Types of ataxia / muscular dystrophy

Ataxia 2

What is Ataxia?
The word “Ataxia”comes from the Greek word, “a taxis”, meaning “without order or incoordination”. People with Ataxia have problems with coordination because parts of the Nervous System that control movement and balance are affected. Ataxia may affect the Fingers, Hands, Arms, Legs, Body, Speech, and Eye movements. The word Ataxia is often used to describe a symptom of incoordination that can be associated with Infections, Injuries, other Diseases (or) Degenerative changes in the Central Nervous System. Ataxia is also used to denote a group of specific Degenerative diseases of the Nervous System called the Hereditary and Sporadic Ataxias.
How is Ataxia Diagnosed?
Diagnosis is based on a person’s medical history, family history and a complete Neurological evaluation including an MRI scan of the Brain. Various Blood tests may be performed to rule out other possible disorders which may present similar symptoms. Genetic Blood tests are now available for some types of Hereditary Ataxia to confirm a diagnosis or as a predictive test to determine if someone has inherited an Ataxia Gene known to affect other family members.
What are Common Symptoms?
Symptoms and time of onset vary according to the type of Ataxia. In fact, there are often variations even within the same family with the same type of Ataxia. Recessive disorders commonly cause symptoms to begin in childhood rather that adulthood. However, in recent years since Genetic testing has become available, it is now known that Friedreich’s Ataxia has an adult onset on some occasions. Dominant Ataxia often begins in the 20s or 30sor even later in life. Sometimes individuals may not show symptoms until they are in their 60s. 

Typically balance and coordination are affected at first. In coordination of hands, arms, and legs, and slurring of speech are other common symptoms. Walking becomes difficult and is characterized by walking with Feet placed further apart to compensate for poor balance. Impaired coordination of the arms and hands affect a person’s ability to perform tasks requiring fine motor control such as Writing and Eating. Slow Eye movements can be seen in some form of Ataxia. As time goes on, Ataxia can affect Speech and swallowing.

The Hereditary Ataxias are Degenerative disorders that progresses over for number of years. How severe will the disability become and whether the disease will lead to death depends on the type of Ataxia, the age of onset of symptoms and other factors that are poorly understood at this time. Respiratory complications can be fatal in a person who is bed bound or who has severe swallowing problems. Some persons with Friedreich’s Ataxia develop serious Cardiac problems too.

What is Sporadic Ataxia?
There is a large group of people who have symptoms of Ataxia that usually begins in adulthood and who have no known family history of this disease. This is called Sporadic Ataxia and it can be difficult to diagnose. There are many acquired and Hereditary causes of Ataxia that must be ruled out before a diagnosis of Sporadic Ataxia is done. Sporadic Ataxia can be either “pure cerebellar” if only the Cerebellum is affected or Cerebellar plus. If the Ataxia is accompanied by additional symptoms such as Neuropathy (Dysfunction of Peripheral Nerves); Dementia (Impaired Intellectual Function); or Weakness, Rigidity (or) Spasticity of the Muscles. Disability may be greater and progress more quickly with the Cerebellar plus form of Sporadic Ataxia. The Cerebellar plus is a form of Sporadic Ataxia which is also known as Sporadic Olivopontocerebellar Ataxia ( sporadic OPCA) or multiple system atrophy, Cerebellar type (MSA-C).
Causes of Ataxia
The Hereditary Ataxias are Genetic, which is caused by a defective Gene present from the start of a person’s life. All of us have Genes that have little mistakes or variations, but most of these do not cause disease, they are called Mutations. The Hereditary Ataxias can be divided into those that are dominantly inherited and those that are recessively inherited.
Affects Males and Females Equally
Autosomal dominant inheritance refers to a genetic pattern, where the Gene that causes Ataxia is located on one of the Autosomes and will affect males and females equally. An autosome can be any of the Chromosomes that not necessarily be Sex Chromosomes. All Genes come in pairs and dominantly inherited means that the Gene with the disease Mutation dominates over the normal copy of the Gene. Each child of a parent with an Autosomal dominant Ataxia Gene has a 50/50 chance of whether they will inherit the Ataxia Gene or not.
Genetic Patterns
Autosomal recessive inherited diseases also affect males and females equally but it takes a “double dose” of the Ataxia Gene to result in disease symptoms. Both parents must be carriers of the diseased Gene and each must pass on the Ataxia Gene to their child for the double dose that is needed to produce symptoms of the recessive disease. Each child of parents who are the carriers of a recessive disease have 25% chance of inheriting two Ataxia Genes to develop the disease and 50% chance of inheriting just one of the Ataxia Genes. Therefore being a carrier, there are 25% chances of inheriting no Ataxia Gene and be completely free from Ataxia. Because a single recessive Ataxia Gene does not cause symptoms, it can be passed on in a family for generations without being recognized. Therefore, there is often no “family history” of Ataxia if the disease is inherited as a recessive Gene. 

