Management of the behavioural manifestations of Hunter syndrome

This article reviews the behavioural manifestations of, and the strategies for managing, Hunter syndrome (mucopolysaccharidosis (MPS) type II), a rare X-linked lysosomal storage disorder caused by a deficiency of the enzyme iduronate-2-sulphatase. Hunter syndrome is generally considered to have two manifestations: an attenuated form and a severe form; in the latter, the person has pronounced cognitive decline. Infants with either phenotype usually appear normal at birth, but may show some somatic signs. Children with the severe phenotype show developmental delay and changes in behaviour patterns at about 18 months to 4 years of age. To varying degrees, patients with the severe form manifest behavioural disorders such as hyperactivity, aggression, impulsivity, anxiety and sleep disturbances. Medications, such as antipsychotics, benzodiazepines and anticonvulsants, have been tried with varying degrees of success. Behavioural management strategies may be a worthwhile approach, although published data are lacking. For sleep disturbances, behavioural modification plus melatonin or benzodiazepine may be effective treatments.