Fukuyama muscular dystrophy is a rare congenital muscle wasting disease that occurs mainly in Japan. The disease is caused by the mutated so-called FCMD gene, which is responsible for coding the protein fukutin. The disease is associated with severe mental and motor development disorders and shows a progressive course, so that the average life expectancy is only around ten years.
What is Fukuyama muscular dystrophy?
Fukuyama muscular dystrophy (FCMD) is a genetic congenital muscle wasting disease with symptoms present at birth. The rare FCMD is inherited in an autosomal recessive manner. Their main distribution area is Japan. See electronicsmatter for Leaky Gut Syndrome Definition.
The disease is associated with severe intellectual and motor developmental disabilities and is causally related to an incorrectly encoded transmembrane protein called fukutin. Fukutin is synthesized in major amounts in the central nervous system, pancreas, heart, and skeletal muscle.
Due to the central and systemic importance of the protein fukutin in cell metabolism, primarily in the Golgi membrane of the cells, serious systemic symptoms occur. As a rule, the disease is accompanied during the first five years by a greatly increased CK (creatine kinase) value, which can reach ten to fifty times the normal concentration.
Causes
The direct cause of FCMD is a functional restriction or a complete loss of function of the structural protein fukutin. It is a so-called single-pass transmembrane protein that performs central tasks in the membrane of the Golgi organelles. The complex tasks of the Golgi apparatus of a cell include the formation and storage of secretory vesicles and intracellular lysosomes.
The functional restriction of the fukutin is due to a genetic defect that leads to an incorrect coding of the fukutin. This is one of several known mutations in the fukutin gene at gene locus 9q31-q33. The process that leads to the defective coding of fukutin due to the detectable gene mutation is not (yet) fully understood.
Symptoms, Ailments & Signs
The first externally recognizable symptoms of congenial muscular dystrophy type Fukuyama usually appear in infancy immediately after birth. Babies typically have weak muscle tone, which is reflected in general muscle weakness. The sucking and crying reflexes of the affected newborns are weak and the babies are generally limp.
Contractures, restricted movement of the hips, knees and the interphalangeal joints are common and typical. In the further development, there are typical myopathic facial features, which can be recognized by a weak and “flabby” facial expression.
In many cases, the retina is also affected in the form of retinal dysplasia of varying severity and corresponding visual impairment. So-called pseudohypertrophies on the calves and forearms, which are caused by an increase in interstitial connective tissue, are also symptomatic at a later stage.
However, symptoms of extremely slow mental development, which are based on an abnormal development in the system of important structures of the central nervous system (lissencephaly), are particularly serious.
Diagnosis & course of disease
Symptoms occurring immediately after birth that raise suspicion of FCMD should be evaluated with electromyography or muscle biopsy and neurological tests. Above all, other diseases such as Duchenne muscular dystrophy and Becker muscular dystrophy as well as muscular dystrophies that are associated with lissencephaly like FCMD must be ruled out by differential diagnosis.
Molecular genetic testing of the fukutin gene can provide ultimate certainty. If cases of FCMD are already known within the family of one of the parents, the molecular genetic examination can also be carried out prenatally – without considering possible ethical aspects. The course of the disease is variable, but always serious.
The mental and motor development disorders that can be identified early are so serious that only a few affected children learn to speak and walk. Epileptic seizures occur in more than half of the patients. In the further course – at the latest from the age of ten – swallowing and eating disorders as well as heart problems appear, which are ultimately associated with a very poor prognosis.
Complications
As a rule, the muscular dystrophy type Fukuyama leads to various restrictions and complaints immediately after birth. Most of those affected primarily suffer from severe muscle weakness. Normal activities are no longer possible for those affected, which leads to significant delays and restrictions in development, especially in children. There are also mental and motor problems.
Those affected appear clumsy and often suffer from restricted mobility. There are also unusual facial features, with children in particular suffering from this complaint through bullying or teasing. It is not uncommon for Fukuyama muscular dystrophy to also lead to poor eyesight or blurred vision.
The quality of life of those affected is significantly reduced by this disease. Due to the disturbed mental development, those affected are often dependent on the help of other people in their everyday lives. A causal treatment of Fukuyama muscular dystrophy is not possible, so that usually only the complaints and symptoms are treated.
There are no complications. In acute emergencies, surgical interventions are also necessary to prevent cardiac arrest due to breathing difficulties.
When should you go to the doctor?
Fukuyama muscular dystrophy is usually diagnosed immediately after birth. The doctor treating you can identify the disease based on the muscle weakness and other typical symptoms and will promptly initiate a detailed diagnosis. Parents of affected children must consult the doctor closely so that medication and physiotherapy can be regularly adapted to the rapidly changing symptoms. Depending on the symptoms, other specialists must be consulted, for example for the typically occurring visual impairment.
