Fragile X is the commonest form of in-herited learning disorder in males.
- Prevalence 1 in 5700 in males with a full FRAXA mutation
- Males affected
- Females are usually unaffected carriers.
- Some individuals carry smaller expansions.
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.
- Large ears