Rett syndrome, occurring exclusively in females, is characterized by regression of motor milestones and language after 1 year of age, ataxic gait or fine tremors of hands,
sighing respiration with intermittent apneic spells, repetitive hand wringing movements and autistic behaviour.
Associated features include generalized tonic-clonic seizures, feeding problems, and poor weight gain. Endorphin level in CSF is elevated.
Treatment with anticonvulsants controls seizures and with naltrexone, an opiate- receptor agent, improves apnea and behaviour problems in a proportion of cases.