CSNK2B-Related Syndrome
CSNK2B-related syndrome is also called Poirier-Bienvenu neurodevelopmental syndrome. For this guide, we will be using the name CSNK2B-related syndrome to encompass the wide range of variants observed in the people identified.
What is CSNK2B-related syndrome?
CSNK2B-related syndrome happens when there are changes in the CSNK2B gene. These changes can keep the gene from working as it should.
Key Role
The CSNK2B gene plays different roles in the body, including cell to cell communication, cell division, and expression of other genes.
Symptoms
Because the CSNK2B gene is important in the development and function of brain cells, many people who have CSNK2B-related syndrome have:
- Seizures
- Developmental delay
- Poor or absent speech
- Autism or features of autism
- Mobility issues
What causes CSNK2B-related syndrome?
CSNK2B-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 CSNK2B 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 CSNK2B plays a key role in development, de novo variants in this gene can have a meaningful effect.
Research shows that CSNK2B-related syndrome is often the result of a de novo variant in CSNK2B. Many parents who have had their genes tested do not have the CSNK2B genetic variant found in their child who has the syndrome. In some cases, CSNK2B-related syndrome happens because the genetic variant was passed down from a parent.
Autosomal dominant conditions
CSNK2B-related syndrome is an autosomal dominant genetic condition. This means that when a person has the one damaging variant in CSNK2B they will likely have symptoms of CSNK2B-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
No parent causes their child’s CSNK2B-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.
What are the chances that other family members of future children will have CSNK2B-related syndrome?
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 CSNK2B-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 CSNK2B-related syndrome, the sibling’s risk of having a child who has CSNK2B-related syndrome depends on the sibling’s genes and their parents’ genes.
- If neither parent has the same genetic variant causing CSNK2B-related syndrome, the symptom-free sibling has a nearly 0 percent chance of having a child who would inherit CSNK2B-related syndrome.
- If one biological parent has the same genetic variant causing CSNK2B-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.
How many people have CSNK2B-related syndrome?
As of 2024, about 77 people with CSNK2B-related syndrome have been described in medical research.
Do people who have CSNK2B-related syndrome look different?
People who have CSNK2B-related syndrome may look different. Appearance can vary and can include some but not all of these features:
- Lower than average muscle tone
- Dental changes
- A tongue that might protrude
- Unique facial features
How is CSNK2B-related syndrome treated?
Scientists and doctors have only just begun to study CSNK2B-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 CSNK2B-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/…t-is-epilepsy/seizure-types
This section includes a summary of information from published articles that describe 67 people with changes in the CSNK2B gene. It highlights how many people have different symptoms. To learn more about the articles, see the Sources and references section of this guide.
Behavior and development concerns linked to CSNK2B-related syndrome
Learning
Most people with CSNK2B-related syndrome had intellectual disability or developmental delay (ID/DD).
61 out of 67 people had intellectual disability (91 percent).
- 20 out of 67 people had severe ID/DD (30 percent)
- 7 out of 67 people had moderate ID/DD (10 percent)
- 34 out of 67 people had mild ID/DD (50 percent)
- 6 out of 67 people had average intelligence (9 percent)
Some people had autism.
- 12 out of 67 people had autism (18 percent)
Brain
Most people had seizures. Some people had a larger than average head size, also called macrocephaly. Others had a smaller than average head size, also called microcephaly.
- 57 out of 67 people had seizures (85 percent)
- 4 out of 67 people had a larger than average head size (6 percent)
- 7 out of 67 people had a smaller than average head size (10 percent)
Other features
About one-quarter of people had failure to thrive or were shorter than average in height.
- 17 out of 67 people had failure to thrive or shorter than average height (25 percent)
Some people with CSNK2B-related syndrome had eye or vision issues, such as farsightedness, eyes that move rapidly without control (nystagmus), or eyelids that are droopy.
Where can I find support and resources?
CSNK2B Neurodevelopmental Syndrome Foundation
Simons Searchlight is another research program sponsored and run by the Simons Foundation Autism Research Initiative, also known as SFARI. As part of the next step in your research journey, Simons Searchlight offers you the opportunity to partner with scientists and other families who have the same gene change. Simons Searchlight is a registry for more than 150 genetic changes that are associated with neurodevelopmental conditions, including autism spectrum disorder. Simons Searchlight makes it easier for researchers to access the information they need to advance research on a condition. To register for Simons Searchlight, go to the Simons Searchlight website at www.simonssearchlight.org and click “Join Us Today”.
Learn more about Simons Searchlight
www.simonssearchlight.org/frequently-asked-questions
Simons Searchlight webpage with more information on CSNK2B
www.simonssearchlight.org/research/what-we-study/csnk2b
Simons Searchlight Facebook group
Sources and References
- Chen, X., Han, Y., Li, X., Huang, S., Yuan, H., & Qin, Y. (2023). Case report: Two cases of Poirier-Bienvenu neurodevelopmental syndrome and review of literature. Frontiers in Pediatrics, 11, 967701. https://pubmed.ncbi.nlm.nih.gov/37020656/
- Di Stazio, M., Zanus, C., Faletra, F., Pesaresi, A., Ziccardi, I., Morgan, A., Girotto, G., Costa, P., Carrozzi, M., d’Adamo, A. P., & Musante, L. (2023). Haploinsufficiency as a foreground pathomechanism of Poirer-Bienvenu syndrome and novel insights underlying the phenotypic continuum of CSNK2B-associated disorders. Genes (Basel), 14(2), 250. https://pubmed.ncbi.nlm.nih.gov/36833176/
- Ernst, M. E., … Aggarwal, V. (2021). CSNK2B: A broad spectrum of neurodevelopmental disability and epilepsy severity. Epilepsia, 62(7), e103-e109. doi:10.1111/epi.16931
- Li, D., Zhou, B., Tian, X., Chen, X., Wang, Y., Hao, S., Zhang, C., & Hui, L. (2024). Genetic analysis and literature review of a Poirier-Bienvenu neurodevelopmental syndrome family line caused by a de novo frameshift variant in CSNK2B. Molecular Genetics & Genomic Medicine, 12(1), e2327. https://pubmed.ncbi.nlm.nih.gov/38037515/