Ataxia Gene Identified in 1993:

The first Ataxia Gene was identified in 1993 for a dominantly inherited type. It was called “Spinocerebellar Ataxia type1 (SCA1)”. Subsequently, since additional dominant Genes were found, they were called SCA2, SCA3, etc. Generally the number behind the SCA refers to the order in which the Gene was found. At this time, 28 different Gene Mutations have been found. In other words, we have dominant Ataxia classifications from SCA1 to SCA 28. Genes have also been located for some of the recessive Ataxias, the most common being Friedreich’s Ataxia (FA).
Affects the Nervous System:
The various abnormal Genes that cause Ataxia have in common, is that they make abnormal Proteins that affect Nerve Cells, primarily in the Cerebellum (and other parts of the Brain) and the Spinal Cord. The details of which parts of the Nervous System are most affected vary with the different types of Ataxia. All forms of Ataxia cause poor coordination but some forms also cause additional symptoms that make it easier to distinguish one from the other. 

Ataxia Results in the Degeneration of Nerve Cells:
Eventually the affected Nerve Cells begin to function poorly and ultimately degenerate. As the disease progresses, Muscles become less and less responsive to commands from the Brain, causing coordination problems to become more pronounced. Those affected by poor coordination will notice poor balance when walking, inability to run, clumsiness of the hands, a change in speech, or abnormal eye movements.

What are the types of ataxia?
  • Ataxia Telangiectasia (A-T)
  • Charcot-Marie-Tooth Disorder (CMT)
  • Episodic Ataxia
  • Gluten Ataxia
  • Hereditary Spastic Paraplegia (HSP)
  • Marie’s Ataxia
  • Olivopontocerebellar Atrophy (OPCA)
  • Paraneoplastic Cerebellar Degeneration (PCD)
  • Post-Infectious Ataxia
  • Spinocerebellar Ataxias (SCA’s)(Type 1 to19)
  • Friedreich’s Ataxia

Please Note: That till date there are 40 different types of Identified Ataxia’s and it’s believed in future more will be Identified, so all the types of Ataxia’s have not been listed here as this page is under construction.

What Causes Ataxia?
Most often, Ataxia is caused by loss of function in the part of the Brain which serves as the “co-ordination centre”, which is the Cerebellum. The Cerebellum is located toward the back and lower part of the Head. The right side of the Cerebellum controls co-ordination on the right side of the body, and the left side controls co-ordination on the left. The central part of the Cerebellum is involved in co-ordinating the very complex movements of gait (or) walking. Other parts of the Cerebellum help to co-ordinate eye movements, speech and swallowing. 

Ataxia may also be caused by dysfunction of the pathways leading into and out of the Cerebellum. Information comes into the Cerebellum from the Spinal Cord and other parts of the Brain. Signals from the Cerebellum go out to the Spinal Cord and to the Brain. Although the Cerebellum does not directly control strength (“motor function”) or feeling (“sensory function”), the motor and sensory pathways must work properly to provide the correct input into the Cerebellum.
Thus, a person with impaired strength or sensation may notice clumsiness or poor co-ordination and the doctor may conclude that the person has Ataxia.

Difference Between Hereditary Dominant Ataxia and Recessive Ataxia
It is important that we understand the distinction between Hereditary Dominant Ataxia and Recessive Ataxia (like Friedreich’s Ataxia). Here is a little information to help us understand this distinction.
Dominant Ataxia
ATAXIA when hereditary is passed directly from afflicted parent to child. Each child faces 50-50 odds of inheriting a dominant Ataxia and being able to pass the Gene Mutation on to the next generation. If the child does not develop Ataxia, he (or) she will not be able to pass the Gene Mutation on to the next generation. Symptoms for the dominant Ataxias may appear at any age, most commonly in the 20’s and 30’s. 

Recessive Ataxia
ATAXIA when recessive will appear only if the child receives the defective Gene from both parents. The parents are called carriers and are not affected. Each child of these parents faces a 25% chance of having a Recessive Ataxia, and a 50% chance of being a carrier without showing any symptoms, and a 25% chance of being neither victim or carrier. Symptoms usually appear in the teenage years.
The most common Recessive Ataxia is Friedreich’s Ataxia. Dominant Ataxias are relatively rare although more victims of these disorders are being found these days due to the development of sophisticated DNA testing. Ataxia is most commonly misdiagnosed at Multiple Sclerosis.

