BCL11A-Related Syndrome

BCL11A-related syndrome happens when there are changes in the BCL11A gene. These changes can keep the gene from working as it should.

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 BCL11A-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 BCL11A-related syndrome, the sibling’s risk of having a child who has BCL11A-related syndrome depends on the sibling’s genes and their parents’ genes. 

• If neither parent has the same genetic variant causing BCL11A-related syndrome, the symptom-free sibling has a nearly 0 percent chance of having a child who would inherit BCL11A-related syndrome. 
• If one biological parent has the same genetic variant causing BCL11A-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 BCL11A-related syndrome, the risk of having a child who has the syndrome is about 50 percent.

As of 2026, about 77 people with BCL11A-related syndrome have been described in medical research.

People with BCL11A-related syndrome may look different. Appearance can vary and can include some but not all of these features:

• Underdeveloped cheekbones
• Wide nose
• Thin upper lip
• Thick lower lip
• Ear defects
• Full cheeks

Scientists and doctors have only just begun to study BCL11A-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 BCL11A-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/learn/types-seizures.

Learning and speech

Many people with BCL11A-related syndrome had developmental delay or intellectual disability, and speech and language impairment. The average age of first words was about 2 years old, and some people did not speak at the time of their examination. The average age for walking with or without support was about 2.5 years, although the range was 14 months to 9 years.

• 70 out of 72 people had developmental delay or intellectual disability (97 percent)
• 55 out of 58 people had speech delays (95 percent)

The severity of intellectual disability (ID) varied among people:

• 9 out of 70 people had mild ID (13 percent)
• 24 out of 70 people had moderate ID (34 percent)
• 12 out of 70 people had severe or profound ID (17 percent)
• 25 out of 70 people had an unknown level of ID (36 percent)

Behavior

People with BCL11A-related syndrome had behavioral issues, such as autism, attention-deficit/hyperactivity disorder (ADHD), aggression, anxiety, and repetitive behavior.

• 34 out of 50 people had behavioral issues (68 percent)
• 19 out of 51 people had autism (37 percent)

Brain

Many people with BCL11A-related syndrome had neurological medical issues, such as lower than average muscle tone (hypotonia), smaller than average head size (microcephaly), seizures, brain changes seen on magnetic resonance imaging (MRI), and poor muscle control that causes clumsy movements (ataxia). The average age of seizure onset was about 4 years old, but people developed seizures as young as 5 months and as old as 10 years.

• 35 out of 49 people had hypotonia (71 percent)
• 26 out of 52 people had microcephaly (50 percent)
• 13 out of 53 people had seizures (25 percent)
• 29 out of 49 people had brain changes seen on MRI (59 percent)
• 13 out of 31 people had ataxia (42 percent)

Brain structure changes varied among people, such as abnormal structure in the hind region of the brain (posterior fossa), brain stem, corpus callosum, and cortical regions.

• 17 out of 49 people had posterior fossa defects (35 percent)
• 15 out of 48 people had brain stem defects (31 percent)
• 9 out of 48 people had developmental defects of the corpus callosum (19 percent)
• 2 out of 48 people had cortical defects (4 percent)

Gastrointestinal challenges

People with BCL11A-related syndrome had digestion issues such as constipation.

• 13 out of 33 people had constipation (39 percent)

Vision

Eye issues included, but were not limited to, crossed eyes (strabismus).

• 30 out of 50 people had strabismus (60 percent)

Other developmental features

People with BCL11A-related syndrome had joint hypermobility and sideways curvature of the spine, also called scoliosis. Most with BCL11A-related syndrome had elevated hemoglobin F (HbF) that decreased over their life span but stayed higher than the general population.

• 19 out of 48 people had joint hypermobility (40 percent)
• 8 out of 32 people had scoliosis (25 percent)
• 32 out of 32 people had elevated HbF (100 percent)

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 BCL11A: www.simonssearchlight.org/research/what-we-study/bcl11a

• Simons Searchlight BCL11A Facebook community: https://www.facebook.com/groups/bcl11a