The spasmodic upper-body squeeze: a characteristic behavior in Smith-Magenis syndrome

Dev Med Child Neurol. 1994 Jan;36(1):78-83. doi: 10.1111/j.1469-8749.1994.tb11770.x.


The authors have observed a hand- and arm-squeezing behavior that seems to be highly characteristic of Smith-Magenis syndrome (SMS). This behavior serves as a useful diagnostic marker for SMS, a disorder in which the physical phenotype is often subtle. The squeezing behavior appears to be part of a complex upper-body tic which is exacerbated by happiness, excitement or overstimulation. The tic most often manifests as a 'self-hug', and is frequently associated with facial grimacing. Fleeting arm- and hand-squeezing movements may be repeated hundreds of times over the course of a day, but they do not significantly interfere with other hand functions. The excitable self-hugging in people with SMS may be one of the more benign and appealing aspects of their behavioral phenotype.

Publication types

  • Case Reports

MeSH terms

  • Adolescent
  • Adult
  • Arm
  • Child
  • Chromosome Deletion*
  • Chromosomes, Human, Pair 17*
  • Female
  • Hand
  • Humans
  • Intellectual Disability / genetics
  • Intellectual Disability / physiopathology*
  • Male
  • Middle Aged
  • Muscular Diseases / genetics
  • Muscular Diseases / physiopathology*
  • Self-Injurious Behavior / genetics
  • Self-Injurious Behavior / physiopathology*
  • Spasm
  • Syndrome