Types of Ataxia
Ataxia Telangiectasia (A-T)
Ataxia Telangiectasia (A-T) is a rare, progressive, neurodegenerative childhood disease that affects the nervous system and other body systems. The first signs of the disease, which include lack of balance and slurred speech, usually occur during the first decade of life. The hallmarks of A-T are Ataxia (lack of muscle control) and Telangiectasias (tiny, red “spider” veins), which appear in the corners of the eyes or on the surface of ears and cheeks soon after the onset of Ataxia. Individuals with A-T are predisposed to Leukemia and Lymphoma and are extremely sensitive to radiation exposure. Many individuals with A-T have a weakened immune system, making them susceptible to recurrent respiratory infections. Other features of the disease may include mild Diabetes Mellitus, premature graying of the hair, difficulty swallowing which causes choking and/or drooling and slowed growth. Children with A-T usually maintain normal or above normal intelligence. 

Charcot-Marie-Tooth Disorder (CMT)
Charcot-Marie-Tooth disorder (CMT) is an inherited Neurological disease characterized by a slowly progressive degeneration of the Muscles in the foot, lower leg, hand, forearm and a mild loss of sensation in the limbs, fingers and toes. The first sign of CMT is generally a high arched foot or gait disturbances. Other symptoms of the disorder may include foot bone abnormalities such as high arches and hammer toes, problems with hand function and balance, occasional lower leg and forearm muscle cramping, loss of some normal reflexes, occasional partial sight and/or hearing loss, and in some patients, Scoliosis (curvature of the Spine). CMT is a disorder of Genetic Heterogeneity, in which Mutations in different Genes can produce the same clinical symptoms. In CMT, there are not only different Genes but different patterns of inheritance. The most common type, CMT1A is inherited in an autosomal dominant pattern. This means that if one parent has CMT there is a 50 percent chance of passing the disease on to each child. Other types are autosomal recessive or sex-linked CMT. Each type is characterized by symptoms ranging from severe weakness and wasting of leg and hand muscles to very mild symptoms or no symptoms at all. Full expression of CMT’s clinical symptoms generally occurs by age 30. The more severe symptoms are related to an earlier age of onset.

Autosomal dominant Episodic Ataxias are a clinically and genetically heterogeneous group of conditions characterized by recurrent paroxysmal attacks of generalized Cerebellar Ataxia usually starting during childhood or adolescence. Two forms of Episodic Ataxia have been identified: Episodic Ataxia 1 and Episodic Ataxia 2.   In Episodic Ataxia Type 1 EA1), brief attacks are triggered by startle or exercise and are associated with interictal Myokymias.  EA1 is caused by Mutations in the voltage-gated Potassium channel Gene KCNA1, mapped on Chromosome 12p.  In Episodic Ataxia type 2 (EA2), attacks are more prolonged (up to several hours or days) often provoked by emotional or physical stress (not by startle) and associated with an interictal Nystagmus.  Acetazolamide responsiveness is a common feature of EA2.  Attacks include severe Statokinetic Ataxia, Dysarthia and Nystagmus, sometimes Vertigo, Diplopia or Headache, and rarely Oscillopsia.  In addition to an interictal Nystagmus, some patients may develop a mild permanent and progressive Cerebellar Ataxia.  Patients usually remain autonomous.  CT or MRI scans may disclose a Cerebellar Atrophy predominating on the anterior vermis.  EA2 results from Mutations in the CACNA1A Gene, located on Chromosome 19p, which codes for the pore-forming 1A subunit of a P/Q-type voltage-dependent Calcium channel.  P/Q-type channels have a broad neuronal expression but are mainly expressed in the Cerebellum and are the major Calcium channels in Purkinje’s cells. They are involved in the control of membrane excitability and neurotransmitter release.

Gluten Ataxia
Gluten sensitivity may result in loss of coordination. This disease is known as Gluten Ataxia. Gluten Ataxia is a common Neurological manifestation of Gluten sensitivity and it unknown why some patients with Gluten sensitivity present solely with neurological dysfunction when others present with Gastrointentestinal symptoms or an itchy skin rash.  Although the Cerebellum (the part of the Brain responsible for coordination)and in particular the Purkinje cells (output neurons of the Cerebellum) appear to be most susceptible to damage in patients with Gluten Ataxia, other areas of the brain are not spared.  Study results show that patients with Gluten Ataxia have antibodies against Purkinje cells and also that antibodies against Gluten (antigliadin antibodies) cross-react with Purkinje cells.  Eliminating these antibodies through strict adherence to a Gluten-free diet may have important therapeutic implications for patients with Gluten Ataxia.

