Sotos syndrome, or cerebral gigantism, is a rare syndrome of birth defects that manifests itself as abnormalities in both physical and mental development. What are the causes and symptoms of Sotos syndrome? Is there a treatment for this rare disease?

The name " cerebral gigantism " refers to one of the most characteristic symptoms of this disease, that is the excessive size of the skull. In turn the eponym " Sotos syndrome " contains the name of the doctor who first described this disease entity. It is estimated that the frequency of Sotos syndrome is approximately 1: 15,000 live births. It was not until several years ago that a gene whose mutation is responsible for the formation of brain gigantism, i.e. the NSD1 gene, was discovered. In the vast majority of cases, mutations are completely random, so there is no increased risk of repeating Sotos syndrome in subsequent pregnancies.

Sotos syndrome: symptoms

More than 90 percent of patients have a three-symptom complex: characteristic facial dysmorphia, mental retardation, and tall stature. Facial dysmorphs in Sotos syndrome include, among others:

  • narrow, slender face (dolichocephaly)
  • tall, wide forehead that may resemble an inverted pear
  • high hairline
  • macrocephaly
  • hypertelorism, i.e. increased distance between the pupils
  • pointed, prominent chin
  • high palate
  • antimongoid arrangement of the eyelid slits (lowering the outer corners of the eye)
  • hair thinning at the temples and parietal areas
  • flushed cheeks

Apart from the characteristic features of appearance, among patients with Sotos syndrome more often than in the general population there is, among others: bone age advanced in relation to age, reluctance to suckle, muscle hypotonia, convulsions, posture defects (scoliosis, flat feet) and defects hearts.

The features of dysmorphia are most pronounced in young children, with age the facial features become softer and are no longer so pronounced.

Jaundice occurs in nearly 70 percent of newborns, but it has no permanent sequelae and resolves spontaneously over time. Sotos syndrome can also be accompanied by urinary tract defects, the most common of which is vesicoureteral reflux.

Children suffering from cerebral gigantism among their peers are distinguished by more advanced height and disproportionately large heads. With adolescence, these disproportions gradually disappear so that adults in these aspects differ from he althy people.

People with Sotos syndrome are also distinguished by various mental disorders. We can mention, among others, learning difficulties, concentration disorders of varying severity, hyperactivity or ADHD. Sometimes it also develops phobias, compulsive disorders or obsessions.

What other diseases can Sotos syndrome resemble?

Different dysmorphic features or syndromes are characteristic of different genetic diseases, however some elements may repeat in several units. Therefore, when suspecting cerebral gigantism, you should first exclude such diseases as:

  • Weaver syndrome - many features are in common with cerebral gigantism, but in this syndrome the head is rounder and the lower jaw is slightly more forward;
  • Bannayan-Riley-Ruvalcaba syndrome - features of dysmorphia may wrongly lead a doctor to suspect this disease, but after thorough examination, numerous vascular malformations, tendencies to the formation of polyps in the intestines and various skin lesions are detected;
  • Beckwith-Wiedemann syndrome - macrosomia is typical for this disease, however other deviations (such as tongue hypertrophy or organomegaly) successively exclude Sotos syndrome;
  • Simpson-Golabi-Behmel syndrome - in addition to excessive growth, also typical for cerebral gigantism, there are, among others, polydactyly, funnel-shaped chest, supernumerary nipples and other features of dysmorphia;
  • Fragile X syndrome - there are common features with Sotos syndrome, but numerous differences in the clinical picture usually do not cause problems in distinguishing these diseases;
  • familial macrocephaly - macrocephaly is an isolated defect here, and the diagnosis is usually made by excluding all other disease entities with this anomaly;
  • Marshall-Smith syndrome - exophthalmos, micrognation and phalangeal defects occur here;
  • Nevo syndrome - the clinical picture can sometimes be very similar to cerebral gigantism, so in some cases only a genetic test is decisive.

A total of a dozen or so cases have been described when the above-mentioned disease entities were suspected for a long time, but after thorough genetic research it turned outit was clear that these people had Sotos syndrome. This proves that you should always carry out diagnostics until the very end, because sometimes diseases that seem obvious turn out to be something completely different.

Sotos syndrome: diagnosis

Suspicion of Sotos syndrome, i.e. cerebral gigantism, should appear in the case of a child who shows the characteristic features of dysmorphia. Behavioral disorders are not detectable in the early stages of life, and therefore only complement the previous diagnosis.

Sometimes it may be helpful to extend the diagnosis to include imaging tests. There are no changes specific to Sotos syndrome in computed tomography or magnetic resonance imaging of the head, but there are some deviations that may help to diagnose or rule out the disease. In patients with cerebral gigantism, the most common lesion is the prominence of the lateral triangle and the lateral horns, as well as the widening of the ventricles. Various point systems that count specific dysmorphic features and summed up determine the likelihood of Sotos syndrome can also be helpful. Of course, all the methods mentioned so far are only intended to guide the clinician to the correct diagnosis, and the final "word" has the results of genetic testing that will detect specific mutations in the NSD1 gene.

Sotos syndrome: is there a treatment?

Sotos syndrome (cerebral gigantism) as a genetic disease is incurable. The patient can only be helped by treating accompanying diseases, and such a patient should be under comprehensive care by a team of specialists. Attention should be paid to possible postural defects, so as to implement treatment at the right time and h alt the progress of the disease. Psychological care is also important due to the possible coexistence of disorders related to this background, as well as special assistance in education. Detailed diagnostics for diseases to which Sotos's syndrome predisposes should be carried out and then regularly monitored.

Category:

Genetic diseases