What Is Sotos Syndrome?

Sotos syndrome is a rare genetic condition that causes excessive physical growth during the first two decades of life, starting from infancy and going into the teen years. Sotos is sometimes accompanied by autism, speech impairments, and intellectual, social, and motor delays.

While the condition does affect children in the school years and may continue to cause problems into adulthood, it is not life threatening. Most people with Sotos have normal life expectancies.

According to the U.S. National Library of Medicine, Sotos syndrome is believed to occur in one out of every 10,000 to 14,000 births. Researchers speculate the true incidence may be closer to one in every 5,000 births, as other conditions cause similar symptoms and misdiagnoses are possible.

Sotos Syndrome Symptoms

Sotos syndrome is characterized by overgrowth, especially in the bones. Affected persons have facial abnormalities that are especially significant in childhood. This includes having a head that is longer and wider than typical and a pointed chin.

Affected infants and children with Sotos grow quicker than other children their age. They will be taller than their siblings and peers.

Additional physical characteristics and symptoms may include:

• Large hands and feet
• High forehead
• Weak muscle tone
• Flushed cheeks
• Down-slanting eyes and a large distance between the eyes
• Awkward gait (walk)
• Scoliosis, a sideways curve of the spine
• Seizures, which result from abnormal brain activity
• Hearing loss
• Vision problems
• Premature teeth eruption
• Kidney problems, including hypoplastic kidneys and hydronephrosis
• Heart problems, including patent ductus arteriosus (PDA) and atrial septal defect (ASD)

Individuals may have intellectual impairment and behavioral problems, including:

• Attention-deficit hyperactivity disorder (ADHD)
• Obsessive-compulsive disorder (OCD)
• Impulsive control behaviors
• Phobias
• Aggressiveness and irritability

Developmental and intellectual problems in children may include:

• Speech and language problems, including stuttering
• Learning disabilities
• Clumsiness
• Motor skill problems

Sotos in Adulthood

Adult height and weight will stabilize and be somewhat normal, although there is one case of a 21-year-old man with Sotos who reached 7 feet, 8 inches tall and around 500 pounds.

Many adults with this condition will have normal intellect. However, any childhood intellectual disability will remain. Adults with Sotos will continue to have coordination and motor skill issues.

Causes

Sotos syndrome is a genetic disorder caused by a mutated NSD1 gene. According to the Genetic and Rare Diseases Information Center, 95% of Sotos cases are not inherited. However, the chance of a parent with Sotos passing the condition on is 50%.

There are no other known risk factors or causes of Sotos syndrome. Furthermore, researchers don’t know what causes the genetic mutation or how to prevent it.

Diagnosis

A Sotos syndrome diagnosis is made early in life, either in infancy or in the first few years of life. Newborn testing does not include testing for Sotos, but doctors will test for it when symptoms are noticed. It may take months or years for testing to occur and for symptoms to be pronounced.

Testing for Sotos starts with a physical exam and medical history, including a review of symptoms.

X-rays, CT scans, and MRIs can help with diagnosis and in ruling out other problems. Advanced bone age is commonly seen. Brain imaging shows dilated ventricles and increased cerebrospinal fluid (CSF).

Genetic testing may also be done to check for mutations in the NSD1 gene.

Many children with Sotos may also receive a diagnosis of autism. Autism is a developmental disorder affecting communication and behavior. It is generally managed with a variety of therapies, including behavioral and speech therapies, as needed.

Treatment

There is no cure for Sotos syndrome, nor is there one specific treatment for it. Treatment usually involves managing symptoms and correcting problems that can be corrected.

This may include:

• Speech therapy
• Occupational therapy
• Behavioral therapy
• Medications to manage ADHD
• Counseling
• Hearing aids to correct hearing loss
• Glasses to manage vision problems

Other medical conditions will also be treated, as needed.

A Word From Verywell

Sotos syndrome is a genetic disorder caused by a mutation of the NSD1 gene. The two main symptoms of Sotos syndrome are overgrowth and intellectual disability. It is often diagnosed in infancy or early childhood.

Once growth stops, adults with Sotos can maintain normal height and weight, and even intellect. Many adults with Sotos can lead long and fulfilling lives.