Fragile X syndrome is a genetic condition inherited in an X-linked dominant pattern. It is usually due to the expansion of the CGG triplet repeat (trinucleotide repeat) within the Fragile X Mental Retardation 1 (FMR1) gene present on the X chromosome.
Diagnosis can be achieved through genetic testing. Testing for premutation carriers helps provide genetic counseling. Although there is no cure, early intervention is important as it increases the chances for patients to develop more skills. Interventions include behavioral therapy, special education, physical therapy, and speech therapy.
Medications may be necessary to manage mood problems, seizures, aggressive behavior, and more. Fragile X syndrome has been estimated to occur in 1.4 in 10,000 males and 0.9 in 10,000 females.
Symptom #1: Intellectual Disability
Those with fragile X syndrome can present with severe intellectual disabilities. Male patients with fragile X syndrome have an average intelligence quotient (IQ) of 40 if they have complete silencing of the FMR1 gene. Females tend to be less affected and usually present with an IQ of borderline learning difficulties or normal. These individuals face difficulties in executive function, short-term memory, working memory, visual spatial relationships, visual memory, and mathematics.
While the data on intellectual development among patients with fragile X syndrome is limited, there is some evidence that observed that their standardized IQ decreases with time due to slowed intellectual development. If autism is also present, there is greater deficit in IQ and language compared to those with only fragile X syndrome.