Hereditary Spastic Paraplegia (HSP)
Hereditary Spastic Paraplegia or Hereditary Spastic Paraparesis is a name used to represent a group of inherited degenerative Spinal Cord disorders characterized by a slow, gradual, progressive weakness and spasticity (stiffness) of the legs. Symptoms may be first noticed in early childhood, or at any age through adulthood. Initial symptoms may include difficulty with balance, weakness and stiffness in the legs, muscle spasms and dragging the toes when walking. In some forms of the disorder, bladder symptoms (such as incontinence) may appear, or the weakness and stiffness may spread to other parts of the body. Rate of progression and the severity of symptoms is quite variable even among members of the same family. Anticipation may occur in some families, with symptoms of the disorder beginning earlier and more severely in successive generations. HSP rarely results in complete loss of lower limb mobility, although mobility devices such as Canes, Walkers, or Wheel-chairs may be necessary. In some patients, the symptoms continue to increase throughout their life. For others, symptoms may begin in early childhood, worsen for a few years, then level off after adolescence.

Marie’s Ataxia
Marie’s Ataxia is a neuromuscular syndrome inherited as a dominant trait. Also known as Pierre Marie’s Disease or Hereditary Cerebellar Ataxia, it is characterized by a later onset of neurological and coordination disturbances. The syndrome usually begins between Thirty and Forty years of age and may not be as disabling as Friedreich’s Ataxia. Initially, those affected may walk unsteadily and tend to fall frequently. Loss of coordination in the arms and speech disturbances may also occur. In later stages slight loss of vision, and loss of pain or touch sensations may also occur. Tremors may develop when conscious motion is attempted. Swallowing and clearing of secretions may eventually become difficult if the throat muscles are affected.

Olivopontocerebellar Atrophy (OPCA)
Olivopontocerebellar Atrophy (OPCA) refers to a group of Ataxias characterized by progressive neurological degeneration affecting the Cerebellum, the pons and the inferior Olives. OPCA may be classified based on clinical, genetic, or neuropathological findings; thus, there are many classifications of the disorder. Among the different classifications there is wide variation in severity and age of onset. The symptoms of OPCA differ from person to person. Most patients experience difficulty with balance and coordination of the legs and arms (Ataxia) and slurred speech (Dysarthria). Other symptoms may include muscle spasms or weakness and stiffness of the muscles; numbness or tingling of the hands or feet; tremor (shaking) of the hand or arm; reduction or slowness of movements; loss of thinking and/or memory skills; difficulty controlling the bladder or bowels; and feeling faint when standing up. Some patients also have fatigue and/or trouble with sleep. Generally symptoms of OPCA begin in mid-adult life and progress slowly over the course of many years.

Paraneoplastic Cerebellar Degeneration (PCD)
Neurological Paraneoplastic Syndromes are a group of rare degenerative diseases linked to the body’s immune response to cancer. Symptoms include gradual loss of the ability to walk, shaking hands, dizziness, difficulty talking, chaotic eye movements and other motor problems. The symptoms, which vary from mild to severe, may precede the discovery of cancer by months or even years and sufferers may initially be misdiagnosed as suffering from a stroke, alcoholism, Parkinson’s and other diseases.

Post-Infectious Ataxia
Post Infectious Ataxia results in the sudden onset of incoordination, due to a complication of infectious disease.  In childhood, this is most commonly caused by viral infection, usually Varicella (Chickenpox).  Volitional (intentional) movement is impaired, so there is awkwardness of usually well-coordinated movement.  Movements of the extremities, trunk, extraocular movements of the globes (eyeballs), or the speech musculature may be impaired. The condition usually resolves without disease-specific treatment. Complications are rare, but may result in swelling of the cerebellum and a long-lasting incoordination of voluntary muscles.

Spinocerebellar Ataxias (SCA’s)
Spinocerebellar Ataxias (SCA) are a heterogeneous group of neurodegenerative disorders characterized by progressive Ataxia, Dysarthria, swallowing difficulties and other differing and less consistent features. SCAs are autosomal dominant disorders. Their overlapping clinical presentation, variable onset and severity has complicated diagnosis and classification.
Though the different types of SCAs are due to defects in different Genes, they have a common mechanism involving expansion of a CAG repeat in the Gene. Genetic testing is performed by both PCR and southern blot analysis. Genetic counseling and testing is recommended for individuals with symptoms of SCA, or at-risk asymptomatic individuals who are at least 18 years of age.

