What is Fukuyama Muscular Dystrophy?
Fukuyama congenital muscular dystrophy (FCMD) is an inherited type of muscular dystrophy. Its symptoms are present from birth, and the disorder progresses slowly through childhood.
Muscular dystrophy (MD) is a collective term that refers to a group of more than 30 diseases. The common characteristic of all the diseases is that they cause muscle weakness and a progressive loss of muscle tissue. The congenital forms of MD, of which FCMD is one, are present at birth, while some other forms of the disorder develop later in life. Unfortunately, there is no known cure for any of the diseases, including FCMD.
Symptoms of Fukuyama Muscular Dystrophy
Symptoms of FCMD usually appear first in early infancy and get progressively worse. Symptoms vary in severity from case to case, and not all children with FCMD will have the same symptoms.
Symptoms of FCMD can include:
- Weak, floppy muscles (hypotonia)
- Feeding difficulties
- Weak cry
- Vision impairment
- Speech problems
- Intellectual disability
- Swallowing difficulties
- Breathing difficulties
- Heart problems
What Causes Fukuyama Muscular Dystrophy?
Muscular dystrophy occurs when the body cannot produce the kinds of proteins needed to build and protect muscle cells. Genes control the production of these proteins, and each type of MD is characterized by a gene abnormality that causes the abnormal production of a particular protein.
In the case of FCMD, the affected protein is called fukutin. The FKTN gene carries instructions for producing fukutin, and people with FCMD have an abnormal change (mutation) in their FKTN gene. The genetic mutation interferes with the production of fukutin, and the lack of the protein causes muscle cells to be especially susceptible to damage. Fukutin also seems to play a role in early brain development
Is Fukuyama Muscular Dystrophy Hereditary?
FCMD is an inherited disorder. The disorder-causing gene mutations are inherited in an autosomal recessive pattern. This means that a child must inherit two copies of the gene mutation, one from each parent, to develop the disorder. People who have only one copy of the mutated gene will not develop FCMD but will be carriers who can pass the mutation on to their children. Two carrier parents have a 25 percent chance of having a child with FCMD with each pregnancy. Half of their pregnancies will produce a carrier, and a quarter of the pregnancies will produce a child with no mutated genes.
How Is Fukuyama Muscular Dystrophy Detected?
The earliest symptoms of FCMD are often apparent at birth, and other symptoms emerge as the disease progresses through infancy.
Early signs of FCMD include:
- Floppy muscles (hypotonia) at birth
- Feeding problems
- Weak cry
- Weak facial muscles that cause drooping eyelids or open mouth
- Progressive muscle weakness in infancy and childhood
- Stiff, rigid, and deformed joints that impair motor development
How Is Fukuyama Muscular Dystrophy Diagnosed?
If a doctor is presented with symptoms that look like muscular dystrophy, they will begin the diagnostic process by conducting a physical exam and gathering medical history. If it appears that a muscle disease is likely, several different tests can help determine if there is a muscle problem and which disease is the cause.
Possible diagnostic tests include:
- Creatine kinase (CK) test. Creatine kinase (CK) is a type of protein called an enzyme. CK in the blood is normal, but higher enzyme levels are created when muscles are damaged. A high CK level when there is no apparent muscle injury can show the presence of a muscle disease like FCMD.
- Electromyography. This test uses an electricity-sensing needle probe to measure muscle function. The test can detect muscle abnormalities that could be a sign of FCMD.
- Muscle biopsy. This test involves removing and examining a small amount of muscle tissue. A biopsy may be able to detect muscle abnormalities caused by FCMD.
- Brain imaging exams. Imaging exams such as magnetic resonance imaging (MRI) or computerized tomography (CT) may detect the brain abnormalities associated with FCMD.
- Genetic testing. These blood tests look for the specific genetic abnormalities that are responsible for different types of FCMD.
PLEASE CONSULT A PHYSICIAN FOR MORE INFORMATION.
How Is Fukuyama Muscular Dystrophy Treated?
There is no cure for FCMD, and no treatment will reverse the progression of its symptoms. With treatment, symptoms can sometimes be managed to help prevent severe, life-threatening complications. Possible treatment options include:
- Anti-convulsant drugs such as phenytoin, valproic acid, phenobarbitol, clonazepam, ethusuximide, primidone, corticotropin, or corticosteroids to control seizures
- Feeding assistance, including feeding tubes
- Physical therapy
- Respiratory therapy
- Speech therapy
How Does Fukuyama Muscular Dystrophy Progress?
FCMD symptoms progress slowly through infancy and childhood. Delays in motor, speech, and intellectual development are often severe and cause significant disabilities.
Potential complications of FCMD include:
- Limited mobility. Muscle weakness makes it hard to get around, and most children with FCMD never learn to walk.
- Respiratory problems. The muscles responsible for controlling breathing can be affected, making it difficult for people with FCMD to breathe easily on their own.
