What is the Sanfilippo syndrome?
Sanfilippo syndrome is a disease of glycosaminoglycan metabolism that is inherited as an autosomal recessive trait. The disease is also called mucopolysaccharidosis type III and belongs to the group of mucopolysaccharidoses.
Depending on the gene defect in Sanfilippo syndrome, physicians distinguish between the four subtypes A to D. The Sanfilippo syndrome is very rare. Its frequency is 1: 60, 000. At the birth of the affected child, there are no obvious symptoms. Mucopolysaccharidosis manifests itself in the age of three to four years by very restless and aggressive behavior as well as delaying mental development.
From the second decade of life, in addition to the behavioral disorders of the patient spastic paralysis emerges, the intensity of which increases. However, unlike the other mucopolysaccharidoses, the organs, apart from the brain, are less affected. Thus, only a few abnormalities on the skeleton and the patients have usually a normal body growth.
The Sanfilippo syndrome was named after the American pediatrician and biologist Sylvester Sanfilippo. This described the disease for the first time in 1963.
Sanfilippo syndrome is caused by inherited defects of four different enzymes. These usually have the task of breaking down the glycosaminoglycan heparan sulfate. Affected are the enzymes SGHS (N-sulfoglucosamine sulfohydrolase), NAGLU (N-alpha-acetylglucosaminidase), HGSNAT (heparan-alpha-glucosaminide N-acetyltransferase) and GNS (N-acetylglucosamine-6-sulfatase).
The heparan sulfate is not degraded by the gene defect, so it stores in the lysosomes. These are the functional subunits of the cells, which are surrounded by their own membrane. Since there is an increasing overload of the nerve cells, this leads to disorders of the functioning of the lysosomes, which in turn causes complaints. The bones as well as the other organs are not affected as much by the disturbances as with other mucopolysaccharidoses because the heparan sulphate storage is lower.
Symptoms, complaints & signs
All four forms of Sanfilippo syndrome present a consistent picture of disability. Thus, the affected persons undergo significant changes in the physique as well as the psyche such as dementia or behavioral disorders. In addition, there may be other disorders such as hepatomegaly (liver enlargement).
Externally noticeable, Sanfilippo syndrome is characterized by enlargement of the tongue, full lips, a flat nose and the emergence of coarse facial features. The hair is very shaggy. In addition, the brows, which merge into each other, are dense and bushy. The affected children are becoming more behavior-sensitive and aggressive. Not infrequently, they tend to destructive behavior.
Since they lose their understanding of the language, they stop talking. Instead, they prefer gestures and facial expressions. Other possible signs include a higher susceptibility to infections, restrictions on joint mobility, inguinal and umbilical hernias and sleep problems. In some cases there is also optic nerve atrophy.
As the Sanfilippo syndrome progresses, signs of paralysis appear. The sick children move more and more insecure and finally lose their ability to walk completely. In addition, dysphagia and epileptic seizures are possible.
Diagnosis & disease course
If there is a suspicion of Sanfilippo syndrome, the treating physician determines the glycosaminoglycans in the urine. However, it is possible that their amount is only slightly increased in mucopolysaccharidosis type III. To obtain a reliable diagnosis, an electrophoresis is performed for this reason.
Their application clearly identifies the increased excretion of heparan sulfate. In addition, diagnosis can be made by determining the enzyme processes within the leukocytes (white blood cells) or in the fibroblasts. The course of Sanfilippo syndrome varies individually.
Depending on how severe the severity of the disease is, the death of the patient occurs in the second or third decade of life. In most cases, there is a significant loss of motor and mental abilities before. A meaningful contact with the disabled children is hardly possible. The death of the person affected is usually caused by pneumonia.
As a rule, sufferers in Sanfilippo syndrome suffer from a number of different disabilities. These have a very negative effect on the quality of life of the patient, so that in many cases they depend on the help of other people in their lives. Also, a dementia or various behavioral disorders can occur and thus significantly restrict the development of the person concerned.
Sometimes Sanfilippo syndrome causes enlargement of the liver and possibly pain. Due to the coarse facial features, the syndrome is also often associated with bullying or teasing so that patients may also suffer from depression or other mental disorders. Also, a higher susceptibility to infections or sleep problems often occur and lead to severe restrictions in everyday life.
