Copyright (c) 2007 Grace Riddell

SMS Defined

A SYNDROME is a specific pattern of physical, behavioural, and developmental

features which occur together in a person due to a single underlying cause.


Smith-Magenis Syndrome (SMS) is associated with a missing section (called a

deletion) of chromosome 17. The first group of children with this deletion

was described in the 1980’s by Ann Smith, a genetic counsellor and Dr. Ellen

Magenis, a physician and chromosome expert.


A variety of unusual physical and behavioural characteristics have been found

in people with SMS.


What is Smith-Magenis Syndrome (SMS)?

What are the Features of SMS?

An individual with SMS may have just a few or many of the features outlined

below. Some individuals with SMS may never show significant behaviour

problems, although some degree of self injury and sleep disturbance probably

occurs in most.


Despite their sometimes difficult behaviours, most children and adults with SMS

are very appealing and affectionate, and have much untapped potential.

Clinical Features:

developmental delay

learning disability

mental retardation

low muscle tone in infancy

feeding problems in infancy

short stature

flat facial features

prominent jaw in older children and adults

abnormalities of the palate, with or without cleft lip

down-turned mouth

unusually formed ears

chronic ear infections

hearing impairments

eye problems including: strabismus (squint), nearsightedness

short fingers and toes

heart defects and murmurs

urinary system problems

scoliosis (curvature of the spine)

unusual gait (walking pattern)

sleep problems (frequent awakenings)


head banging

hand biting

picking at skin, sores, nails

pulling off fingernails and toenails

explosive outbursts


destructive and aggressive behaviour


arm hugging / hand squeezing when excited


Information copied from the Smith-Magenis Syndrome Foundation