Communicative competence and behavioural phenotype in children with Smith-Magenis syndrome.

Smith-Magenis syndrome is characterized by a range of minor physical and facial abnormalities and is caused by a de novo deletion on chromosome 17. Most children function in the moderate to severe ranges of mental retardation. Results of a survey on adaptive skills, communicative competence and behavioural abnormalities in 20 children are reported. The findings suggest a strong desire to get in social contact and maintain conversations in spite of their limited cognitive processing. As a group, children with SMS are presenting with severe behavioural abnormalities, e.g. self-injury, extreme irritability, ritualistic behaviour. Behaviour problems are more severe than in other genetic syndrome groups as a comparison with Prader-Willi- and Fragile-X-syndrome children reveals. However, functional analysis suggests that it is not independent from situational variables. There is a strong need for behavioural intervention planning as part of family services.