The Fucosidose is one of the very rare storage diseases with a progressive and sometimes intermittent course due to a lack of activity alpha-L-fucosidase, which is classified to the oligosaccharidoses or Glykopreteinosen. A groundbreaking treatment method is not yet in sight, which is why treatment with an allogeneic bone marrow transplant has so far been considered the most advanced method.
What is fucosidosis?
According to ELECTRONICSENCYCLOPEDIA, Fucosidosis, also known by the synonym alpha-L-fucosidase deficiency, is an extremely rare autosomal recessive inherited lysomal storage disease from the group of oligosaccharidoses that occurs not only in humans but also in dogs. The prevalence is less than 1 in 1,000,000 and the inheritance is autosomal recessive.
Of the 100 cases known and described so far, around 20 are affected patients from southern Italy (Grotteria and Mammola in the Reggio Calabria area). In the southwest of the United States (Colorado and New Mexico), a further increase in this disease has been observed.
About 40 percent of the blood is related. The founder effect, which results in significantly lower genotypic and phenotypic variability in the offspring, explains the high prevalence within these populations.
The founder effect is called the “Founder Effect” and describes the genetically determined deviation of an isolated population or founder population. The starting point for this deviation is the small number of existing “alleles” of the individuals who are involved in their creation. Different selection conditions are therefore out of the question.
A distinction is made between two types with flowing transitions: Type 1 is considered to be clinically more serious and begins between the 3rd and 18th month of the affected patient. Type 2 with a less progressive course begins between the 12th and 24th month. Due to the lower progressivity (2), the life expectancy of type 2 patients is higher than that of patients with type 1 disease. Fucosidosis is a disease that progresses less rapidly and less rapidly. That is why there is also talk of the opposite of progression, the positive regression.
A third type is up for discussion in relation to patients in the Netherlands. The expression is less pronounced and the disease presents itself overall as a juvenile form without angiokeratomas. These are benign skin changes. These consist of wart-shaped hyperkeratoses combined with telangiectasias or angiomas.
The cause of a generalized storage of the fucose-containing glycolipids and oligosaccharides in all tissues is the lack of activity of the alpha-L-fucosidase. Responsible for this, in turn, are the nonsense or missense mutations on a gene coding for alpha-L-fucosidase, FUCA 1. This is located on chromosome 1 gene locus p34.
This enzyme catalyzes the breakdown of L-fucose and glycolipids as well as oligosaccharides. Both contain fructose. The substrate fucose is a hexose. However, since the enzyme activity is reduced, non-metabolized, i.e. non-metabolized, fucose or fucose-containing compounds accumulate in the cells of all tissues in the body. The result is damage to the cell and the affected organs.
In the affected people, a pseudogene of Fuca1 is on chromosome 2. The polymorphic (multiform) Fuca2 gene is on chromosome 6. The enzyme activity in the blood serum and in the fibroblasts is controlled by the gene product of Fuca 2. So far, 20 different mutations have been found to cause fucosidosis.
Symptoms, ailments & signs
The typical symptoms of frucosidosis include facial deformations, abnormal morphological head and face disproportions from the norm, but also skeletal malformations.
Severe mental retardation as well as seizures, enlargement of the liver (hepatomegalia), enlargement of the spleen (splenomegalia) and enlargement of the heart (cardiomegalia) were found. Furthermore, deafness can occur. Age-dependent angiokeratomas and dysostosis multiplex have also been observed.
Fucosidosis can be diagnosed with a chromatographic urinalysis. Determining the enzyme in amnion and trophoblast cells as precisely as possible in the laboratory is not that easy. The findings can be confirmed in the laboratory by determining the activity of the alpha-L-fucosidase in the leukocytes. A genetic test is only required sometimes.
Fucosidase usually causes various deformations in the face. These deformations can stress the patient both physically and mentally and reduce the quality of life enormously. Those affected suffer from severe psychological complaints and depression. The parents and relatives of the patient can also be affected by the psychological complaints.
This leads to seizures and retardation of the patient. The intelligence decreases and the patient is dependent on the help of other people in his everyday life. There is also an enlargement of the spleen and heart, which can be life-threatening for the person concerned. As a rule, the enlargement of the spleen caused by fucosidase leads to pain.
