What CGG repeat size causes full Fragile X syndrome?

Full mutation ≥200 CGG repeats causes FXS in nearly all males; premutation 55-199 repeats causes FXTAS and FXPOI; normal <45 repeats; intermediate 45-54 repeats (unstable, can expand to premutation).

What intellectual disability level is typical in FXS males?

Severe-moderate intellectual disability (IQ 40-55) in most males; mild ID in some; females with full mutation have milder cognitive impact (IQ 70-85 mean) due to X-inactivation mosaicism.

What ASD features are characteristic of FXS?

Social anxiety and avoidance (rather than social indifference), tactile defensiveness, repetitive behaviors, hand flapping, poor eye contact; ASD criteria met in 30-50% of FXS males.

What medications help in Fragile X syndrome?

ADHD: stimulants (methylphenidate) and guanfacine; anxiety: SSRIs (sertraline/fluoxetine); irritability/aggression: atypical antipsychotics (aripiprazole, risperidone); seizures: standard AEDs; no disease-modifying drugs approved yet.

What is FXTAS and who does it affect?

Fragile X Tremor/Ataxia Syndrome affects male premutation carriers >50 years with progressive intention tremor, cerebellar ataxia, cognitive decline, and white matter lesions (MCP sign); ~40% of male premutation carriers over age 80.

Fragile X Syndrome Cognitive and Behavioral Assessment

Assesses Fragile X syndrome severity using CGG repeat expansion size, intellectual disability domain scoring, ASD features (ADOS-2 calibrated scores), ADHD severity, and anxiety management planning.

Use the full interactive calculator below, or

Related Calculators

Rett Severity Score

Medical Calculators

TSC Disease Burden

Medical Calculators

NF1 Disease Burden

Medical Calculators

Fragile X Syndrome Cognitive and Behavioral Assessment

Related Calculators

Frequently Asked Questions

What CGG repeat size causes full Fragile X syndrome?

What intellectual disability level is typical in FXS males?

What ASD features are characteristic of FXS?

What medications help in Fragile X syndrome?

What is FXTAS and who does it affect?