Muscle-eye-brain disease (MEB) belongs to the group of congenital muscular dystrophies which, in addition to severe functional disorders in the muscles, also have malformations in the eyes and brain. All diseases of this group are hereditary. All forms of muscle-eye-brain disease are incurable and lead to death in childhood or adolescence.

What is Muscle Eye Brain Disease?

In congenital myopathies, congenital muscular dystrophies are the diseases with the worst prognosis. These are characterized by severe malformations of muscles, eyes and brain. Muscle-eye-brain disease, a congenital muscular dystrophy, is closely related to the so-called Walker-Warburg syndrome. However, unlike Walker-Warburg syndrome, MEB is a bit milder.

In addition to the numerous muscular dystrophies, both diseases also show pathological changes in the eyes and brain. In Walker-Warburg syndrome, there is a defective cerebral system with patches of the brain (encephalocele), through which parts of the brain can escape to the outside. This is not the case with MEB, so encephalocele is the distinguishing feature of both diseases.

Because of this, life expectancy in Walker-Warburg syndrome is significantly lower than in muscle-eye-brain disease. Here it is only two years, while a patient with the muscle-eye-brain disease, depending on the course can be between 6 and 16 years old. Both diseases are also caused by mutations in the same genes.

Mainly six genes are responsible. The appearance of congenital muscular dystrophies is geographically very heterogeneous. Thus, the muscle-eye-brain disease is increasingly being observed in Finland. Overall, the estimates for all congenital muscular dystrophies are 1 in 20, 000 newborns.

causes

Causes of MEB are attributed to different gene defects in mainly six different genes. These are the genes for the enzymes POMT1, POMT2, POMGNT1, Fukutin (FKTN), FKRP or LARGE1. The respective encoded enzymes support the glycosylation of membrane proteins. POMT1 and POMT2 are protein O-mannosyltransferases.

They are responsible for the transfer of mannose to the membrane proteins of muscle, eye, and brain cells. This is where glycosidic binding of the mannose molecules to the functional side groups of the amino acids serine or threonine occurs within the protein chain. By linking the sugar residue to the protein chain, the properties of the protein change. The individual protein chains of the extracellular matrix and the cytoskeleton are more strongly cross-linked.

If this process is disrupted, it can lead to muscle-eye-brain disease. The other enzymes mentioned also each catalyze individual reaction steps in the glycosylation of proteins, which also contribute to the networking of extracellular matrix with the cytoskeleton. All forms of muscle-eye-brain disease are inherited as an autosomal recessive trait.

Persons with only one defective gene do not fall ill. However, if both parents each possess a mutated gene, their progeny has a 25% chance of developing MEB. This is the case when the child inherits the diseased gene from both parents.

Symptoms, complaints & signs

Muscle-eye-brain disease is characterized by a variety of serious symptoms and abnormalities of muscles, eyes and brain. The disease appears shortly after birth. The muscles have a low state of tension (tone). There is permanent muscle weakness.

The affected children have difficulty breastfeeding as they are very weak. Furthermore, they either have small eyeballs (microphthalmia), fissures in the eyes or greatly enlarged eyeballs. There are also the malformations of the retina and the development of glaucoma. It can also lead to blindness due to the malformations of the eyes.

The brain is also often malformed. The cerebral convolutions may be completely absent or unusually structured. The optic nerve is often poorly developed. Frequently an underdevelopment of the cerebellum is also observed. It comes to psychomotor restrictions, failure to thrive, convulsions and mental retardation. Sometimes a so-called hydrocephalus (hydrocephalus) occurs, which, however, is usually not very strong.

The mouth can be opened only to a limited extent, because the pine muscles contract. Muscle and eye weakness gets worse very quickly. This leads to a developmental delay of the child. The motor skills also worsen. There is more and more cramping. The disease is incurable and ends at the latest in adolescence deadly.

Diagnosis & disease course

To diagnose the MEB, an anamnesis of the family history is first performed. Here it is determined whether this disease has already occurred in the relationship. Genetic studies can determine which gene is responsible for the disease. Other examinations include brain ultrasound, eye inspection, and blood creatine kinase determination.

When should you go to the doctor?

In hereditary muscle-eye-brain disease, the first contact with the doctor is often given immediately after birth. The severity of the genetically caused damage is so serious that those affected usually do not have a long survival time. A maximum age of 16 years is achievable.

Why muscular-eye-brain disease is particularly prevalent in Finland is still a mystery. Ideally, it is known that both parents have appropriate genetic predispositions. In this case, the doctor's visit could serve as an abortifacient indication. Also a subsequent sterilization measure of the parents would be discussed.

Such gene dystrophies cause severe discomfort right at the beginning of life. They also leave noticeable damage to the brain and eyes. These consequential damages are usually noticed immediately, rarely a little later in a child's life. If the symptoms are not diagnosed right after birth, a doctor's visit will usually provide them within the next few months because of unusual weakness of the newborn.

