DDX3X Syndrome is a rare disease caused by a spontaneous mutation within a DDX3X gene at conception or can be inherited. The syndrome was discovered in the United States in 2014 and primarily affects girls due to its location on the X-chromosome, though there are some boys it has affected as well. Although it has only been identified in about over 700 individuals, doctors believe it is the cause of 1 to 3 percent of all intellectual disabilities in females. Most girls with DDX3X syndrome have deveolpmental or intellectual disability, behavior problem, including autism and ADHD (attention deficit hyperactivity disorder, and low muscle tone (hypotonia)
DDX3X Syndrome is often misdiagnosed as autism spectrum disorder, cerebral palsy, Rett Syndrome, Dandy-Walker Syndrome, or a generic developmentally delayed label. It is linked to intellectual disabilities, seizures, autism, low muscle tone, abnormalities of the brain, and slower physical developments. It has a broad spectrum—some individuals develop the ability to speak in full sentences, while others are nonverbal. Some individuals run, jump, and even ski, while others are unable to walk.