Sotos syndrome: symptoms, causes and treatment

Children with a bone age 2, 3 or even 4 years older than their chronological age, large hands and feet, sucking problems and some problems in their cognitive, social and motor development.

These are the main characteristics of Sotos syndrome, a medical condition of genetic origin which is quite common in the population despite the fact that it is not well known.

People who suffer from it end up developing more or less normally, although at the wrong time. Next we will discover more about this strange but, at the same time, frequent syndrome.

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What is Sotos syndrome?

Sotos syndrome is a medical condition of genetic origin that is characterized by excessive intrauterine or postnatal growth, accompanied by delayed motor, cognitive, and social development. Children with this syndrome are significantly taller than expected for their age, although they weigh accordingly to their height. In addition, newborns show excessive growth in the bones, hands and feet, and some characteristic facial features.

Unlike many genetic diseases, Sotos syndrome may not be evident at birth, taking months or even years to be properly diagnosed. As they approach adolescence, people who suffer from it are approaching a development closer to adulthood. normality, and in adulthood they may have an intellectual, behavioral and motor capacity appropriate to their environment social.

This syndrome It receives its name from Dr. Juan Sotos in 1964, a specialist in pediatric endocrinology. who described 5 children with learning disabilities, overgrowth, and characteristic appearance, calling it brain gigantism for the first time. However, not all the credit is attributable to Sotos, since Dr. Bernard Schelensinger described in 1931 to a patient whose symptoms were consistent with this syndrome, being the first known description of the syndrome.

Apparently, It is one of the most common overgrowth syndromes.. Although the true incidence has not been able to be assessed, it is estimated that between 1 in 10,000 or 50,000 live births have this syndrome, although the safest estimate is 1 in 14,000 births. It is probably the second most common overgrowth syndrome, after Beckwith Wiedemann syndrome.

Causes

All the exact causes of the syndrome are unknown, but it is clear that its origin is genetic, being autosomal dominant inheritance.

In 2002 it was discovered that on chromosome 5, mutations and deletions in its NSD1 gene could be behind Sotos syndrome (5q35 deletion). This gene is a histone methyltransferase involved in transcriptional regulation. About at least 75% of Sotos cases present this gene alteration.

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Characteristics of the syndrome

There are several characteristics that define this syndrome. The main symptom is fairly rapid growth during the first 5 years of life, in addition to having an advanced bone age. The children present a size and weight according to children 2 or 3 years older than them. At the age of 10, children with Sotos syndrome have a height typical of adolescents of 14 or 15 years, reaching the height of an adult much earlier than expected.

At birth you can see the presence of a highly arched palate, which causes the baby to have difficulties sucking and this leads to feeding problems, which can lead to jaundice. Its head is usually large, presenting macrocephaly, prominent forehead and wattles. They can also present dolichocephaly, that is, an elongated skull. This is due to the exaggerated increase in brain tissue, which causes retention of cerebrospinal fluid in the ventricles.

The forehead is domed, and they may present ocular hypertelorism, that is, the eyes are very separated.. There are palpebral fissures, that is, folds are formed by the downward inclination of the eyelids. The nasal bridge is flat, and the nose is anteverted. The cheeks and nose are flushed. The ears are perky and large, and the hairline is retroactive. Teeth develop prematurely, commensurate with their overgrowth.

They have disproportionately large hands and feet compared to the rest of the body, as well as having flat or collapsed feet. Your spine may tend to suffer deviations that, if chronic, will lead to scoliosis. All this is accompanied by muscular hypotonia, leading to motor delays and difficulty in movement. This also affects the face, since the tone of the facial muscles is low, causing prolonged drooling and they have to breathe through their mouths.

People with Sotos syndrome often present pictures of restlessness, hyperactivity and aggressiveness. In addition, intellectual disability can occur, although in a very variable way, aggravated by difficulties in the development of language. It should be said that language problems are due to the arched palate. Be that as it may, all these psychological characteristics make it difficult to integrate into different social environments.

Although the person may have problems during the first years of his life, the differences with respect to people without the syndrome begin to reduce in pre-adolescence. Muscle tone improves, making swallowing and speaking easier, and motor, cognitive, and social delays are reduced to the point of disappearing in many cases. That is why Sotos syndrome is considered by many to be simply a disturbance of developmental timing rather than a type of disability.

There are other traits that are also related to the syndrome, although they are less common. Among them are dysfunctional behavior patterns, phobias, obsessions, aggressiveness and adherence to routine. There are cases of children who present a high memory capacity and autistic behaviors, similar to Asperger's, as well as hyperactivity.

There seems to be a greater sensitivity to ear infections, respiratory problems such as asthma and allergies, as well as a greater risk of presenting tumors and seizures. There may be delayed sphincter control and cardiac abnormalities, directly related to muscle hypotonia.

Diagnosis

A fundamental aspect in the diagnosis of Sotos syndrome is to make sure that an adequate differential diagnosis is made, making sure that it is not related to others with similar characteristics. Among the diseases that can be confused with this syndrome we have as the fragile X syndrome, Weaver syndrome and Marfan syndrome, very similar to de Sotos syndrome but with more serious long-term consequences.

There are no specific tests for its diagnosis, which is mainly based on the recognition of physical features. However, different tests can be used to confirm the diagnosis. X-rays of the hand and wrist can be used to determine the maturity of the bones, detecting an advance of 2 or 3 years. Computerized axial tomography (CT) of the brain allows us to see if the ventricles are abnormally large.

Other tests, to rule out other possible causes of the clinical picture, are hormonal measurements and performing a karyotype, that is, a study of the patient's chromosomes. If the alteration in the NSD1 gene is detected, it can be ensured that it is a case of Sotos syndrome. At present it is not possible to make a diagnosis before birth.

Treatment

The treatment of Sotos syndrome is aimed at make the social, cognitive and motor development of the child who suffers from it as close to normal as possible. Thus, many techniques are applied to help the child develop in a way relatively normal, such as early stimulation, occupational therapy, physical therapy, speech therapy, and physical education. In a structured environment, the child is able to practice necessary skills without too many distractions.

As we have mentioned, these children can present behavioral problems, such as restlessness, aggressiveness and hyperactivity. This hinders their ability to concentrate and hinders learning, for this reason, and given that the origin of these symptoms is biological, the pharmacological route is usually used. Among the most used drugs we have methylphenidate hydrochloride, which is also used in ADHD.

Bibliographic references:

• Lapunzina P (2010). Sotos syndrome. Diagnostic and therapeutic protocols in pediatrics; 1:71-9.