasons for this are not known.
If you have concerns about your baby inheriting Angelman syndrome, you can have genetic tests done before the child is born. However, again, 10-15% of Angelman syndrome cases are not detectable by current genetic tests.
It’s a good idea to discuss your options with your family doctor and a genetic counselor. They can help you understand the potential risks to future children. They also can help you choose reproductive options that minimize that risk.
Last updated: July 10, 2020
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