Smith-Magenis syndrome (SMS) is considered a developmental disability syndrome. SMS is characterized by distinctive facial features, developmental delay, intellectual impairment and distinct behaviors. Most individuals with SMS have a mild to moderate intellectual disability. The distinctive behavior includes an engaging and affectionate nature but may also include sleep disturbances, repetitive and ritualistic behaviors, and self-injurious behaviors. SMS is caused by a deletion of genetic material on part of chromosome 17. It is estimated that 1 in 15,000-25,000 children will be born with SMS.
This information was last revised in May 2020.