Many sufferers also suffer from dysphagia and thus from complaints when taking food and liquids. Due to epileptic seizures, the life expectancy of the person concerned may be significantly reduced. The treatment can unfortunately only be symptomatic and depends on the symptoms. Special complications do not occur. Furthermore, the relatives or parents are often affected by the mental health problems.
When should you go to the doctor?
Sanfilippo syndrome must always be treated by a doctor. It can not come to a self-healing, with the complaints in most cases continue to worsen, if no treatment of the syndrome is initiated. A doctor should be consulted if the person is suffering from severe mental changes. This often leads to psychosis, depression or other disorders of the psyche. In most cases, these symptoms occur relatively suddenly and without any particular cause and significantly reduce the quality of life of the person concerned. It can also come to change the facial features.
If these symptoms occur, a doctor must be consulted in any case. Furthermore, sleep disorders or a very high susceptibility to infection may indicate the Sanfilippo syndrome and should also be examined by a physician. In some cases, sudden dysphagia also indicates this condition. When Sanfilippo syndrome primarily a general practitioner can be visited. The further treatment usually takes place by a specialist. Since the Sanfilippo syndrome is still relatively unexplored, no general prognosis can be given about the further course.
Therapy & Treatment
Treatment of the causes is not possible with Sanfilippo syndrome because it is a hereditary disease. Since 2014, there have been studies on enzyme replacement therapy for mucopolysaccharidosis IIIa. For the treatment of mucopolysaccharidosis II a special gene therapy is being tested. For certain forms of mucopolysaccharidosis, bone marrow transplantation is helpful in relieving the condition if it occurs before skeletal changes begin.
Unlike other mucopolysaccharidoses, there is still no approved enzyme replacement therapy for Sanfilippo syndrome. In order to treat the disease symptomatically, drugs are used to treat sleep disorders and hyperactivity. However, the effects of the medicines vary from child to child. So there is a risk that the preparations used lose their positive effect after a certain time again. Often it is therefore necessary to find out an individually suitable form of therapy for the patient.
If the affected children suffer from severe, aggressive or hyperactive behavior, protective measures must often be taken in their home environment to prevent injuries. In the case of dysphagia, switching to a pulpy diet is recommended. In some cases, the use of a gastric tube is required.
Sanfilippo syndrome is considered a hereditary disease. For this reason, there are no effective preventive measures against the disease.
The Sanfilippo syndrome is a hereditary disorder that allows only limited follow-up and prevention. Effective protection for patients is not available. Due to the congenital disorder of the children, follow-up care is mainly the responsibility of the parents. Depending on the behavior of the sick child through de-escalating measures or psychotherapy, these can alleviate the symptoms.
Doctors recommend avoiding everyday stress and hectic situations to ease the problems with the syndrome. Aftercare is also about reducing stress factors. Conflicts should be resolved as quickly as possible so that the child is not exposed to excessive stress. Creating rest periods for regeneration helps to regulate the level of stress.
For this purpose, the affected families should also talk to other people in the immediate vicinity. An enlightenment protects against misunderstandings and other problems. At the same time, the offspring must not be overstrained. That's why parents should not draw direct comparisons with other children, because they would put pressure on them. The motor disorders associated with the disease can be reduced by appropriate psychotherapy.
You can do that yourself
The disease is a congenital disorder. The measures of self-help are therefore to be carried out in particular by relatives and parents. It is up to you to develop strategies in good time so that deescalation can take place as quickly as possible in the event of the aggressive behavior of the child.
Stress and hectic everyday life should therefore be avoided. A well-regulated daily routine can help reduce potential stressors. Conflicts should be conducted constructively and clarifications from different opinions or views should be sought as soon as possible. The child needs sufficient rest periods so that regeneration can take place and recorded impressions can be processed as quickly as possible. In order to prevent adversity, people from the social environment should be informed and educated about the disease and its symptoms.
Due to delays in mental development, care must be taken to ensure that the younger generation is not overwhelmed during the development phase. Comparisons with peers and schoolmates of the same age are to be omitted. Also, pressure and disquiet should be avoided when learning new skills. Since it comes to disorders of the musculoskeletal system, help physiotherapeutic measures in the relief of complaints. These can be carried out independently. In addition, the child's sleep hygiene needs to be checked at regular intervals and optimized according to natural needs.