What is Sotos Syndrome?
Sotos syndrome is a rare multisystemic genetic disorder characterized by a typical facial appearance, overgrowth of the body in early life with macrocephaly, and mild to severe intellectual disability.
Sotos Syndrome is an autosomal dominant condition which means that if either one of the parents has Sotos, there is a fifty percent chance that each of their children will inherit the condition.
In around 90% of children with Sotos Syndrome the cause is a mutation in the NSD1 gene. This gene provides instructions for making a protein that is involved in normal growth and development. The protein affected cannot then function properly and normal growth is disrupted. It is not currently clear how the disruption causes the overgrowth and other complications and research is ongoing.
How is it Manifested?
The following characteristics are present in Sotos Syndrome:
- A long narrow face with a high forehead
- Flushed (reddened) cheeks
- A small pointed chin – large mandible
- Corners of the eyes point downwards with an abnormal increase between the eyes
- Large feet/hands- clumsiness and awkward gait
- Intellectual disability (Autism Spectrum Disorder, Mild Intellectual Disability)
- Behavioural issues (can include Attention Deficit Hyperactivity Disorder, phobias, tantrums, obsessions/compulsions, social development delays)
- Delays in speech/language – monotone voice, stutter, problems with sound production
- Delays in motor skill development – weak muscle tone (hypotonia)
Additional characteristics may include:
- Curvature of the spine (scoliosis)
- Heart or kidney defects
- Hearing loss
- Problems with vision
- Some infants with this disorder experience jaundice and poor feeding
- A small percentage may develop cancer in childhood
Who is affected?
Sotos Syndrome is reported to occur in 1 in 10,000 to 14,000 newborns.
A clinical diagnosis of Sotos Syndrome may be gained by the presentation of the typical symptoms:
- Characteristic facial appearance
- Learning disability
- Childhood overgrowth
- Increased head circumference
This suspected diagnosis can be confirmed through a genetic test to check changes in the NSD1 gene.
There is no specific course of treatment for Sotos Syndrome. Treatment is usually based on symptoms which have been identified. Sotos Syndrome is not a life-threatening disorder and individuals may have a normal life expectancy.
Sotos Syndrome Support Association of Canada
The Sotos Syndrome Support Association of Canada helps to support families by providing them with information by way of handbooks, pamphlets, Internet, public lectures, and discussions, and with emotional support by facilitating discussions with other parents who have been through similar experiences.
National Organization for Rare Disorders
NORD, along with its more than 300 patient organization members, is committed to the identification, treatment, and cure of rare disorders through programs of education, advocacy, research, and patient services.