Below is a summary for the KANSL1 gene observed in research publications. This is not meant to take the place of medical advice.

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What is KANSL1-related syndrome?

KANSL1-related syndrome happens when there are changes to the KANSL1 gene. These changes can keep the gene from working as it should.

Some people have a change that affects only the KANSL1 gene. Other people are missing a larger piece of DNA that includes the KANSL1 gene.

KANSL1-related syndrome is also called 17q21 deletion syndrome because the KANSL1 gene is found on chromosome 17, one of the body’s 46 chromosomes. Both syndromes share the same set of symptoms. These syndromes are also known as Koolen-de Vries syndrome.

Key Role

The KANSL1 gene helps control other genes during brain development.


Because the KANSL1 gene is important in the development and function of brain cells, many people who have KANSL1-related syndrome have:

  • Developmental delay
  • Intellectual disability
  • Low muscle tone
  • Language issues

Do people with KANSL1-related syndrome look different?

People who have KANSL1-related syndrome may look different. Appearance can vary and can include some but not all of these features:

  • Long face
  • Pear-shaped nose with a round tip
  • Large ears
  • The opening between the eyelids may be narrow or slant upward
  • Drooping eyelids
  • A skin fold covering the inner corner of the eye


Everyone in the study that has KANSL1-related syndrome has developmental delay and intellectual disability. Intellectual disability is mild in 42 percent, moderate in 37 percent, and severe in 22%.



Most people who have KANSL1-related syndrome are sociable. 57 percent of those in the study have behavior issues. This includes autism, attention deficit hyperactivity disorder, shyness, anxiety or phobias, impulsive and repetitive behavior, psychosis, and depression.


Muscle Tone

86 percent of babies who have KANSL1-related syndrome have low muscle tone. This can lead to feeding challenges.


Support Resources



GeneReviews are a great resource to bring to your child’s clinicians. These publications provide a summary of current research on genetic conditions and information on ongoing care.

Check out the GeneReview for KANSL1.


Research Article Summaries

We currently do not have any article summaries for KANSL1, but we add resources to our website as they become available.

The information available about KANSL1 is limited, and families and doctors share a critical need for more information. As we learn more from children who have this gene change, we expect our list of resources and information to grow.

Full versions of published research articles can be found on PubMed. PubMed is a National Institutes of Health (NIH) online database that is free. It has a collection of both medical and scientific research articles. A PubMed search for KANSL1 articles can be found here.


Research Opportunities

Simons Searchlight

Help the Simons Searchlight team learn more about KANSL1 genetic changes by taking part in our research. You can learn more about the project and sign up here.


Family Stories

We do not currently have any stories from KANSL1 families.

Click here to share your family’s story!


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