SCA1      SCA2      SCA3      SCA4
SCA5      SCA6      SCA7      SCA8
SCA9      SCA10    SCA11    SCA12
SCA13    SCA14    SCA15    SCA16
SCA17    SCA18    SCA19
What is Friedreich’s Ataxia?
Friedreich’s Ataxia is an inherited disease that causes progressive damage to the nervous system resulting in symptoms ranging from muscle weakness and speech problems to heart disease. It is named after the physician Nicholas Friedreich, who first described the condition in the 1860’s. “Ataxia,” which refers to coordination problems such as clumsy or awkward movements and unsteadiness, occurs in many different diseases and conditions. In Friedreich’s Ataxia, Ataxia results from the degeneration of Nerve Tissue in the Spinal Cord and of Nerves that control muscle movement in the arms and legs. The Spinal Cord becomes thinner and Nerve Cells lose some of their Myelin Sheath – the insular covering on all Nerve Cells that helps conduct Nerve impulses.
What are the signs and symptoms?
Symptoms usually begin between the ages of 5 and 15 but can, on rare occasions, appear as early as 18 months or as late as 30 years of age. The first symptom to appear is usually difficulty in walking, or gait Ataxia. The Ataxia gradually worsens and slowly spreads to the arms and then the trunk. Foot deformities such as clubfoot, flexion (involuntary bending) of the toes, hammer toes, or foot inversion (turning inward) may be early signs. Over time, muscles begin to weaken and waste away, especially in the feet, lower legs, and hands, and deformities develop. Other symptoms include loss of tendon reflexes, especially in the knees and ankles. There is often a gradual loss of sensation in the extremities, which may spread to other parts of the body. Dysarthria (slowness and slurring of speech) develops, and the person is easily fatigued. Rapid, rhythmic, involuntary movements of the eyeball (Nystagmus) is common. Most people with Friedreich’s Ataxia develop Scoliosis (a curving of the Spine to one side), which, if severe, may impair breathing. 

Other symptoms that may occur include Chest pain, shortness of breath, and Heart palpitations. These symptoms are the result of various forms of Heart disease that often accompany Friedreich’s Ataxia, such as Cardiomyopathy (enlargement of the Heart), Myocardial Fibrosis (formation of fiber-like material in the muscles of the heart), and Cardiac failure. Heart rhythm abnormalities such as Tachycardia (fast Heart rate) and Heart block (impaired conduction of Cardiac impulses within the Heart) are also common. About 20 percent of people with Friedreich’s Ataxia develop Carbohydrate intolerance and 10 percent develop diabetes Mellitus. Some people lose hearing or eyesight.

The rate of progression varies from person to person. Generally, within 15 to 20 years after the appearance of the first symptoms, the person is confined to a Wheelchair, and in later stages of the disease, individuals become completely incapacitated. Life expectancy is greatly affected, and most people with Friedreich’s Ataxia die in early adulthood if there is significant heart disease, the most common cause of death. However, some people with less severe symptoms of Friedreich’s Ataxia live much longer.

How is Friedreich’s Ataxia diagnosed?
Doctors diagnose Friedreich’s Ataxia by performing a careful clinical examination, which includes a medical history and a thorough physical examination. Tests that may be performed include:

  • electromyogram (EMG), which measures the electrical activity of muscle cells,
  • Nerve conduction studies, which measure the speed with which Nerves transmit impulses,
  • electrocardiogram (EKG), which gives a graphic presentation of the electrical activity or beat pattern of the heart,
  • Echocardiogram, which records the position and motion of the Heart muscle,
  • Magnetic Resonance Imaging (MRI) or Computed Tomography (CT) Scan, which provides a picture of the Brain and Spinal Cord,
  • Spinal tap to evaluate the Cerebrospinal Fluid,
  • Blood and Urine tests to check for elevated Glucose levels, and
  • Genetic testing to identify the affected Gene.

How is Friedreich’s Ataxia inherited?
Friedreich’s Ataxia is an autosomal recessive disease, which means the patient must inherit two affected Genes, one from each parent, for the disease to develop. A person who has only one abnormal copy of a Gene for a recessive genetic disease such as Friedreich’s Ataxia is called a carrier. A carrier will not develop the disease but could pass the affected Gene on to his or her children. If both parents are carriers of the Friedreich’s Ataxia gene, their children will have a 1 in 4 chance of having the disease and a 1 in 2 chance of inheriting one abnormal Gene that they, in turn, could pass on to their children. About one in 90 Americans of European ancestry carries one affected Gene.

