Sotos Syndrome

What is Sotos syndrome?

It is an extremely rare genetic condition characterized by distinctive physical appearance, learning disabilities, and developmental delay. The Sotos syndrome symptoms vary depending on the age group. It is also known as Sotos Sequence and cerebral gigantism. ^{(3, 4, 9, 10)}

Sotos syndrome Pictures

Image 1: An image of a child with Sotos syndrome with prominently large head circumference and wide set eyes.
Picture Source: i.ytimg.com

 

Photo 2: An adult patient with Sotos syndrome.
Image Source: i.pinimg.com

Image 3: A group of people with Sotos syndrome.
Picture Source: sotossyndrome.org

Sotos Syndrome in Newborn

A newborn wit Sotos syndrome has a large head circumference. The average head circumference I 13.5 inches while newborn with Sotos syndrome’s head circumference is 4.5 inches. The body length is longer than the average and the birth weight is heavier than the usual birth weight of newborn. The forehead is abnormally large and round.

It has a distinct pinched at the temple area. The eyes are slightly slanted downward at the corners and wide set. The entire facial area looks narrow and long, which is further emphasized by the pointed jaw.

The upper and lower extremities are large. The newborn has a rag doll appearance because of low muscle tone. The newborn is usually put under the bili light because of neonatal jaundice. ^{(1, 3, 4, 5, 7)}

Sotos Syndrome in Infants and Toddlers

As the newborn progresses to infancy and toddler stage, the progression is very low. The patient cannot fully control his head and the feeding is still a problem.

Other clinical manifestations include poor muscle tone leading to delayed development of fine motor skills. In fact, there are instance when facial expressions are delayed. The size of the head grow rapidly, which can be extremely alarming. ^{(1, 3, 5, 7)}

Sotos Syndrome in young children

Children with Sotos syndrome have an extremely large skull (macrocrania) but the brain remains small. Although the skull is large, it appears high and narrow. The forehead is prominent, the eyes are wide-spaced and the nose and cheeks are rosy. The roof of the mouth is narrow and arched upward. The muscles have low tone, language development is delay, and you will notice a generalized developmental delay. ^{(1, 3, 4, 7)}

Sotos Syndrome in Adults

Adults with Sotos syndrome have normal weight and height, although they are usually taller than the average height. However, adults with Sotos syndrome are susceptible to tumor and cancer. There is also a possibility of motor skill and coordination problems. As with the intellectual development, adults with Sotos syndrome are within the normal range for intellect. ^{(1, 3, 4)}

How common is Sotos Syndrome?

In every 14,000 newborn, one case of Sotos syndrome is reported. The clinical features of Sotos syndrome can be mistaken for other health conditions. Many cases of Sotos syndrome are not properly diagnosed. ^{(3, 4, 5, 7)}

What causes Sotos syndrome?

The primary cause of sotos syndrome is NSD1 gene mutation. What is NSD1 gene? It is the one responsible in providing instructions for making a protein that works as histone methyltransferase, an enzyme that modifies histone (structural protein) that is attached to the DNA.

It is the one responsible in giving the chromosomes their shape. It also controls the activities of the genes responsible in the growth and development of human. What happens in Sotos syndrome is that the body prevents one copy of the gene from producing functional protein. This causes disruption of the gene’s normal activities. ^{(5, 7)}

Is Sotos syndrome hereditary?

Most cases of Sotos syndrome occur in people with no family history of the disease. As mentioned above, Sotos syndrome is caused by new mutation of the NSD1 gene. ^{(5, 7, 8)}

Sotos Syndrome Diagnosis

To accurately diagnose the condition of the patient, the doctor will first assess for the clinical manifestations of Sotos syndrome. The doctor will watch out for signs of excessive growth, craniofacial configuration, and developmental delay. About 80% of patients with Sotos syndrome have brain abnormalities such as hydrocephalus. ⁽⁸⁾

Additional test should be performed such as DNA studies by fluorescence in situ hybridization analysis (FISH) to detect microdelections. A DNA analysis is one of the best methods to identifying NSD1 gene mutation. In some instances, genetic testing for NFIX is needed. It is also possible to detect Sotos syndrome in an unborn child. A DNA analysis is obtained from fetal cells by chronic villus sampling and amniocentesis. This is most likely the option if one of the parents have Sotos syndrome. Although, most cases of Sotos syndrome have nothing to do with genetic history. ^{(2, 3, 4, 5, 7)}

Sotos Syndrome Treatment

Treatment for Sotos syndrome involves a multi-disciplinary approach. Ideally, the treatment is directed towards Sotos syndrome symptoms. To thoroughly address the overall condition of the patient, a team of specialist works hands in hand.

They include neurologist, geneticists, endocrinologist, surgeons, orthopaedics, physical therapist, ophthalmologist, and speech pathologist. Other health care professionals might be also needed, especially when it comes to creating a comprehensive plan for the patient. ^{(3, 4, 7)}

Patients with Sotos syndrome, especially children should have a regular check up to assess the overall growth and development, not only physically but intellectually. Ideally, the examination is done once a year. During the examination, the doctor will focus on blood pressure measurement, eye examination, examination of the back to watch out for any signs of bone-related disease such as scoliosis. Speech and language evaluation are also a significant part of the examination process. ^{(5, 7, 8, 9)}

The moment the condition is diagnosed, it is important to have a regular clinical evaluation. This is to detect the extent of developmental delay, intellectual disability, and psychomotor retardation. Early intervention plays a very important role in the overall development of the patient. Religious clinical intervention can help the patients reach their highest potential.

Treatment and management include the following:

1. Infant stimulation
2. Special social support
3. Special education
4. Speech therapy ⁽⁷⁾
5. Physical therapy
6. Occupational therapy
7. Adaptive physical education
8. Genetic counselling both for the patients and their families. ^{(3, 4)}

Prognosis

Sotos syndrome may sound like an alarming health condition, but people who have it can live a life of normal expectancy. Sotos syndrome is not a life-threatening condition, although some patients who have it may not be able to live a normal life primarily because of the physical abnormalities.

Most cases of Sotos syndrome improved once they reach the normal expected growth rate. As a matter of fact, even the developmental delay can improve once the patient reaches school age years. ^{(5, 6, 8)}

References:

1. https://www.healthline.com/health/sotos-syndrome#symptoms2
2. https://www.healthline.com/health/sotos-syndrome#diagnosis6
3. http://www.socialstyrelsen.se/rarediseases/sotossyndrome
4. http://sotossyndrome.org/sotos-syndrome
5. https://en.wikipedia.org/wiki/Sotos_syndrome
6. http://www.brainfacts.org/diseases-disorders/diseases-a-to-z-from-ninds/sotos-syndrome/
7. https://www.specialeducationalneeds.co.uk/sotos-syndrome.html
8. https://contact.org.uk/medical-information/conditions/s/sotos-syndrome/
9. http://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/sotos-syndrome
10. https://www.gemssforschools.org/conditions/sotos/default