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Reviewed June 2006
What is Sotos syndrome?
Sotos syndrome is a disorder characterized by a distinctive facial appearance, overgrowth in childhood, and learning disabilities or delayed development. Characteristic facial features include a long, narrow face; a high forehead; flushed (reddened) cheeks; and a small, pointed chin. In addition, the outside corners of the eyes may point downward (down-slanting palpebral fissures). This facial appearance is most notable in early childhood. Affected infants and children tend to grow quickly; they are significantly taller than their siblings and peers and have an unusually large head. Adult height is usually in the normal range, however.
People with Sotos syndrome often have intellectual impairment, and most also have behavioral problems. Frequent behavioral issues include attention deficit hyperactivity disorder (ADHD), phobias, obsessions and compulsions, tantrums, and impulsive behaviors. Problems with speech and language are also common. Affected individuals often have problems with sound production, stuttering, and a monotone voice. Additionally, weak muscle tone (hypotonia) may delay other aspects of early development, particularly motor skills such as sitting and crawling.
Other signs and symptoms of Sotos syndrome can include an abnormal side-to-side curvature of the spine (scoliosis), seizures, heart or kidney defects, hearing loss, and problems with vision. Some infants with this disorder experience yellowing of the skin and whites of the eyes (jaundice) and poor feeding. A few people with Sotos syndrome have developed cancer, most often in childhood, but no single form of cancer has been associated with this condition. It remains uncertain whether Sotos syndrome increases the risk of specific types of cancer. If people with this disorder have any increased cancer risk, their risk is only slightly greater than that of the general population.
How common is Sotos syndrome?
Sotos syndrome is reported to occur in 1 in 10,000 to 14,000 newborns. Many cases of this disorder are not diagnosed, however, so the true incidence may be closer to 1 in 5,000.
What genes are related to Sotos syndrome?
Mutations in the NSD1 gene cause Sotos syndrome.
The NSD1 gene provides instructions for making a protein that is involved in normal growth and development. The function of this protein is unknown, however. In the Japanese population, the most common genetic change leading to Sotos syndrome deletes genetic material from the region of chromosome 5 containing the NSD1 gene. In other populations, small mutations within the NSD1 gene occur more frequently. Genetic changes involving the NSD1 gene prevent one copy of the gene from producing any functional protein. It is unclear how a reduced amount of this protein during development leads to learning disabilities, overgrowth, and the other features of Sotos syndrome.
Read more about the NSD1 gene.
How do people inherit Sotos syndrome?
About 95 percent of Sotos syndrome cases occur in people with no history of the disorder in their family. Most of these cases result from new mutations involving the NSD1 gene.
A few families have been described with more than one affected family member. These cases helped researchers determine that Sotos syndrome has an autosomal dominant pattern of inheritance. Autosomal dominant inheritance means one copy of the altered gene in each cell is sufficient to cause the disorder.
Where can I find information about diagnosis or management of Sotos syndrome?
These resources address the diagnosis or management of Sotos syndrome and may include treatment providers.
General information about the diagnosis and management of genetic conditions is available in the Handbook. Read more about genetic testing, particularly the difference between clinical tests and research tests.
To locate a healthcare provider, see How can I find a genetics professional in my area? in the Handbook.
Where can I find additional information about Sotos syndrome?
You may find the following resources about Sotos syndrome helpful. These materials are written for the general public.
You may also be interested in these resources, which are designed for healthcare professionals and researchers.
What other names do people use for Sotos syndrome?
What if I still have specific questions about Sotos syndrome?
Where can I find general information about genetic conditions?
The Handbook provides basic information about genetics in clear language.
These links provide additional genetics resources that may be useful.
What glossary definitions help with understanding Sotos syndrome?
ADHD ; attention deficit hyperactivity disorder ; autosomal ; autosomal dominant ; cancer ; cell ; chromosome ; contiguous ; deletion ; gene ; gigantism ; hyperactivity ; hypotonia ; incidence ; inheritance ; jaundice ; kidney ; motor ; muscle tone ; pattern of inheritance ; population ; protein ; scoliosis ; syndrome
You may find definitions for these and many other terms in the Genetics Home Reference Glossary.
See also Understanding Medical Terminology.
References (11 links)
The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.