CNOT3-related syndrome happens when there are changes to the CNOT3 gene. These changes can keep the gene from working as it should.

Each family is different. A geneticist or genetic counselor can give you advice on the chance that this will happen again in your family.

The risk of having another child who has CNOT3-related syndrome depends on the genes of both birth parents.

• If neither birth parent has the same gene change found in their child, the chance of having another child who has the syndrome is on average 1 percent. This 1 percent chance is higher than the chance of the general population. The increase in risk is due to the very unlikely chance that more of the mother’s egg cells or the father’s sperm cells carry the same change in the gene.
• If one birth parent has the same gene change found in their child, the chance of having another child who has the syndrome is 50 percent.

For a symptom-free sibling, a brother or sister, of someone who has CNOT3-related syndrome, the risk of having a child who has the syndrome depends on the symptom-free sibling’s genes and their parents’ genes.

• If neither parent has the same gene change found in their child who has the syndrome, the symptom-free sibling has a nearly 0 percent chance of having a child who has CNOT3-related syndrome.
• If one birth parent has the same gene change found in their child who has the syndrome, the symptom-free sibling has a small chance of also having the same gene change. If the symptom-free sibling has the same gene change as their sibling who has the syndrome, the symptom-free sibling’s chance of having a child who has CNOT3-related syndrome is 50 percent.

For a person who has CNOT3-related syndrome, the risk of having a child who has the syndrome is about 50 percent.

As of 2019, about 16 people in the world with changes in the CNOT3 gene had been described in the medical literature. The first case of CNOT3-related syndrome was described in 2017. Scientists expect to find more people who have the syndrome as access to genetic testing improves.

Of the 16 people described so far that have CNOT3-related syndrome, 8 people have changes that block the function of the CNOT3 gene. The other 8 people have changes that modify the gene but may not completely block its function. This type of change is called a missense change. Three of the people in the missense group have a change in the same location on the CNOT3 gene. Scientists are studying these changes to learn more about their effects on how the gene works.

People who have CNOT3-related syndrome do not look very different.

Scientists and doctors have only just begun to study CNOT3-related syndrome. At this point, there are no medicines designed to treat the syndrome. A genetic diagnosis can help people decide on the best way to track the condition and manage therapies. Doctors can refer people to specialists for:

• Physical exams and brain studies.
• Genetics consults.
• Development and behavior studies.
• Other issues, as needed.

A developmental pediatrician, neurologist, or psychologist can follow progress over time and can help:

• Suggest the right therapies. This can include physical, occupational, speech, or behavioral therapy.
• Guide individualized education plans (IEPs).

Specialists advise that therapies for CNOT3-related syndrome should begin as early as possible, ideally before a child begins school.

If seizures happen, consult a neurologist. There are many types of seizures, and not all types are easy to spot. To learn more, you can refer to resources such as the Epilepsy Foundation’s website: www.epilepsy.com/learn/types-seizures.

Learning

Everyone who has CNOT3-related syndrome has some degree of learning disability, ranging from mild to severe.

Muscle tone

People who have CNOT3-related syndrome often have low muscle tone.