Humans have two copies of each gene – One inherited from the Mother and one from the Father. Genes are located at a specific place on each of an individual’s 46 Chromosomes, which are tightly coiled chains of DNA containing millions of chemicals called bases. These bases – Adenine, Thymine, Cytosine and Guanine – are abbreviated as A, T, C, and G. Certain bases always “pair” together (A with T; C with G), and different combinations of base pairs join in sets of three to form coded messages.

These coded messages are “recipes” for making Amino Acids, the building blocks of Proteins. By combining in long sequences, like long phone numbers, the paired bases tell each cell how to assemble different Proteins. Proteins make up Cells, Tissues and specialized Enzymes that our bodies need to function normally. The Protein that is altered in Friedreich’s Ataxia is called Frataxin.

In 1996, an international group of scientists identified the cause of Friedreich’s Ataxia as a defect in a Gene located on Chromosome 9. Because of the inherited abnormal code, a particular sequence of bases (GAA)is repeated too many times. Normally, the GAA sequence is repeated 7 to 22 times, but in people with Friedreich’s Ataxia it is repeated 800 to 1,000 times. This type of abnormality is called a triplet repeat expansion and has been implicated as the cause of several dominantly inherited diseases. Friedreich’s Ataxia is the first known recessive Genetic disease that is caused by a triplet repeat expansion. Although about 98 percent of Friedreich’s Ataxia carriers have this particular Genetic triplet repeat expansion, it is not found in all cases of the disease. A very small proportion of affected individuals have other Gene coding defects responsible for causing disease.

The triplet repeat expansion apparently disrupts the normal assembly of Amino Acids into Proteins, greatly reducing the amount of Frataxin that is produced. Research suggests that without a normal level of Frataxin, certain cells in the body (especially Brain, Spinal Cord, and muscle cells) cannot manage the normal amounts of “oxidative stress” which the Mitochondria, the energy-producing power plants of cells produce. This clue to the possible cause of Friedreich’s Ataxia came after scientists conducted studies using a Yeast Protein with a chemical structure similar to human Frataxin. They found that the shortage of this Protein in the Yeast cell led to a toxic buildup of iron in the cell’s Mitochondria. When the excess iron reacted with Oxygen, free radicals were produced. Although free radicals are essential molecules in the body’s metabolism, they can also destroy cells and harm the body. Research continues on this subject (see section on “What research is being done?”).

Can Friedreich’s Ataxia be cured or treated?
As with many degenerative diseases of the nervous system, there is currently no effective cure or treatment for Friedreich’s Ataxia. However, many of the symptoms and accompanying complications can be treated to help patients maintain optimal functioning as long as possible. Diabetes, if present, can be treated with diet and medications such as insulin, and some of the Heart problems can be treated with medication as well. Orthopedic problems such as foot deformities and Scoliosis can be treated with braces or surgery. Physical therapy may prolong use of the arms and legs. Scientists hope that recent advances in understanding the Genetics of Friedreich’s Ataxia may lead to breakthroughs in treatment
This Information on Ataxia has been taken from NAF Website with their permission and it is recommended to visit www.ataxia.org for further details on Ataxia.

What is Muscular Dystrophy?
The Muscular Dystrophies (MD) are a group of more than 30 Genetic diseases characterized by progressive weakness and degeneration of the Skeletal muscles that control movement. Some forms of MD are seen in infancy or childhood, while others may not appear until middle age or later. The disorders differ in terms of the distribution and extent of muscle weakness (some forms of MD also affect Cardiac muscle), age of onset, rate of progression, and pattern of inheritance. 

Duchenne MD is the most common form of MD and primarily affects boys. It is caused by the absence of Dystrophin, a Protein involved in maintaining the integrity of muscle. Onset is between 3 and 5 years and the disorder progresses rapidly. Most boys are unable to walk by age 12, and later need a respirator to breathe. Girls in these families have a 50 percent chance of inheriting and passing the defective Gene to their children. Boys with Becker MD (very similar to but less severe than Duchenne MD) have faulty or not enough Dystrophin.

Facioscapulohumeral MD usually begins in the teenage years. It causes progressive weakness in muscles of the face, arms, legs, and around the shoulders and chest. It progresses slowly and can vary in symptoms from mild to disabling.

Myotonic MD is the disorder’s most common adult form and is typified by prolonged muscle Spasms, Cataracts, Cardiac abnormalities, and Endocrine disturbances. Individuals with myotonic MD have long, thin faces, drooping eyelids, and a swan-like neck.

