If you were to ask passers-by in a city what MERRF is, many of them would not be able to answer that question. MERRF is one of approximately 600 metabolic diseases (known in the medical world), which is also quite rare. A metabolic disease is always hereditary and present at birth. This is no different with MERRF, although in most cases the first symptoms only reveal themselves (much) later. Both boys and girls can get it.
What is MERRF
MERRF is the abbreviation of Myoclonus Epilepsy with Ragged Red Fibers. Myoclonus Epilepsy is a form of epilepsy that is often seen in children with MERRF. In this form, short-term shocks occur in the body, although in MERRF sufferers you also see the so-called Grand mal, in which a person jerks violently and also loses consciousness.
Ragged Red Fibers refers to certain inclusions that can only be found in the muscles of people with MERRF.
MERRF is caused by an error in the hereditary material. This error is not on the chromosomes, but is present on the mitochondria. Mitochondria are the bean-shaped organs in a cell that provide it with energy. Due to this error in the hereditary material, certain proteins are not produced. Important proteins that provide the cell with its much-needed energy. Because these proteins are missing, the mitochondria cannot provide their host cells with the energy needed for the body to function properly. These cells will not be able to do their job properly, which can cause a whole range of complaints, ranging from muscle weakness or poor vision to epilepsy and poorly functioning heart muscle. Sometimes the mitochondria are damaged to such an extent that cells even die, with all the consequences that entails.
The severity of the disease course depends on how many mitochondria are affected. If there are proportionally more healthy mitochondria than affected ones, the disease will progress less grimly than if this is the other way around.
Inheritance
Since the mother’s egg is the only supplier of mitochondria at fertilization, MERRF is always inherited through the mother. If the mother is a carrier or has the disease herself, all her children can inherit it from her. However, the passing on of mitochondria occurs completely randomly; if the mother has 25% affected mitochondria, her child can inherit them all. It may also be that it is lucky and only receives healthy mitochondria from its mother, so it does not get sick. The following also applies: the fewer incorrect cells are passed on, the milder the disease will progress.
A whole range of complaints
As stated above, the number and severity of MERRF symptoms can vary from person to person. After all, this is related to the number of mitochondria that are affected. In the first years of life, there seems to be little wrong with most children. They develop normally, sit, crawl, walk and babble at the usual time. The only thing that may be noticeable is their short length. Children with MERRF are also usually smaller than average before the symptoms start. This often only happens around the age of six. Sometimes this happens (much) later. The following also applies: The later the complaints start, the higher the life expectancy.
What are the complaints that someone with MERRF can develop:
Epileptic seizures
One of the first symptoms of MERRF is often the occurrence of epileptic seizures. This epilepsy can vary in severity. Some patients can lead a reasonably seizure-free life with the help of anti-epileptic drugs, while there are also stories of MERRF patients whose epilepsy seizures increased in number and frequency over the course of their lives to such an extent that it was the ultimate cause of death.
Muscle weakness
Because muscles also need proteins to function properly and these proteins are often missing or damaged in people with MERRF, this also affects the muscle strength of these people. Their muscles often tire more quickly and are less strong. This is most noticeable in the muscles around the pelvis and shoulders. For example, many people with MERRF walk with a bit of a waddle and have difficulty reaching things that are above their heads.
Since the heart is also a muscle, it can also be affected and heart problems can arise. The development of spasticity is also a possibility. Arms and legs can move less well due to muscle weakness and become cramped. Another problem resulting from muscle weakness is that the eyelids can droop when someone with MERRF is tired. This can cause such a person to suffer from double vision.
Hearing impairment
MERRF is a progressive disease. During the course of the disease process, hearing can deteriorate, even resulting in deafness.
Visual impairment
Someone with MERRF often also has problems with vision, because the optic nerve becomes increasingly thinner during the course of the disease. This process is gradual and can lead to damage to the retina, which in the worst case can even lead to blindness. In the beginning, someone with MERRF is often only night blind, later they also have problems seeing during the day and because in some cases they can no longer move their eyes properly in all directions, a patient can suffer from double vision.
Problems with the nerves
In three out of five people with MERRF, the signals that need to go from the brain to the muscles via the nerves are not properly transmitted. This causes, among other things, uncoordinated movements or that they cannot properly perform planned movements (such as grabbing a cup from the cupboard).
Developmental decline
Many children with MERRF, who initially appeared to develop normally, fall further and further behind their peers during the course of the disease process. It becomes increasingly difficult to learn new things and sometimes they even forget things they have learned before. Epileptic seizures, especially if there are many, can damage the brain and cause children with MERRF to have difficulty concentrating and mastering new learning material. Young people with MERFF gradually have more and more problems with moving, walking, talking and become increasingly visually and/or hearing impaired.
Other complaints such as diabetes and fatty lumps
By means of which studies can MERRF be determined?
The disease MERRF is quite easy to diagnose because of the clearly visible abnormalities after examination. The following tests can be performed to arrive at a diagnosis:
- Taking a history – based on the story of the patient and his parents, an image of the disease can be obtained.
- blood test – abnormalities in the mitochondria can be found in the blood. For example, blood from MERRF patients contains more lactic acid than usual.
- MRI scan of the brain. This shows, among other things, that calcium deposits in certain parts of the brain, that they become smaller and that the cerebral cortex looks different.
- An epidural puncture can be used to examine the fluid that flows around the brain and spinal cord for the presence of lactate (lactic acid). In the MERRF patient this percentage will be higher than usual.
- By doing a muscle biopsy on the patient, the so-called Ragged Red Fibers can be found in the muscles.
- EEG to determine epileptic activities in the brain. In people with MERFF, the background brain pattern is also slower than in people without this disease
- ECG: Indications of cardiac arrhythmias can be found on an ECG.
Genetic research can also be done. After all, MERRF is hereditary and often it runs in the family and there are others within the family or extended family who suffer from it.
What are the treatment options for MERRF?
Unfortunately, MERRF cannot be cured. The more mitochondria are affected, the shorter the life expectancy. When there are few diseased cells and the first symptoms of the disease manifest themselves later in life, the chances of living to a reasonable age are much greater. In adulthood, this patient often has fragile health. Heart problems or epilepsy can occur. Someone may also suffer from stiff muscles, hearing loss, visual impairment or other discomforts. In short: manifestations of the complaints associated with MERRF, although the course will be milder than in people who have the disease to a more serious extent.
Their life expectancy has been greatly shortened. For example, patients with the worse form of MERRF die due to heart problems or after complications from continuous, unresponsive seizures.
The treatment consists of limiting the consequences of MERRF as much as possible. To this end, a child can be treated by various specialists, who, for example, monitor the heart, ears and eyes. Medicines can be prescribed to combat epileptic seizures. Furthermore, coenzyme Q10 appears to have a beneficial effect, although no hard evidence can be provided for this.
Finally, it is very important for a MERRF patient to pay attention to his diet. Eating healthy and responsibly, which may prevent diabetes. This is often done under the supervision of a dietician. Eating certain proteins may also have a beneficial effect on the patient’s overall health.
