Sotos syndrome: etiology, neurological effects, and symptom management

Sotos Syndrome is a disorder that is often misunderstood. The purpose of this discussion is to explain the etiology of the disorder, placing special emphasis on the neurological component of this syndrome. The research will also explore the other aspects of the brain that are affected, such as structures involved in memory. In addition the discussion will focus on the symptoms and the treatment associated with the disorder.

Sotos Syndrome

Sotos Syndrome also known as Cerebral Gigantism was first discovered by Dr. Juan Sotos (Sotos et al. 1964). According to the National Institutes of Health Sotos Syndrome is a genetic disorder that is rare but not difficult to diagnose. The ease with which the disorder is diagnosed has a great deal to do with the characteristics of the disorder. Typically children with the disease have excessive physical growth during the first 2 to 3 years of life (NINDS Sotos Syndrome Information Page). Children with the disorder are also larger at birth than an infant without the syndrome (NINDS Sotos Syndrome Information Page). In addition, children with the disease tend to have the following symptoms: a disportionately large and long head and a forehead that protrudes slightly, down-slanting eyes, abnormally big hands and feet, and a wide space between the eyes known as hypertelorism (NINDS Sotos Syndrome Information Page).

Furthermore, those with the syndrome often experience clumsiness or unusual aggressiveness. Some of those that suffer with the disorder are also often diagnosed with attention deficit disorder, and may have other behavioral problems. The syndrome may also produce seizures, phobias, obsessions, kidney problems, heart defects, and vision problems. Researchers have also found that people with the disorder often form tumors and are more susceptible to certain cancers.

The National Institutes of Health Further reports that Sotos syndrome does not usually result in death. The institute points out that many of the aforementioned abnormalities are resolved once the growth rate of the child returns to normal (this usually occurs after the third year) (NINDS Sotos Syndrome Information Page). However, some of the problems associated with the disorder continue into adulthood.

It is evident that Sotos Syndrome can be a complicated condition. It appears that it varies greatly from child to child and manifests itself with numerous symptoms. In some cases an individual with the syndrome is able to live a relatively normal life once their growth slows and they began to grow at a normal pace. On the other hand, some people with the disease have more severe symptoms that may include aggressiveness, heart ailments, mental retardation and even certain cancers. Although this is a rare disorder, researchers have searched and found the underlying cause of Sotos Syndrome. The next section of this discussion will focus on the cause of the disorder.

Causes

According to an article published by John Hopkins University Sotos syndrome is the result of a mutation in the NSD1 gene. More specifically the article explains that in patients with Sotos syndrome harboring a chromosomal translocation, Kurotaki et al. (2002) isolated the NSD1 (606681) gene from the 5q35 breakpoint. They identified 1 nonsense, 3 frameshift, and 20 submicroscopic deletion mutations of NSD1 among 42 sporadic cases of Sotos syndrome. The results indicated that haploinsufficiency of NSD1 is the major cause of Sotos syndrome (Sotos Syndrome)."

Although there is a great deal that has been discovered concerning the specific gene mutation, there is a great deal of information that is unknown. There is very little evidence that the disease is hereditary as it is extremely rare to see the disease in more than one person in a family. Because the disorder is so rare research is slow but it is occurring. Now that we have garnered a greater understanding of the cause of Sotos syndrome, let us focus on the Neurological components of the disorder.

Neurological Components

Sotos Syndrome is a Cephalic disorder. This type of disorder is congenital and is derivative of either abnormal development of the nervous system or damage to the developing nervous system as a result of trauma (NINDS Cephalic Disorders Information Page). The vast majority of these disorders occur as a result of a disturbance in the early stages of fetal development. (NINDS Cephalic Disorders Information Page). This type of disturbance or damage is a major cause of death or physical and/or mental disability in children and adults. In addition to trauma Cephalic conditions can occur as a result of hereditary or genetic factors or as a result of environmental factors that a present throughout pregnancy (NINDS Cephalic Disorders Information Page). As was mentioned previously in the discussion Sotos syndrome occurs as a result of a genetic defect -- other cephalic disorders arise when the cranial sutures join too early. More is known about some Cephalic disorders than others, but experts are certain that more information about these disorders can be derived from a greater understanding of the central nervous system (NINDS Cephalic Disorders Information Page).

