15q24 Deletion Syndrome
15q24 deletion syndrome is also called Witteveen-Kolk syndrome or 15q24 microdeletion syndrome. For this webpage, we will be using the name 15q24 deletion syndrome to encompass the wide range of variants observed in the people identified.
What is 15q24 deletion syndrome?
15q24 deletion syndrome happens when a person has an extra piece of chromosome 15, one of the body’s 46 chromosomes. Chromosomes are structures in our cells that house our genes. The 15q24 deletion piece can affect learning and how the body develops.
Key Role
Genes within the 15q24 region are important for brain development and function.
Symptoms
Because genes in the 15q24 region are important in brain development and function, many people who have 15q24 deletion syndrome have:
- Developmental delay
- Intellectual disability
- Failure to thrive
- Behavioral issues
- Low muscle tone
- Loose joints
- Defects of the eye, limbs, gastrointestinal tract, and genitals in both males and females
What causes 15q24 deletion syndrome?
15q24 deletion 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 15q24 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 15q24 plays a key role in development, de novo variants in this gene can have a meaningful effect.
Research shows that 15q24 deletion syndrome is often the result of a de novo variant in 15q24. Many parents who have had their genes tested do not have the 15q24 genetic variant found in their child who has the syndrome. In some cases, 15q24 deletion syndrome happens because the genetic variant was passed down from a parent.
Autosomal dominant conditions
15q24 deletion syndrome is an autosomal dominant genetic condition. This means that when a person has the one damaging variant in 15q24 they will likely have symptoms of 15q24 deletion 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
Why do I or my child have 15q24 deletion syndrome
No parent causes their child’s 15q24 deletion syndrome. We know this because no parent has any control over the chromosome 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 genetic change takes place on its own and cannot be predicted or stopped.
What are the chances that other family members or future children will have 15q24 deletion 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 15q24 deletion 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 15q24 deletion syndrome, the sibling’s risk of having a child who has 15q24 deletion syndrome depends on the sibling’s genes and their parents’ genes.
- If neither parent has the same genetic variant causing 15q24 deletion syndrome, the symptom-free sibling has a nearly 0 percent chance of having a child who would inherit 15q24 deletion syndrome.
- If one biological parent has the same genetic variant causing 15q24 deletion 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 15q24 deletion syndrome, the risk of having a child who has the syndrome is about 50 percent.
How many people have 15q24 deletion syndrome?
As of 2025, about 55 people with 15q24 deletion syndrome have been described in medical research.
Do people who have 15q24 deletion syndrome look different?
People who have 15q24 deletion syndrome may look different. Appearance can vary and can include some but not all of these features:
- Changes in finger shape
- High hairline
- Changes in ear shape
- Long and smooth dent above the upper lip
- Skin fold covering the inner corner of the eye
- Eyes that slant downwards
- Sparse eyebrows
- Large distance between the eyes
- Crossed eyes
- Full lower lip
- Small mouth
- Long face
How is 15q24 deletion syndrome treated?
Scientists and doctors have only just begun to study 15q24 deletion 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 15q24 deletion 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 major published articles. 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 15q24 deletion syndrome
Learning and speech
People with 15q24 deletion syndrome had developmental delay or intellectual disability, and speech delay or impairment.
- 45 out of 45 people had developmental delay (100 percent)
- 2 out of 45 people had intellectual disability (4 percent)
- 11 out of 45 people had speech delay or impairment (24 percent)
Behavior
People with 15q24 deletion syndrome had behavioral issues, such as autism and attention-deficit/hyperactivity disorder (ADHD). Several people had a happy personality.
- 23 out of 45 people had behavioral issues (51 percent)
- 7 out of 45 people had autism (16 percent)
- 5 out of 45 people had ADHD (11 percent)
Brain
Some people with 15q24 deletion syndrome had neurological medical issues, such as a smaller than average head size (microcephaly), brain changes seen on magnetic resonance imaging (MRI), and lower than average muscle tone (hypotonia).
- 8 out of 45 people had microcephaly (18 percent)
- 14 out of 45 people had brain changes seen on MRI (31 percent)
- 20 out of 45 people had hypotonia (44 percent)
Medical and physical concerns linked to 15q24 deletion syndrome
Vision and hearing issues
Many people with 15q24 deletion syndrome had vision issues, such as crossed eyes (strabismus) and eyes that move rapidly without control (nystagmus). Some had hearing and/or ear defects.
- 8 out of 35 people had vision issues (23 percent)
- 14 out of 48 people had hearing defects (29 percent)
Growth issues
People with 15q24 deletion syndrome had issues with growth and development. They had skeletal changes, such as hypermobile joints, sideways curve of the spine (scoliosis), and defects of the fingers. Few people had genital defects, hernias, or intestinal issues.
- 16 out of 45 people had hypermobile joints (36 percent)
- 10 out of 45 people had scoliosis (22 percent)
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.”
- Learn more about Simons Searchlight: www.simonssearchlight.org/frequently-asked-questions
- Simons Searchlight webpage with more information on 15q24 deletion: www.simonssearchlight.org/research/what-we-study/15q24-deletion
- Simons Searchlight Facebook group: https://www.facebook.com/groups/15q24-deletion
Sources and References
- Liu, Y., Zhang, Y., Zarrei, M., Dong, R., Yang, X., Zhao, D., Scherer, S. W., & Gai, Z. (2020). Refining critical regions in 15q24 microdeletion syndrome pertaining to autism. American Journal of Medical Genetics Part B Neuropsychiatric Genetics, 183(4), 217-226. doi:10.1002/ajmg.b.32778
- Liu, Y., & Mapow, B. (2020). Coexistence of urogenital malformations in a female fetus with de novo 15q24 microdeletion and a literature review. Molecular Genetics & Genomic Medicine, 8(7), e1265. doi:10.1002/mgg3.1265
- Tang, H., Xu, J., Ge, L., Gao, Q., Tan, X., Qiao, Q., Liu, R., Kong, Q., Li, Q., & Jiang, X. (2025). Report on Witteveen-Kolk syndrome caused by large fragment deletion in the 15q24.1 – q24.2 region in infants with early onset and literature review. Italian Journal of Pediatrics, 51(1), 134. doi:10.1186/s13052-025-01971-3