Below is a summary for the AFF2 gene observed in research publications. This is not meant to take the place of medical advice.

Click here for our full AFF2 Gene Guide

The online Gene Guide includes more information about AFF2 such as the chance of having another child with this condition, behavior and development concerns linked to AFF2 or specialists to consider for people with this condition. Share this resource with family members or your clinical providers.

AFF2-related syndrome is also called FMR2 or FRAXE. For this webpage, we will be using the name AFF2-related syndrome to encompass the wide range of variants observed in the people identified.

What is AFF2-related syndrome?

AFF2-related syndrome happens when there are changes to the AFF2 gene. These changes can keep the gene from working as it should. The AFF2 gene is located on the X chromosome and only males carrying the genetic variation are affected with the condition.

Key Role

The AFF2 gene plays a key role in brain development.


Because the AFF2 gene is important in the development and function of brain cells, many people who have AFF2-related syndrome have:

  • Intellectual disability
  • Developmental and speech delays
  • Autism or features of autism 
  • Hyperactivity and attention difficulties
  • Behavior issues, such as aggression, impulsivity, and obsessive compulsive disorder

How many people have AFF2-related syndrome?

Researchers estimate that about 1 in 25,000 to 1 in 100,000 newborn males have AFF2-related syndrome. There are likely many more undiagnosed people who have the syndrome. As of 2024, doctors had described over 50 people in the world with changes in the AFF2 gene. The first case of AFF2-related syndrome was described in 1993. Scientists expect to find more people who have the syndrome as access to genetic testing improves.


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.

There is currently no GeneReviews for AFF2.


Research Article Summaries

We currently do not have any article summaries for AFF2, but we add resources to our website as they become available.

The information available about AFF2 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 AFF2 articles can be found here.

You can also visit the Simons Foundation’s SFARI Gene website to see information for researchers about this gene.


Research Opportunities

Simons Searchlight

Help the Simons Searchlight team learn more about AFF2 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 AFF2 families.

Click here to share your family’s story!