Is there any treatment?
There is no specific treatment to stop or reverse any form of MD. Treatment may include physical therapy, respiratory therapy, speech therapy, orthopedic appliances used for support, and corrective orthopedic surgery. Drug therapy includes Corticosteroids to slow muscle degeneration, anticonvulsants to control seizures and some muscle activity, immunosuppressants to delay some damage to dying muscle cells, and antibiotics to fight respiratory infections. Some individuals may benefit from occupational therapy and assistive technology. Some patients may need assisted ventilation to treat respiratory muscle weakness and a pacemaker for Cardiac abnormalities.

What is the prognosis?
The prognosis for people with MD varies according to the type and progression of the disorder. Some cases may be mild and progress very slowly over a normal lifespan, while others produce severe muscle weakness, functional disability, and loss of the ability to walk. Some children with MD die in infancy while others live into adulthood with only moderate disability.

  • Duchenne Muscular Dystrophy (DMD)
    (Also known as Pseudohypertrophic)
  • Becker Muscular Dystrophy (BMD)
  • Emery-Dreifuss Muscular Dystrophy (EDMD)
  • Limb-Girdle Muscular Dystrophy (LGMD)
  • Facioscapulohumeral Muscular Dystrophy (FSH or FSHD)
    (Also known as Landouzy-Dejerine)
  • Myotonic Dystrophy (MMD)
    (Also known as DM or Steinert Disease)
  • Oculopharyngeal Muscular Dystrophy (OPMD)
  • Distal Muscular Dystrophy (DD) (Miyoshi)
  • Congenital Muscular Dystrophy (CMD)
  • Duchenne Muscular Dystrophy (DMD)
    Definition – One of Nine types of Muscular Dystrophies, a group of Genetic, degenerative diseases primarily affecting voluntary muscles.
    Cause – An absence of Dystrophin, a Protein that helps keep muscle cells intact.
    Onset – Early childhood – about 2 to 6 years.
    Symptoms – Generalized weakness and muscle wasting first affecting the Muscles of the hips, pelvic area, thighs and shoulders. Calves are often enlarged.
    Progression – DMD eventually affects all voluntary muscles, and the Heart and breathing muscles. Survival is rare beyond the early 30s. A less severe variant is Becker Muscular Dystrophy.
    Inheritance – X-linked recessive. DMD primarily affects boys, who inherit the disease through their mothers. Women can be carriers of DMD but usually exhibit no symptoms.
  • Becker Muscular Dystrophy (BMD)
    Definition – One of nine types of Muscular Dystrophy, a group of Genetic, degenerative diseases primarily affecting voluntary muscles.
    Cause – Insufficient production of Dystrophin, a Protein that helps keep muscle cells intact.
    Onset – Adolescence or adulthood.
    Symptoms – Generalized weakness and wasting first affecting the muscles of the Hips, Pelvic area, Thighs and Shoulders. Calves are often enlarged. BMD is similar to Duchenne Muscular Dystrophy but often much less severe. There can be significant Heart involvement.
    Progression – Disease progresses slowly and with variability but can affect all voluntary muscles. Most with BMD survive well into mid- to late adulthood.
    Inheritance – X-linked recessive. BMD primarily affects boys and men, who inherit the disease through their mothers. Women can be carriers but usually exhibit no symptoms.
  • Emery-Dreifuss Muscular Dystrophy(EDMD)
    Definition – One of nine types of Muscular Dystrophy, a group of Genetic, degenerative diseases primarily affecting voluntary muscles.
    Cause – Mutations in the Genes that produce Emerin, Lamin A or Lamin C, Proteins in the Membrane that surrounds the Nucleus of each muscle cell.
    Onset – Usually by 10 years of age.
    Symptoms – Weakness and wasting of shoulder, upper arm and Calf muscles; joint stiffening; fainting (because of Cardiac abnormalities).
    Progression – Disease usually progresses slowly. Cardiac complications are common and sometimes require a pacemaker.
    Inheritance -Can be X-linked recessive, primarily affecting males, who inherit the disease through their mothers. Another type is autosomal dominant, meaning it can be inherited through either parent; an autosomal recessive type occurs when a faulty Gene is inherited from each parent.
  • Limb-Girdle Muscular Dystrophy (LGMD)
    Definition – One of nine types of Muscular Dystrophy, a group of Genetic, degenerative diseases primarily affecting voluntary muscles.
    Cause – A Mutation in any of at least 15 different Genes that affect Proteins necessary for muscle function.
    Onset -Childhood to adulthood.
    Symptoms – Weakness and wasting first affecting the muscles around the shoulders and hips (limb girdles).
    Progression – Usually progresses slowly, with Cardiopulmonary complications sometimes occurring in later stages of the disease.
