GENE GUIDE

TANC2-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 TANC2-Related Syndrome.
a doctor sees a patient

TANC2-related syndrome happens when there are changes to the TANC2 gene. These changes can keep the gene from working as it should.

Key Role

The TANC2 gene helps to control the connections between brain cells.

Symptoms

Because the TANC2 gene is important in the development and function of brain cells, many people who have TANC2-related syndrome have:

  • Autism
  • Intellectual disability
  • Delayed language
  • Delayed motor development
  • Seizures

Our genes contain the instructions, or code, that tell our cells how to grow, develop, and work. Every child gets two copies of the TANC2 gene: one copy from their mother, from the egg, and one copy from their father, from the sperm. In most cases, parents pass on exact copies of the gene to their child. But the process of copying genes is not perfect. A change in the genetic code can lead to physical issues, developmental issues, or both.

Sometimes a random change happens in the sperm or egg. This change to the genetic code is called a ‘de novo’, or new, change. The child can be the first in the family to have the gene change.

De novo changes can take place in any gene. We all have some de novo changes, most of which don’t affect our health. But because TANC2 plays a key role in development, de novo changes in this gene can have a meaningful effect.

Research shows that TANC2-related syndrome is often the result of a de novo change in TANC2. Many parents who have had their genes tested do not have the TANC2 gene change found in their child who has the syndrome. In some cases, TANC2-related syndrome happens because the gene change was passed down from a parent. This is called dominant inheritance.

Child who has genetic change in TANC2 gene

Genetic change occurs in egg or sperm after fertilization
Child with de novo genetic change in autism gene

Why does my child have a change in the TANC2 gene?

No parent causes their child’s TANC2-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 TANC2-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 TANC2-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 TANC2-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 TANC2-related syndrome is 50 percent.

For a person who has TANC2-related syndrome, the risk of having a child who has the syndrome is about 50 percent.

As of 2019, about 20 people in the world with changes in the TANC2 gene had been described in medical research. The first case of TANC2-related syndrome was described in 2019. Scientists expect to find more people who have the syndrome as access to genetic testing improves.

People who have TANC2-related syndrome may look different. Some people have changes in how their teeth are spaced. A few have a smaller than average head size.

  • 3 out of 18 have smaller than average head size.
  • 6 out of 11 have changes in how their teeth are spaced
17%
3 out of 18 have smaller than average head size.
55%
6 out of 11 have changes in how their teeth are spaced.

Scientists and doctors have only just begun to study TANC2-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 TANC2-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/l

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

Learning

Most people who had TANC2-related syndrome had some degree of intellectual disability.

  • 19 out of 20 people had intellectual disability.

Behavior

  • 15 out of 20 people had autism or features of autism.
  • 13 out of 19 people had repetitive behaviors.
  • 6 out of 16 people had aggressive behaviors.
  • 5 out of 13 people had sleep issues.

Speech

Most people had speech delays.

  • 18 out of 20 people had speech delays.

Mental health

  • 4 out of 12 people had anxiety.
75%
15 out of 20 people had autism or features of autism.
68%
13 out of 19 people had repetitive behaviors.
38%
6 out of 16 people had aggressive behaviors.
38%
5 out of 13 people had sleep issues.
95%
19 out of 20 people had an intellectual disability.
90%
18 out of 20 people had speech delays.
33%
4 out of 12 people had anxiety.

Brain

  • 11 out of 20 of those who had TANC2- related syndrome had seizures.

Sitting and walking

  • 13 out of 19 people had motor delays in childhood.

Motor concerns

  • 5 out of 13 people had balance and coordination issues.

Muscle tone 

  • 5 out of 13 people had low muscle tone.

Joints and spine

  • 5 out of 14 people had spinal issues.
  • 3 out of 9 people had joints that were more mobile than average.

Feeding and digestion issues

  • 9 out of 15 people had chronic constipation.
68%
13 out of 19 had motor delays in childhood.
38%
5 out of 13 people had balance and coordination issues.
38%
5 out of 13 people had low muscle tone.
36%
5 out of 14 had spinal issues.
33%
3 out of 9 people had joints that were more mobile than average.
55%
11 out of 20 of people had seizures.
60%
9 out of 15 people had chronic constipation.

Where can I find support and resources?

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 a published study about TANC2-related syndrome. Below you can find details about the study, as well as a link to the full article

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