Smith-Magenis Syndrome

Question 1

what is it?

Answer 1

Smith-Magenis syndrome is a genetic disorder that affects many parts of the body and many
areas of children’s development. It’s caused by missing genes on chromosome 17, or by changes
in the RAI1 gene on chromosome 17. This genetic change happens around the time of
conception

Question 2

prevalence

Answer 2

It occurs in 1
in 15 000-25 000 people

Question 3

key characteristics

Answer 3

facial features that include a broad, square face with deep-set eyes, full cheeks, a
prominent lower jaw, a flattened bridge of the nose, a downturned mouth,
 low muscle tone
 short stature
 developmental delay
 mild to moderate intellectual disability
 delayed speech and communication
 have a distinctive self-hug and a hand flick gesture
 strong desire to have adult attention or the attention of the person in authority
 may tend to put things in body orifices (ears, nose, anus, vagina etc.)
 may be aggressive & self-injurious. Often pick fingernails and toenails
 chronic sleep problems – Caused by inverted melatonin production - produce melatonin
through the day and not enough at night - so they are often awake at night and sleepy
through the day