GENE GUIDE

CHD8-Related Syndrome

This guide is not meant to take the place of medical advice. Please consult with your doctor about your genetic results and health care choices. This Gene Guide was last updated on 2024. As new information comes to light with new research we will update this page. You may find it helpful to share this guide with friends and family members or doctors and teachers of the person who has CHD8-Related Syndrome.
a doctor sees a patient

CHD8-related syndrome is also called CHD8-related neurodevelopmental disorder with overgrowth. For this guide, we will be using the name CHD8-related syndrome to encompass the wide range of variants observed in the people identified.

CHD8-related syndrome happens when there are changes to the CHD8 gene. These changes can keep the gene from working as it should.

Key Role

The CHD8 gene plays a key role in brain growth and function.

Symptoms

Because the CHD8 gene is important in the development and function of brain cells, many people who have CHD8-related syndrome have:

  • Developmental delay, intellectual disability, or both
  • Autism or features of autism
  • Speech delay
  • Characteristic facial profile
  • Gastrointestinal issues, mostly constipation
  • Sleep issues
  • Seizures
  • Attention problems

CHD8-related syndrome is a genetic condition, which means that it is caused by variants in genes. Our genes contain the instructions, or code, that tell our cells how to grow, develop, and work. Every child gets two copies of the CHD8 gene: one copy from their mother’s egg, and one copy from their father’s sperm. In most cases, parents pass on exact copies of the gene to their child. But the process of creating the egg or sperm is not perfect. A change in the genetic code can lead to physical issues, developmental issues, or both. 

Sometimes a spontaneous variant happens in the sperm, egg or after fertilization. When a brand new genetic variant happens in the genetic code is called a ‘de novo’ genetic variant. The child is usually the first in the family to have the genetic variant.

De novo variants can take place in any gene. We all have some de novo variants, most of which don’t affect our health. But because CHD8 plays a key role in development, de novo variants in this gene can have a meaningful effect. 

Research shows that CHD8-related syndrome is often the result of a de novo variant in CHD8. Many parents who have had their genes tested do not have the CHD8 genetic variant found in their child who has the syndrome. In some cases, CHD8-related syndrome happens because the genetic variant was passed down from a parent.

Autosomal dominant conditions

CHD8-related syndrome is an autosomal dominant genetic condition. This means that when a person has the one damaging variant in CHD8 they will likely have symptoms of CHD8-related syndrome. For someone with an autosomal dominant genetic syndrome, every time they have a child there is a 50 percent chance they pass on the same genetic variant and a 50 percent chance they do not pass on the same genetic variant.

Autosomal Dominant Genetic Syndrome

GENE / gene
GENE / gene
Genetic variant that happens in sperm or egg, or after fertilization
GENE / gene
Child with de novo genetic variant
gene / gene
Non-carrier child
gene / gene
Non-carrier child

No parent causes their child’s CHD8-related syndrome. We know this because no parent has any control over the gene changes that they do or do not pass on to their children. Please keep in mind that nothing a parent does before or during the pregnancy causes this to happen. The gene change takes place on its own and cannot be predicted or stopped.

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 CHD8-related syndrome depends on the genes of both biological parents. 

  • If neither biological parent has the same genetic variant 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 genetic variant. 
  • If one biological parent has the same genetic variant found in their child, the chance of having another child who has the syndrome is 50 percent. 

For a symptom-free brother or sister of someone who has CHD8-related syndrome, the sibling’s risk of having a child who has CHD8-related syndrome depends on the sibling’s genes and their parents’ genes. 

  • If neither parent has the same genetic variant causing CHD8-related syndrome, the symptom-free sibling has a nearly 0 percent chance of having a child who would inherit CHD8-related syndrome. 
  • If one biological parent has the same genetic variant causing CHD8-related syndrome, the symptom-free sibling has a 50 percent chance of also having the same genetic variant. If the symptom-free sibling has the same genetic variant, their chance of having a child who has the genetic variant is 50 percent. 

For a person who has CHD8-related syndrome, the risk of having a child who has the syndrome is about 50 percent.

As of 2024, at least 163 people with CHD8-related syndrome have been identified in a medical clinic. Just over 115 people have been described in detail in medical publications. The first case of CHD8-related syndrome was described in 2012.

People with CHD8-related syndrome may look different. Appearance can vary and can include, but is not limited to, these features:

  • Overgrowth, like tall height
  • Larger than average head size
  • Large forehead
  • Wide-set eyes
  • Broad nose
  • Pointed chin
  • Large and or posteriorly rotated ears

Scientists and doctors have only just begun to study CHD8-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 CHD8-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: epilepsy.com/learn/types-seizures.

This section includes a summary of information from major published articles. It highlights how many people have different symptoms. To learn more about the article, see the Sources and references section of this guide.

Behavior

Most people who have CHD8-related syndrome have autism. Some people have anxiety, attention problems, aggression, and temper tantrums.

  • About 80 percent of people have autism.
  • 29 percent of people have anxiety.
  • 50 percent of people have attention problems.
80%
Of people have autism.
29%
Of people have anxiety.
50%
Of people have attention problems.

Sleep

Many people have sleep problems, including difficulties falling asleep. Two children were found to remain awake for days without sleeping.

  • 67 percent of people have difficulties falling asleep.

Learning

Most people have intellectual disability, ranging from mild to severe, and will need special educational support. Most people have some level of speech and motor delay, and about one-half of people report having a regression of social, speech, or motor issues in early childhood.

  • 75-80 percent have intellectual disability, ranging from mild to severe.

Brain

Some people with CHD8-related syndrome have seizures.

  • 12 percent have seizures.

Growth

Many people with CHD8-related syndrome have a larger than average head size observed at birth, or are much taller for their age, often most apparent during puberty. Some people have low muscle tone.

  • 80 percent of people have larger than average head size observed at birth.
  • 27 percent have low muscle tone.

Some people are overweight. More often, people have a slender appearance.

  • 3 out of 14 people are overweight (21 percent).
80%
Of people have larger than average head size observed at birth.
27%
Have low muscle tone.
21%
3 out of 14 people are overweight.

Feeding and digestion issues

Many people have gastrointestinal problems, including constipation, followed by loose stool or diarrhea.

  • 67 percent loose stool or diarrhea.

Where can I find support and resources?

CHD8 Facebook family group

This Facebook group was created to connect families who have children with changes to the CHD8 gene. The group includes researchers at the University of Washington as well as families.

Simons Searchlight

Simons Searchlight is an online international research program, building an ever growing natural history database, biorepository, and resource network of over 175 rare genetic neurodevelopmental disorders. By joining their community and sharing your experiences, you contribute to a growing database used by scientists worldwide to advance the understanding of your genetic condition. Through online surveys and optional blood sample collection, they gather valuable information to improve lives and drive scientific progress. Families like yours are the key to making meaningful progress. To register for Simons Searchlight, go to the Simons Searchlight website at www.simonssearchlight.org and click “Join Us.”

Sources and References

The content in this guide comes from published studies about CHD8-related syndrome. Below you can find details about each study, as well as links to summaries or, in some cases, the full article.

Stay connected with Simons Searchlight

Join our newsletter to receive updates