ANKRD11-Related Syndrome
ANKRD11-related syndrome is also called KGB syndrome. For this webpage, we will be using the name ANKRD11-related syndrome to encompass the wide range of variants observed in the people identified.
What is ANKRD11-related syndrome?
ANKRD11-related syndrome happens when there are changes in the ANKRD11 gene. These changes can keep the gene from working as it should.
Key Role
The ANKRD11 gene plays a key role in the growth of the brain and bones. It’s also important for the growth of new cells and for connections between brain cells.
Symptoms
Because the ANKRD11 gene is important in the development and function of brain cells, many people who have ANKRD11-related syndrome have:
- Intellectual disability and developmental delay
- Behavioral issues
- Large upper front teeth, also called macrodontia, and other unusual facial features
- Skeletal differences, such as a curved spine and shortened fingers, shortened toes, or both
- Small head size, also called microcephaly
- Heart structure defects
- Seizures
What causes ANKRD11-related syndrome?
ANKRD11-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 ANKRD11 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 ANKRD11 plays a key role in development, de novo variants in this gene can have a meaningful effect.
Research shows that ANKRD11-related syndrome is often the result of a de novo variant in ANKRD11. Many parents who have had their genes tested do not have the ANKRD11 genetic variant found in their child who has the syndrome. In some cases, ANKRD11-related syndrome happens because the genetic variant was passed down from a parent.
Autosomal dominant conditions
ANKRD11-related syndrome is an autosomal dominant genetic condition. This means that when a person has the one damaging variant in ANKRD11 they will likely have symptoms of ANKRD11-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
Why does my child or I have a change in the ANKRD11 gene?
No parent causes their child’s ANKRD11-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 ANKRD11-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 ANKRD11-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 ANKRD11-related syndrome, the sibling’s risk of having a child who has ANKRD11-related syndrome depends on the sibling’s genes and their parents’ genes.
- If neither parent has the same genetic variant causing ANKRD11-related syndrome, the symptom-free sibling has a nearly 0 percent chance of having a child who would inherit ANKRD11-related syndrome.
- If one biological parent has the same genetic variant causing ANKRD11-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 ANKRD11-related syndrome, the risk of having a child who has the syndrome is about 50 percent.
How many people have ANKRD11-related syndrome?
As of 2026, over 340 people with ANKRD11-related syndrome have been described in medical research. The first person was found in 1975. Scientists expect to find more people who have the syndrome as access to genetic testing improves.
Do people who have ANKRD11-related syndrome look different?
People with ANKRD11-related syndrome may look different. Appearance can vary and can include, but is not limited to, these features:
- Wide-set eyes
- Triangle-shaped face
- Eyebrows that connect and are broad or bushy
- Noticeable bridge of the nose
- A larger distance between the lip and the upper lip and the nose
- Noticeable nose
How is ANKRD11-related syndrome treated?
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 ANKRD11-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 articles, see the Sources and references section of this guide.
Behavior and development concerns linked to ANKRD11-related syndrome
More males with ANKRD11-related syndrome have been identified than females. Sometimes, a mildly affected mother with ANKRD11-related syndrome was identified only after a son was diagnosed. Research suggests that females with ANKRD11-related syndrome are underdiagnosed because they are more often mildly affected.
Learning and speech
Most children with ANKRD11-related syndrome had some developmental delay and speech delay. The average age of walking was 21 months, and the first words were at 3 years old.
Many, but not all, adults with ANKRD11-related syndrome had intellectual disability. Ability ranged from moderate intellectual disability to normal intellectual abilities. Some adults were able to live independently and have families.
- 176 out of 184 people had developmental delay (96 percent)
- 194 out of 223 people had intellectual disability (87 percent)
- 160 out of 187 people had speech delay (86 percent)
The severity of intellectual disability (ID) varied among people:
- 11 out of 84 people had borderline ID (13 percent)
- 38 out of 84 people had mild ID (45 percent)
- 31 out of 84 people had moderate ID (37 percent)
- 4 out of 84 people had severe to profound ID (5 percent)
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Behavior
About one-half of people with ANKRD11-related syndrome had behavior issues, including anxiety, social challenges, autism, attention-deficit/hyperactivity disorder (ADHD), obsessions, and routine rigidity.
