Families

ARHGEF9 syndrome is a rare genetic condition that can affect how a child grows, learns, and interacts with the world. Children with changes (mutations) in the ARHGEF9 gene may experience developmental delays, learning challenges (sometimes called intellectual disability), and seizures or epilepsy. Many also show differences in brain activity on EEG, even when not having seizures. Sleep difficulties are common, and some children may display behaviors similar to autism, anxiety, or hyperactivity.

This condition is linked to the X chromosome, which means it can affect boys and girls differently. In girls, the symptoms can vary depending on how their cells use the two X chromosomes—a process called X-inactivation. Some girls who carry the gene change may show symptoms, while others may not. In some families, the change in the gene is inherited from a mother who doesn’t show signs herself. More often, however, the gene change happens as a new (de novo) event.

Researchers have identified over 30 different kinds of changes in the ARHGEF9 gene, ranging from very small to larger deletions or rearrangements. Although this condition is still considered rare—with around 60 known cases worldwide as of 2024—new reports are emerging, and ARHGEF9 is becoming recognized as a more common cause of X-linked developmental differences.

While every child’s journey is unique, many families find strength in connecting with others and staying informed. Continued research and awareness are helping to provide better understanding, support, and care for those affected.