Three young children with Smith-Magenis syndrome: Their distinct, recognisable behavioural phenotype as the most important clinical symptoms

Three young children with Smith-Magenis syndrome: their distinct, recognisa ble behavioural phenotype as the most important clinical symptoms: We repor t on the development and behaviour of three young children with Smith-Magen is syndrome (SMS), del 17p11.2. The behaviour problems and the psychomotor delay in preschool children with SMS are often more striking than the dysmo rphic features and can serve as a useful clue to the diagnosis. We compare the behaviour with reported data. The behaviour problems in the three four year olds include very demanding behaviour, severe temper tantrums, hyperac tivity, aggressive behaviour, self injurious behaviour, sleeping problems a nd stereotypic behaviour. Head banging, hand, wrist or finger biting are pr esent. Onychotyllomania is not observed. Insertion of objects in the mouth as well as excessive nose picking is very frequent, although polyembolokoil omania is not present. The so called self hug when excited is present in on e child. The behaviour problems and psychomotor delay represent a major man agement problem for the parents.