- 56 out of 170 people had autism (33 percent)
- 61 out of 133 people had ADHD (46 percent)
Brain
People with ANKRD11-related syndrome had neurological medical issues, such as abnormal electroencephalogram (EEG) findings with or without seizures, low muscle tone (hypotonia), and brain changes seen on magnetic resonance imaging (MRI). Most people who had seizures were able to manage them with medication, and some people had seizures go away after their teen years.
- 29 out of 67 people had hypotonia (43 percent)
- 60 out of 117 people had brain changes on MRI (51 percent)
- 73 out of 216 people had seizures (34 percent)
Medical and physical concerns linked to ANKRD11-related syndrome
Vision and hearing
People with ANKRD11-related syndrome had vision issues, hearing loss, and recurrent ear infections.
- 69 out of 147 people had vision issues (47 percent)
- 66 out of 188 people had hearing loss (35 percent)
Growth issues
Most people with ANKRD11-related syndrome had issues with growth and development, such as heart structure defects, changes in their teeth and facial features, skeletal changes, shorter than average height, and growth delays.
Heart structure defects have included a hole in the heart (atrial septal defect or ventricular septal defect).
Teeth changes often included the front two teeth being much larger than average.
Common facial changes in people with ANKRD11-related syndrome included wide-set eyes, a triangle-shaped face, eyebrows that connect and are broad or bushy, and a flat back part of the skull.
Skeletal changes included spine and rib defects; sideways curve of the spine, also called scoliosis; and skull shape changes.
A few people had early puberty. Research suggests that some people with ANKRD11-related syndrome who are diagnosed with short height might benefit from human growth hormone therapy.
- 71 out of 199 people had heart structure defects (36 percent)
- 168 out of 179 people had teeth changes (94 percent)
- 178 out of 178 people had face changes (100 percent)
- 196 out of 216 people had skeletal changes (91 percent)
- 111 out of 221 people had a shorter than average height (50 percent)
- 205 out of 220 people had growth delays (93 percent)
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Where can I find support and resources?
KBG Foundation
The KBG Foundation is dedicated to providing support, assisting in research programs and advocating to raise awareness about KBG syndrome.
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 ANKRD11: www.simonssearchlight.org/research/what-we-study/ankrd11
Simons Searchlight ANKRD11 Facebook group: www.facebook.com/groups/searchlight.ankrd11
Sources and References
The content in this guide comes from published articles about ANKRD11-related syndrome. Below you can find details about the articles, as well as links to the full articles.
- Aukema, S. M., Vandenput, K., Scarano, E., Goel, H., Guo, L., Vanneste, M., Devriendt, K., Zwaveling-Soonawala, N., Kiewert, C., … & Ockeloen, C. W. (2025). Growth hormone treatment in patients with KBG syndrome: Novel insights, challenges and recommendations from six new patients and literature review. American Journal of Medical Genetics Part A, 197(12), e64168. doi:10.1002/ajmg.a.64168
- Martinez-Cayuelas, E., Blanco-Kelly, F., Lopez-Grondona, F., Swafiri, S. T., Lopez-Rodriguez, R., Losada-Del Pozo, R., Mahillo-Fernandez, I., Moreno, B., Rodrigo-Moreno, M., … & Almoguera, B. (2023). Clinical description, molecular delineation and genotype-phenotype correlation in 340 patients with KBG syndrome: Addition of 67 new patients. J Med Genet, 60(7), 644-654. doi:10.1136/jmg-2022-108632
- Morel Swols, D., & Tekin, M. KBG syndrome. 2018 Mar 22. In: Adam MP, Bick S, Mirzaa GM, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2026. Available from: https://www.ncbi.nlm.nih.gov/books/NBK487886/
- Wang, Y., Peng, X., Zhu, J., Zou, N., Yu, X., & Yang, L. (2025). KBG syndrome complicated with chylothorax in a newborn: A case report and literature review. Frontiers in Pediatrics, 13, 1690056. doi:10.3389/fped.2025.1690056