Fragile X Syndrome

Fragile X is the commonest form of inherited learning disorder in males.

Epidemiology

• Prevalence 1 in 5,700 in males with a full FRAXA mutation
• Males affected
• Females are usually unaffected carriers.
• Some individuals carry smaller expansions.

Clinical presentation

• Full mutations in males
• Intelligence quotient is significantly reduced in males to approximately 41.
• Developmental delay with hypotonia is common
• Speech and language varies from no speech to mild . Individual rarely can speak fluently.
• Behaviour is characterised by overactivity, impulsiveness, reduced concentration and poor social interaction often punctuated by aggression. Autistic spectrum features are common.
• Many children have some degree of minor joint laxity.
• Macrocephaly
• Macro-orchidism
• Large ears