> Sotos Syndrome

• Symptoms & Characteristics
• Treatment
• How Common Is It?
• Genetics & Inheritance
• Genetic Testing
• Support & More Information
• Alternative Names

Last Reviewed June 2, 2009

Symptoms & Characteristics

Sotos syndrome is a genetic condition that affects the growth and development of various parts of the body. Common characteristics and symptoms may include:

• characteristic facial features (such as a long, narrow face; small, pointed chin; and flushed cheeks)

• overgrowth in childhood and infancy with unusually large head

• behavioral problems (such as ADHD, phobias, tantrums, obessiveness and impulsiveness)

• speech and language problems (such as a monotone voice, stuttering, etc.)

• low muscle tone (hypotonia)

• advanced bone age

• cranial MRI/CT scan abnormalities

• abnormal curving of spine (scoliosis)

• seizures

• hearing loss

• yellowing of skin and white of eyes (jaundice) in infancy

• vision problems

• heart abnormalities

• kidney abnormalities

People with Sotos syndrome also have an increased risk to develop tumors, such as sacrococcygeal teratomas and neuroblastomas; however, this risk is most likely only slightly higher than the general population.

Treatment

There is no cure for Sotos syndrome. Early diagnosis, routine surveillance and treatment can help to manage some of the symptoms and sometimes prevent related problems.

How Common Is It?

About 1 in 14,000 live births are affected with Sotos syndrome.

Genetics & Inheritance

Sotos syndrome is caused by mutations in or a deletion of the NSD1 gene on chromosome 5 at the location q35.

We all have two copies of the NSD1 gene - one from each parent. In Sotos syndrome, having a mutation in a single copy is sufficient to cause the disease. This is called autosomal dominant inheritance.

• An affected person has a 50% chance with each pregnancy to have an affected child.

• About 95% of affected people are the first one in their family to be affected. Their mutation is a result of a sporadic, new ("de novo") mutation.

Due to the wide range of symptoms, parents of an affected person may want to consider genetic testing and genetic evaluations for Sotos syndrome themselves. The benefits and limitations of such testing and evaluations should be discussed with a qualified health care professional.

• If both parents have negative genetic testing and normal evaluations, recurrence risk to have another affected child may still be increased over the general population, about 1%. This residual risk is based on two factors: (1) the theoretical risk of germline mosaicism in which some of a person's egg or sperm cells may have a disease causing mutation, while the rest of the cells in their body do not and, (2) the risk for a second "de novo" mutation to occur in the same family. To date, there have been no reported cases of Sotos syndrome caused by germline mosaicism.

There are other genetic conditions that have characteristics that overlap with Sotos syndrome. Some of these conditions include Weaver syndrome, Simpson-Golabi-Behmel syndrome and Beckwith-Wiedemann syndrome.

A genetic consultation with a trained genetic professional is important for a complete evaluation, accurate diagnosis, as well as discussion of the benefits and limitations of testing and recurrence risk.

Genetic Testing

Clinical genetic testing for Sotos syndrome may be available through an in person genetic consultation for people who are considered at risk. Use our find a genetic professional directory to locate a trained genetic professional in your area.

• A medical geneticist can also be found at the American College of Medical Genetics website.

• A genetic counselor can also be found at the National Society of Genetic Counselors website.

Support & More Information

More information can be found at:

• Genetics Home Reference

Support can be found at:

• Sotos Syndrome Support Association

Alternative Names

• Cerebral gigantism
• Sotos sequence
• Sotos' syndrome