If epileptic seizures, swallowing and eating disorders or heart problems occur during the course of the disease, the nearest hospital must be visited immediately. Usually, various complaints occur directly after birth, which necessitate an inpatient stay in the hospital. In the case of mild Fukuyama muscular dystrophy, outpatient treatment may be possible. In addition to the family doctor, internists, neurologists, orthopedists and cardiologists can be called in for this purpose. In the further course, the doctor responsible will also involve a physiotherapist in the therapy.
Treatment & Therapy
There is no therapy aimed at curing FCMD because there is no way of replacing the genetically incorrectly encoded transmembrane protein fukutin with correctly encoded fukutin. Applied treatments and therapies serve to delay the course of the disease as much as possible and to have a positive influence on the quality of life of the children.
Physiotherapy exercises help to compensate for motor deficits a little and to slow down the progression towards joint contracture, i.e. towards joint stiffening and the process of muscle atrophy. In the case of acute orthopedic or other problems, individual intervention is carried out, including surgical interventions if necessary.
In many cases, additional anticonvulsant treatments are necessary to prevent epileptic or other convulsive seizures. Gastroesophageal reflux often occurs and requires surgical intervention in addition to drug treatment. Particular attention is paid to monitoring respiratory and cardiac function.
Especially in the advanced stage of the disease, problems increase, which are one of the main causes of death and therefore require close attention. Ultimately, the treatments and therapies help to improve the quality of life. Acute interventions to overcome acute shortness of breath or to overcome acute heart problems with imminent cardiac arrest are immediately life-prolonging.
Outlook & Forecast
The prospects for Fukuyama muscular dystrophy are poor. However, Europeans rarely have to fear an illness. The main distribution area is in Japan. One to two children in every 50,000 are born there with Fukuyama muscular dystrophy. The cause of the symptoms lies in a genetic defect. According to current scientific knowledge, this cannot be treated.
Life expectancy is greatly reduced. Most of those affected do not live to be more than ten years old. Depending on the severity of the symptoms, much earlier deaths are also possible. The quality of life also suffers. There are now many approaches available to curb complaints. These include above all physiotherapy, medication and breathing aids. However, the progressive development of Fukuyama muscular dystrophy cannot be slowed down overall.
Sick children need close supervision. Difficulty walking and standing are common. The number and intensity of the limitations increase significantly after the age of five. For parents and relatives, the diagnosis “Fukuyama muscular dystrophy” often means psychological stress. The treatment usually also includes your problem situation.
Prevention
Direct preventive measures that could prevent the occurrence of congenial Fukuyama muscular dystrophy do not exist because the disease is based exclusively on a genetic defect and the incorrectly encoded protein fukutin – the actual trigger of FCMD – cannot be replaced by correctly encoded fukutin.
For people of both sexes in whose families cases of FCMD have already been documented, a molecular genetic examination of the fukutin gene is recommended in order to obtain certainty as to whether a corresponding genetic defect is present.
Aftercare
In the case of Fukuyama muscular dystrophy, follow-up care is only possible to a very limited extent. The aftercare for the children is mostly on an outpatient basis, but sometimes inpatient aftercare is also necessary. Regular check-ups are important after diagnosis to monitor the development of the disease. Intensive child care is essential here.
Because Fukuyama muscular dystrophy cannot be treated, follow-up care can only alleviate the discomfort and symptoms. This serves to increase the quality of life of the child despite the illness. Physiotherapy is one way to compensate for muscle weakness and the resulting motor deficits and to slow down joint stiffness.
In some cases, additional orthopedic surgical procedures may also be necessary. Breathing aids and various medications are also recommended to curb the sometimes severe symptoms. Here it is fundamental that the regular intake of these drugs is checked.
Anticonvulsant treatments, which help to prevent epileptic seizures, are also important in follow-up care. Continuous monitoring of the child’s respiratory and cardiac function is also necessary. Fukuyama muscular dystrophy is an incurable disease and life expectancy is usually no more than ten years.
You can do that yourself
This very serious disease occurs mainly in Japan. Those affected usually die in infancy. These children depend on the help and protection of their parents as they need constant care. Parents must ensure that their affected child takes their medication reliably and accompany them to physiotherapy sessions. Deteriorations in the course of the disease must be recognized and presented to the doctors for additional treatment.
If the parents are overwhelmed with this, they should undergo supportive psychotherapy. Joining a self-help group is also recommended. The German Society for Muscle Diseases eV runs self-help groups throughout Germany that provide advice and support on site (www.dgm.org). Joining a self-help group can also bring relief to the child itself. It may also get to know children affected by muscle atrophy and exchange ideas. This is all the more important if the sick child is being bullied by other children in their immediate environment.
If the parents or relatives of a child suffering from Fukuyama muscular dystrophy want to have another child, they should seek genetic counseling. A molecular genetic test can show if and in whom the fukutin gene that causes the disease is damaged.