The appearance of the newborn often already points to the muscle-eye-brain disease. A doctor's visit is therefore hard to avoid. All further visits to the doctor result in an attempt to alleviate the symptoms. More than symptomatic treatment, such as a ventilator or an artificial diet of children with the rarely occurring muscle-eye-brain disease, is currently not possible.

Treatment & Therapy

Unfortunately, there is no causal therapy for the MEB. This applies to all congenital muscular dystrophies. These diseases are very rare. Accordingly, there is little experience in their treatment. Only symptomatic treatments to improve quality of life and life extension are currently available.

In very severe cases, due to the muscle weakness, a partial feeding or ventilation is necessary. However, the most important measure is the best possible promotion of the child within the existing possibilities.

complications

In general, muscle-eye-brain disease causes various ailments and malformations that primarily occur in the patient's muscles, eyes and brain. Due to these malformations, the daily life of the person affected is clearly limited and there is a greatly reduced quality of life. Furthermore, the life expectancy is significantly reduced by this disease, so it usually comes in adulthood to the death of the patient.

As a result, mental health problems and depression occur, especially among relatives and parents. Those affected suffer from complete blindness and muscle weakness. As a result, the muscle-eye-brain disease in everyday life is severely restricted, so that in most cases patients are dependent on the help of other people.

Likewise, the symptoms also lead to mental retardation and, in general, to pronounced developmental delays. Likewise, those affected can suffer from severe cramps. A causal treatment of muscle-eye-brain disease is not possible. The complaints can be alleviated, however, so that everyday life for the patient is bearable. In the last stage of life, artificial nutrition and artificial respiration are necessary in most cases.

Outlook & Forecast

Muscle-eye-brain disease is one of the worst-case muscular dystrophies. The prospect of an improvement in the state of health is given only with early treatment. Regardless of the time of treatment, there is a risk of treatment failure. The result of failed therapy can be a re-infection. The nearsightedness of the affected children is progressing rapidly.

After only a few months of life, a clear deterioration in vision can be detected. Motor skills deteriorate significantly at the latest by the age of five. Accompanying this occur spasticity and contractures, which further worsen the prognosis. Life expectancy is greatly reduced. Depending on the course of the disease affected children reach the sixth to sixteenth year of life.

The quality of life decreases continuously. However, well-being can be improved by comprehensive symptomatic therapy, such as the use of analgesics and physiotherapy. The prognosis is made by the responsible specialist with regard to the detected symptoms and the constitution of the child. Overall, the forecast is bad. The rare disease also represents a great burden for the relatives of the child. Usually a therapeutic work-up is necessary. In general, the muscle-eye-brain disease is a serious condition that puts a lot of physical and mental strain on those affected.

prevention

MEB is a genetic disease. Therefore, there can be no preventive measures to prevent them. However, if cases of illness within the family or relationship are known, human genetic counseling can estimate the risks of transmission of the disease to offspring. If both parents are carriers of the mutant gene, the probability of MEB in the offspring is already 25 percent.

aftercare

In the case of muscle-eye-brain disease, aftercare usually proves to be relatively difficult, with the affected person in many cases having no special measures at their disposal. The person concerned should therefore consult a doctor at the first signs and symptoms of this disease, so that further complications or complaints can be prevented.

Because this is a genetic condition, complete healing usually can not occur. The person affected should therefore in the case of a desire to have a child carried out in any case a genetic examination and counseling to prevent a recurrence of the muscle-eye-brain disease.

The symptoms themselves can be alleviated by a few surgical procedures. The affected person should rest after such an intervention and protect his body. It is to be foreseen from efforts or from stressful and physical activities. Likewise, the help and care of one's own family is often very important.

Psychological support is also important to prevent depression and other mental health problems. Further follow-up care is not available to the patient in muscle-eye-brain disease, as the disease itself severely limits life expectancy.

You can do that yourself

Muscle-eye-brain disease leads to premature death as early as childhood or adolescents due to the severity of the disorders. The means and possibilities of the disease are minimal for the person concerned. There are no techniques or methods that can cure or achieve average life expectancy.

Due to the course of the disease, the focus is on improving the quality of life. The relatives and people from the social environment should inform themselves comprehensively about the illness and its consequences. A change of lifestyle takes place especially for the family members. Despite all the adversities and the poor prognosis, an optimistic and positive attitude to life helps to master the daily challenges. The leisure activities are to be organized according to the wishes and needs of all participants. Stress, strife and conflicts should be avoided if possible. In the decision-making process for the well-being of the patient unity and cohesion of the relatives are essential. They should act in the interest of the child and avoid selfish behavior patterns.

Since the illness represents a strong emotional burden, the use of psychological care for the relatives is advisable. An exchange in self-help groups can be perceived as strengthening, since tips and a mutual support is a central focus of the contact.

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