- Swallowing problems. Muscles that control the swallowing reflex can be affected. When this happens, maintaining proper nutrition may be difficult, and sometimes a feeding tube is necessary. Swallowing difficulties can also lead to the aspiration of food or liquids into the lungs, leading to potentially fatal respiratory infections.
- Heart problems. FCMD causes progressive damage to the heart muscle, and this heart damage often results in fatal complications.
Severe complications of FCMD are common, and most people with the disease don’t survive past late childhood or adolescence.
How Is Fukuyama Muscular Dystrophy Prevented?
There is no known way to prevent FCMD in someone born with a genetic mutation responsible for the disease. Parents with a family history of the disorder or who have had another child with FCMD are advised to consult a genetic counselor to assess their risk if they plan to have another child.
Fukuyama Muscular Dystrophy Caregiver Tips
Studies have shown that caring for someone with muscular dystrophy can significantly negatively impact the caregiver’s life. Caregivers are at risk for depression, sleep problems, stress, anxiety, relationship problems, and low self-esteem. Caregivers are also likely to have difficulty performing well at work, and many caregivers quit working entirely to care for their child.
Because of these risks, caregivers must take advantage of support systems to keep themselves healthy. The Muscular Dystrophy Association maintains a collection of resources for caregivers that includes educational resources, guides, and links to caregiver networks and support groups.
Many people with FCMD also suffer from other brain-related issues, a condition called co-morbidity. Here are a few of the disorders commonly associated with FCMD and other forms of MD:
Fukuyama Muscular Dystrophy Brain Science
Scientists don’t fully understand the role of fukutin in brain development, but it may be involved in a process called glycosylation. This process modifies the alpha (α)-dystroglycan protein so that it can function. Proper alpha (α)-dystroglycan function is essential in several different parts of the body. For example, alpha (α)-dystroglycan helps strengthen and stabilize muscle fibers. Without the functioning protein, muscle cells are vulnerable to damage and death over time.
In the brain, alpha (α)-dystroglycan seems to be involved in a process called neuronal migration. In this process, nerve cells that are born near the brain’s center in early development move toward the outer parts of the brain, where they become specialized brain structures. In FCMD, some cells continue to migrate past the point where they should normally stop. Instead, they move to the outer surface of the brain. There they form clusters that create a lumpy texture called cobblestone lissencephaly. This brain malformation is likely the cause of FCMD’s neurological symptoms.
Fukuyama Muscular Dystrophy Research
Title: Congenital Muscle Disease Study of Patient and Family Reported Medical Information (CMDPROS)
Principal Investigator: Gustavo Dziewczapolski, PhD
Congenital Muscle Disease International Registry
The Congenital Muscle Disease Patient and Proxy Reported Outcome Study (CMDPROS) is a longitudinal ten-year study to identify and trend care parameters, adverse events in the congenital muscle diseases using the Congenital Muscle Disease International Registry (CMDIR) to acquire necessary data for adverse event calculations (intake survey and medical records curation). To support this study and become a participant, we ask that you register in the CMDIR. You can do this by visiting www.cmdir.org. There is no travel required.
The registry includes affected individuals with congenital muscular dystrophy, congenital myopathy, and congenital myasthenic syndrome and registers through the late onset spectrum for these disease groups. The CMDIR was created to identify the global congenital muscle disease population to raise awareness, standards of care, clinical trials, and in the future, a treatment or cure. Simply put, we will not be successful in finding a treatment or cure unless we know who the affected individuals are, what the diagnosis is, and how the disease is affecting the individual.
Registering in the CMDIR means that you will enter demographic information and complete an intake survey. We would then ask that you provide records regarding the diagnosis and treatment of CMD, including genetic testing, muscle biopsy, pulmonary function testing, sleep studies, clinic visit notes, and hospital discharge summaries.
Title: Clinical Trial Readiness for the Dystroglycanopathies
Principal Investigator: Katherine Mathews, MD
University of Iowa
Iowa City, IA
Muscular dystrophies are a diverse group of inherited disorders characterized by progressive muscle weakness and wasting. The disorders are caused by mutations, or changes, in genes. Genes are tiny pieces of inherited material (DNA) that direct the body to make certain kinds of proteins.
In this study, researchers will examine the clinical presentation of muscular dystrophy caused by abnormal glycosylation of alpha-dystroglycan. Patients with dystroglycanopathies could have mutations in any one of the 18 currently identified genes or evidence of dystroglycanopathy in biopsied muscle tissue. Symptoms range from congenital muscular dystrophy that may involve the brain and eye through an adult-onset limb-girdle muscular dystrophy.
The study involves a clinical evaluation at the University of Iowa. The evaluation includes muscle strength and motor ability testing, lung function testing, quality of life and activity assessment, and a review of past medical history. Portions of this evaluation will be repeated yearly. Financial assistance is available for travel to Iowa City. Support is also available for genetic testing for people with a dystroglycanopathy diagnosis based on muscle or skin biopsy analysis.
Knowledge gained from this study will improve healthcare recommendations for people with dystroglycanopathies and provide a baseline for further research, including potential treatment options.