Neurological components of Sotos syndrome vary from patient to patient and include hypotonia (Hglund, 2003). Hypotonia is defined as a decrease in muscle tone. There are many underlying causes of hypotonia, Sotos Syndrome and other disorders of the central nervous system are one of the causes (NINDS Hypotonia Information Page). Hypotonia is characterized by a limp or rag doll appearance in infants and those that suffer with this order often have little or no head control (NINDS Hypotonia Information Page). Other characteristics associated with hypotonia are problems with breathing, speech, mobility and posture (NINDS Hypotonia Information Page). People with the disorder may also experience tiredness, ligament and joint laxity, and reduced reflexes (NINDS Hypotonia Information Page). This neurological problem does not have an effect on intellect.

Neurological components of the disorder also include delay in motor and language development (Hglund, 2003). Both of which usually improve as the child gets older.

According to Finegan et al. (1994), it was once believed that Mental retardation was a universal attribute of people with Sotos syndrome. However, Psychological assessments that have occurred throughout the years have found that IQ scores of people with the disorder were often average. This was the case even when there were irregular patterns of cognitive abilities and academic success. Additionally, language delay has also been found (Hughes, 1990; Sotos et al., 1964). However, the nature and level of such impairment has not yet been explained in its entirety but is has been noted that individuals with the disorder often have difficulty as it relates to word finding.

Sotos Syndrome tends to affect the temporal lobe (which is the lateral part of the cerebral cortex) (Tanguay, 2002). The temporal lobe affects both memory and hearing. This is why people with the syndrome can sometime experience hearing loss and may have difficulty finding words.

It is apparent that Sotos Syndrome may also involve several neurological components that can greatly reduce an individual's ability to function as it relates to mobility and language delay. There is also a great deal of evidence suggesting psychiatric and behavioral components of the disorder which will be discussed in the next section in greater detail.

Treatment

Treatment for the syndrome is symptomatic and geared toward each patient. For instance a patient suffering from hypotonia may receive physical therapy to assist them in gain more control over bodily movements. Likewise an individual with Sotos syndrome that has been diagnosed with ADD may be treated with behavioral counseling and medications. Behavioral therapies may also be needed to combat aggressiveness, develop social skills, combat tantrums and some personality disorders that may be present. The mental retardation that can occur as a result of Sotos may be treated with learning therapies and through special education. Also language delay may be treated with speech therapy.

Individuals that develop tumors and cancer as a result of the disorder may be treated with surgery, radiation or chemotherapy. Likewise those with heart defects or kidney problems may need surgery or dialysis. Medical treatments may also be necessary as it relates to any skeletal malformations that may persist into adulthood as some researchers have reported that people with the syndrome can sometimes suffer from cervical complications that cause back pain and may affect their ability to walk properly. In such cases, surgery may also be necessary.

Although there is no standard treatment for Sotos syndrome because of the variability of the disorder, many of the individual symptoms of the disorder can be treated. However, treatment can become complex if the individual has multiple symptoms. Practitioners and parents must take extraordinary precautions to ensure the proper medications are prescribed and other types of therapies do not confuse the individual.

Discussion and Conclusion

The purpose of this discussion was to explain the etiology of the disorder, placing special emphasis on the neurological component of this syndrome. The research indicated that Sotos syndrome is caused by a mutation in the NSD1 gene. Hereditary factors have not yet been conformed because there are very few families with more than one person with the syndrome.

As it related to the neurological components of the disorder, the research indicates that Sotos Syndrome is a cephalic disorder or the central nervous system. The syndrome often results in hypotonia which affect mobility and muscle control. The research also indicates that the disorder affects the temporal lobe which in turn has an impact upon memory and hearing. In addition, the discussion focused on the symptoms and the treatment associated with the disorder. The research found a variety of symptoms associated with Sotos syndrome. The most obvious symptoms involve the physical characteristics of people with the disorder. Other symptoms include language delays, hearing loss, aggressiveness, and personality disorders. There appears to be no standard treatment for the disorder but many of the symptoms of the disease can be treated.

Overall, it appears that Sotos Syndrome is an uncommon disorder that has several symptoms that occur concurrently. As a result the syndrome may be quite difficult to treat. It is apparent that a great deal more research needs to take place as it relates to Sotos Syndrome. It seems that because it is a genetic disorder there must be more emphasis placed on isolating the gene so that potential parents know whether or not their child might develop the disease. Such advances are being made slowly; the slowness of the progress probably has a great deal to do with the rareness of the syndrome. There are many more diseases that have higher prevalence rates and therefore garner more attention from researchers and resources.