NEUROBEHAVIORAL

Fragile X Syndrome

Fragile X syndrome (FXS), originally known as Martin-Bell syndrome, is a rare genetic disorder that may cause intellectual disability, developmental delays, behavioral and learning challenges, and various physical features. It is the most common inherited cause of intellectual disability and monogenic cause of autism spectrum disorder.

FXS patients are born with a full mutation in the FMR1 (Fragile X Messenger Ribonucleoprotein 1) gene which leads to a deficiency in FMRP (Fragile X Messenger Ribonucleoprotein). FMRP plays an important role in brain development. The lack of FMRP may disrupt signaling of the endocannabinoid system—a key network of neurotransmitters and receptors that modulate various functions, including synaptic activity. This dysregulation in neuronal signaling may contribute to FXS symptoms, such as autism-like behaviors (including social anxiety), cognitive impairment, intellectual disability, mood swings, attention deficiency, irritability, and increased risk for aggression.

It’s estimated that approximately 1 in 4,000 to 7,000 males and 1 in 8,000 to 11,000 females have FXS.

22q11.2 Deletion Syndrome

22q11.2 deletion syndrome (22q) is a disorder caused by a small missing piece of the 22nd chromosome. The deletion occurs near the middle of the chromosome at a location designated q11.2. It is considered a midline condition, with physical symptoms including characteristic palate abnormalities, heart defects, immune dysfunction, and esophageal/GI issues, as well as debilitating neuropsychiatric and behavioral symptoms, including anxiety, irritability, social withdrawal, ADHD, cognitive impairment, and autism spectrum disorder.

It is estimated that 22q occurs in 1 in 4,000 live births, suggesting that there are approximately 80,000 people living with 22q in the US, and there are currently no FDA-approved treatments for this disorder.