Fragile X - Introduction

Fragile X Syndrome is the most common inherited form of mental impairment and the most common known cause of autism. According to the Centers for Disease Control, an estimated one in 4,000 males and one in 6,000 to 8,000 females have Fragile X.

Fragile X Syndrome is caused by a mutation of a single gene, the Fragile X mental retardation 1 (FMR1) gene, on the X chromosome. The FMR1 gene produces a protein needed for normal brain development. Individuals with Fragile X lack this protein and, as a result, exhibit a number of behavioral and physicals symptoms including¹:

• mental and developmental impairment to varying degrees
• attention deficit and hyperactivity
• autistic behaviors
• anxiety
• large physical attributes, particularly of the face
• seizures in 25% of the population

Fragile X typically impacts boys more severely than girls with 20% of boys also receiving a diagnosis of autism. Most boys with Fragile X have intellectual disabilities while only up to half of all girls with Fragile X have significant intellectual disability. Emotional and behavioral problems are common across both genders¹.

There is no cure for Fragile X at this time. A variety of medications and behavioral interventions are used in an attempt to address individual symptoms of the disease. Drugs currently used in developmental disorders primarily focus on treating specific symptoms such as anxiety, or improving and controlling behavior. While some of these compounds may improve function to a limited degree, the poor efficacy of drugs used to treat Fragile X results in a vast unmet medical need. There are currently no drugs approved by the U.S. Food and Drug Administration to enhance cognitive function of people with developmental disorders.

Seaside is developing new drug treatments to correct or improve the course of Fragile X Syndrome. We currently have two compounds in active development for Fragile X: STX209 and STX107.