Below is a summary for the AHDC1 gene observed in research publications. This is not meant to take the place of medical advice. Click HERE for the full gene guide, which includes more information, such as the chance of having another child with this condition, or specialists to consider for people with this condition.

What is AHDC1 -related syndrome or Xia-Gibbs syndrome?

Xia-Gibbs syndrome happens when there are changes to the AHDC1 gene. These changes can keep the gene from working as it should. 

Key Role

The AHDC1 gene plays a key role in the growth of the brain.


Because the AHDC1 gene is important in the development and function of brain cells, many people who have Xia-Gibbs syndrome have:

  • Developmental delay
  • Intellectual disability
  • Speech delay
  • Motor delay
  • Difficulty walking
  • Sleep apnea, a disorder in which breathing stops and starts
  • Seizures
  • Hearing difficulty
  • Brain changes seen on magnetic resonance imaging (MRI)

Do people who have Xia-Gibbs syndrome look different?

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

  • Broad forehead
  • Widely spaced eyes
  • Flat bridge of nose
  • Thin upper lip

How many people have AHDC1 – related syndrome?

As of 2023, doctors had found about 79 people in the world with changes in the AHDC1 gene. The first case of AHDC1 -related syndrome was described in 2014. Scientists expect to find more people who have the syndrome as access to genetic testing improves.

  • 40% are nonverbal (all male)
  • 20% use less than 50 words
  • 10% use more than 50 words but do not speak in full sentences
  • 30% use complete sentences and more than 200 words



People often have some level of intellectual disability.


About one-half of those who have the syndrome have sleep apnea, a condition in which people stop breathing during sleep for short periods of time. Some use a breathing aid during sleep. One-quarter have autism or symptoms of autism.




Many children who have the syndrome grow slowly and are shorter than their peers.


Support Resources


Research Article Summaries

Below, we’ve summarized research articles about changes in the AHDC1 gene. We hope you find this information helpful.

The information available about AHDC1 is limited, and families and doctors share a critical need for more information. As we learn more from children who have a change in this gene, we expect this 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 AHDC1 articles can be found here.

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

Research Article Summaries

  • De novo truncating mutations in the AHDC1 gene encoding the AT-hook DNA-binding motif-containing protein 1 are associated with intellectual disability and developmental delay
    • Original research report by H. Yang et al. (2015).
    • Read the report here. Read the Simons Searchlight summary here.
  • De novo truncating mutations in AHDC1 in people with syndromic expressive language delay, hypotonia, and sleep apnea
    • Original research report by F. Xia et al. (2014.)
    • Read the report here. Read the Simons Searchlight summary here.

Research Opportunities

Simons Searchlight

Help the Simons Searchlight team learn more about AHDC1 genetic changes by taking part in our research. You can learn more about the project and sign up here.

External Research Opportunity: FaceMatch

FaceMatch is a platform that helps parents and doctors contribute to an international secure image database of both undiagnosed and diagnosed children across the globe. *This study is not affiliated with Simons Searchlight. Learn more about FaceMatch.


Family Stories

Stories from  AHDC1  families:

Click here to share your family’s story!