    Inheritance -Some types are autosomal dominant, meaning LGMD is inherited from one parent. Other types are autosomal recessive and occur when a faulty Gene is inherited from each parent.
  • Facioscapulohumeral Muscular Dystrophy (FSH or FSHD)
    Also known as Landouzy-Dejerine
    Definition – One of nine types of Muscular Dystrophy, a group of Genetic, degenerative diseases primarily affecting voluntary muscles.
    Cause – A missing piece of DNA on Chromosome 4.
    Onset – Usually by age 20.
    Symptoms – Weakness and wasting of the muscles around the eyes and mouth, and of the shoulders, upper arms and lower legs initially, with later weakness of abdominal muscles and sometimes hip muscles.
    Progression – Progresses slowly with some periods of rapid deterioration. Disease may span many decades.
    Inheritance – Autosomal dominant; the disease may be inherited through either the father or the mother, or it may occur without a family history.
  • Myotonic Muscular Dystrophy (MMD)
    Also known as Steinert Disease, Dystrophia Myotonica (DM)
    Definition – One of nine types of Muscular Dystrophy, a group of Genetic, degenerative diseases primarily affecting voluntary muscles.
    Cause – A repeated section of DNA on either Chromosome 19 or Chromosome 3.
    Onset – Congenital form appears at birth. More common form may begin in teen or adult years.
    Symptoms – Generalized weakness and muscle wasting first affecting the face, lower legs, forearms, hands and neck, with delayed relaxation of muscles after contraction common. Other symptoms involve the Gastrointestinal system, vision, heart or respiration. Learning disabilities occur in some cases. Congenital Myotonic Dystrophy is the more severe form.
    Progression – Progression is slow, sometimes spanning 50 to 60 years.
    Inheritance – Autosomal dominant; the disease may be inherited through either the father or the mother.
  • Oculopharyngeal Muscular Dystrophy (OPMD)
    Definition – One of nine types of Muscular Dystrophy, a group of Genetic, degenerative diseases primarily affecting voluntary muscles.
    Cause – A faulty Gene for poly(A)-binding Protein nuclear1 (PABPN1), which is suspected to lead to production of extra chemical material that causes formation of clumps in the muscle cells.
    Onset – Usually not until the 40s or 50s.
    Symptoms – OPMD first causes weakness of the muscles of the eyelids and throat; weakness of facial and limb muscles often occurs later. Swallowing problems and difficulty keeping the eyes open are common problems.
    Progression – Slow.
    Inheritance – May be autosomal dominant, meaning OPMD is inherited from one parent; or autosomal recessive, occurring when a faulty Gene is inherited from each parent.
  • Distal Muscular Dystrophy (DD)
    Definition – A class of Muscular Dystrophies that primarily affect Distal Muscles, which are those of the lower arms, hands, lower legs and feet. Muscular Dystrophies in general are a group of Genetic, degenerative diseases primarily affecting voluntary muscles.
    Cause – A Mutation in any of at least eight Genes that affect Proteins necessary to the function of muscles.
    Onset – childhood to adulthood
    Symptoms – Weakness and wasting of muscles of the hands, forearms and lower legs.
    Progression – Slow progression; not life-threatening.
    Inheritance – May be autosomal dominant, meaning a faulty Gene is inherited from one parent; or autosomal recessive, occurring when a faulty Gene is inherited from each parent.
  • Congenital Muscular Dystrophy (CMD)
    Definition – A class of Muscular Dystrophies that show themselves at or near birth. Muscular dystrophies in general are a group of Genetic, degenerative diseases primarily affecting voluntary muscles.
    Cause – Genetic Mutations affecting some of the Proteins necessary for muscles and sometimes for the Eyes and or Brain.
    Onset – At or near birth.
    Symptoms – Generalized muscle weakness with possible joint stiffness or looseness. Depending on the type, CMD may involve Spinal curvature, respiratory insufficiency, mental retardation or learning disabilities, Eye defects or seizures.
    Progression – Varies with type; many are slowly progressive; some shorten life span.
    Inheritance – Autosomal recessive or autosomal dominant; these diseases are sometimes inherited through both parents and sometimes inherited from one parent. They can also occur spontaneously because of a newly developed Genetic flaw (mutation).

For more information about Muscular Dystrophies, Please log on to http://www.mda.org/ MDA/USA

Help us to share help

One Response to Types of ataxia / muscular dystrophy

  1. Pawan says:

    I had gone thru ataxia blog . it’s nice and informative. My mother is suffering from spine celebar ataxia. If any news regarding any chances please let me know.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s