As the disease progresses, there is also a loss of hearing. Unfortunately, it is not possible to treat fucosidase. The symptoms can also only be treated to a very limited extent. The life expectancy of the patient decreases extremely due to the fucosidase, in most cases those affected can only reach the age of ten.
When should you go to the doctor?
Fucosidase is usually diagnosed before the affected child is born. At the latest at birth, the diagnosis can be made on the basis of the typical malformations. Parents should see a doctor if the discomfort worsens or any unusual symptoms develop. An emergency doctor should be called in the event of seizures and convulsions. Signs of enlargement of the organs also require a quick clarification by a specialist.
If serious complications arise, the child must be taken to hospital immediately. In the event of psychological complaints, a therapist should be consulted as soon as possible. This is recommended for both the affected child and the parents, as both parties usually suffer from the serious illness and its effects.
If adverse events occur in the course of the drug treatment, it is best to speak to the responsible doctor. The patient should also see a doctor if there are wound healing disorders, infections or other complications in the area of the operation after an operation.
Treatment & Therapy
So far only one therapy is known. The non-symptomatic bone marrow transplant. It is considered a treatment method with a curative approach. Around ten patients have been treated with this method so far.
A final assessment can therefore not yet be made. It was first tested on dogs. From a purely prognostic point of view, in contrast to earlier times, when they were seldom older than five years, patients can now reach the second decade of life.
Outlook & forecast
Fucosidosis is a serious disease that is progressive. The only treatment option so far, bone marrow transplantation, is fraught with many risks and has so far only been successfully carried out in a few patients. The prognosis is accordingly negative.
Typical symptoms such as mental damage and organ disorders usually cannot be treated effectively and ultimately lead to the death of the patient. Before that, the quality of life and wellbeing gradually decrease as a result of the complaints. In the further course serious complications occur, which not only limit the affected person extremely, but also greatly reduce life expectancy. Most sufferers die before the age of ten from the consequences of fucosidosis.
If the bone marrow transplant succeeds, further physical and mental complaints can be avoided under certain circumstances. The prerequisite for this is that treatment is started early and the patient is not severely disabled from birth. If these factors are present, the progression of fucosidosis can be stopped.
Congenital malformations and mental impairments can then be treated with surgery, physiotherapy and medication, among other things. Despite all the measures, the affected child can usually not lead a completely symptom-free life, as fucosidosis causes health problems even after a transplant. Therefore, the sick have to be treated medically for a lifetime.
So far, medical research has not succeeded in developing preventive measures. Because medical research does not yet have any further findings beyond the starting points, there are still no ways to counteract an outbreak of this disease with an assumed genetic predisposition.
In most cases, the options for follow-up care for a fucosidase are very limited. The person concerned is primarily dependent on the direct medical treatment of the disease by a doctor in order to avoid further complications and complaints. Self-healing cannot occur.
In order to prevent the disease from being passed on to your descendants, genetic counseling should also be carried out if you want to have children. The treatment itself is usually carried out by transplanting the bone marrow. There are usually no particular complications or other complaints, although the fucosidase can only be cured for a short time.
Unfortunately, a complete cure cannot be achieved, so that the life expectancy of the person affected is considerably limited and reduced by this disease. In many cases, when it comes to fucosidase, patients are also dependent on intensive care and support from their own family and friends. Above all, very loving and sensitive care of those affected has a positive effect on the further course of the disease. However, medical care by a psychologist may also be necessary in the event of psychological complaints.
You can do that yourself
Fucosidase is a serious disease from which most patients die before they are ten years old. The most important therapeutic measure is to relieve the symptoms.
This is achieved on the one hand through drug treatment, on the other hand through physiotherapy and rest. The affected child usually needs full-time care by a nursing staff and the parents. For the parents in particular, this represents a considerable physical and emotional burden. For this reason, an accompanying therapy is advisable, in which both the parents and the sick child can participate. If the course is severe, the parents and other relatives usually also need psychological support. Attending a self-help group and talking to other affected parents can also help to understand the disease.
The actual treatment can also be supported by a conscious diet. Furthermore, the child must be constantly monitored so that any seizures or other complications can be responded to quickly. If the internal organs are enlarged, different measures must be taken individually to alleviate the symptoms and to enable the child to continue living relatively pain-free.