DM1 is the most common form of myotonic muscular dystrophy diagnosed in children, with a prevalence ranging from 1 per 100,000 in Japan to 3-15 per 100,000 in Europe. The prevalence may be as high as 1 in 500 in regions such as Quebec, possibly due to the founder effect. In most populations, DM1 appears to be more common than DM2. However, recent studies suggest that type 2 may be as common as type 1 among people in Germany and Finland.

The incidence of congenital myotonic dystrophy is thought to be about 1:20,000. DM occurs in about 1 per 7,000–8,000 people and has been described in people from all over the world. It affects males and females approximately equally. About 30,000 people in the United States are affected.

Fukuyama congenital muscular dystrophy has a poor prognosis. Most children with FCMD reach a maximum mobility at sitting upright and sliding. Due to the compounded effects of continually worsening heart problems, impaired mental development, problems swallowing and additional complications, children with FCMD rarely live through adolescence, the disorder proves fatal by age 20.

Duchenne muscular dystrophy is a rare progressive disease which eventually affects all voluntary muscles and involves the heart and breathing muscles in later stages. As of 2013, the life expectancy is estimated to be around 25, but this varies. With excellent medical care males are often living into their 30s.

In rare cases, people with DMD have been seen to survive into their forties or early fifties, with proper positioning in wheelchairs and beds, and the use of ventilator support (via tracheostomy or mouthpiece), airway clearance, and heart medications. Early planning of the required supports for later-life care has shown greater longevity for people with DMD.

Curiously, in the mdx mouse model of Duchenne muscular dystrophy, the lack of dystrophin is associated with increased calcium levels and skeletal muscle myonecrosis. The intrinsic laryngeal muscles (ILMs) are protected and do not undergo myonecrosis. ILMs have a calcium regulation system profile suggestive of a better ability to handle calcium changes in comparison to other muscles, and this may provide a mechanistic insight for their unique pathophysiological properties. The ILM may facilitate the development of novel strategies for the prevention and treatment of muscle wasting in a variety of clinical scenarios.

The disease is found across 5 continents (30 countries) and is frequently seen in French Canadians, with a prevalence 1:1000. OPMD affects males and females equally, and affected individuals have been found in Europe (France), Jewish Ashkenazi, and Spanish Americans.

The progression of Becker muscular dystrophy is highly variable—much more so than Duchenne muscular dystrophy. There is also a form that may be considered as an intermediate between Duchenne and Becker MD (mild DMD or severe BMD).

Severity of the disease may be indicated by age of patient at the onset of the disease. One study showed that there may be two distinct patterns of progression in Becker muscular dystrophy. Onset at around age 7 to 8 years of age shows more cardiac involvement and trouble climbing stairs by age 20, if onset is around age 12, there is less cardiac involvement.

The quality of life for patients with Becker muscular dystrophy can be impacted by the symptoms of the disorder. But with assistive devices, independence can be maintained. People affected by Becker muscular dystrophy can still maintain active lifestyles.

DMD is caused by a mutation of the dystrophin gene at locus Xp21, located on the short arm of the X chromosome. Dystrophin is responsible for connecting the cytoskeleton of each muscle fiber to the underlying basal lamina (extracellular matrix), through a protein complex containing many subunits. The absence of dystrophin permits excess calcium to penetrate the sarcolemma (the cell membrane). Alterations in calcium and signalling pathways cause water to enter into the mitochondria, which then burst.

In skeletal muscle dystrophy, mitochondrial dysfunction gives rise to an amplification of stress-induced cytosolic calcium signals and an amplification of stress-induced reactive-oxygen species production. In a complex cascading process that involves several pathways and is not clearly understood, increased oxidative stress within the cell damages the sarcolemma and eventually results in the death of the cell. Muscle fibers undergo necrosis and are ultimately replaced with adipose and connective tissue.

DMD is inherited in an X-linked recessive pattern. Females typically are carriers for the disease, while males are affected. A female carrier will be unaware she carries a mutation until she has an affected son. The son of a carrier mother has a 50% chance of inheriting the defective gene from his mother. The daughter of a carrier mother has a 50% chance of being a carrier and a 50% chance of having two normal copies of the gene. In all cases, an unaffected father either passes a normal Y to his son or a normal X to his daughter. Female carriers of an X-linked recessive condition, such as DMD, can show symptoms depending on their pattern of X-inactivation. DMD has an incidence of one in 3,600 male infants. Mutations within the dystrophin gene can either be inherited or occur spontaneously during germline transmission.

Disruption of the blood-brain barrier has been seen to be a noted feature in the development of DMD.

Myotonic dystrophy is a genetic condition which is inherited in an autosomal dominant pattern and thus will be passed along to 50% of a carrier's offspring, on average. Myotonic dystrophy is one of several known trinucleotide repeat disorders. Certain areas of DNA have repeated sequences of two or three nucleotides.

Myotonic dystrophy (DM) is an inherited disease. A severe form of DM, congenital myotonic dystrophy, may appear in newborns of mothers who have DM. Congenital myotonic dystrophy can also be inherited via the paternal gene, although it is said to be relatively rare. Congenital means that the condition is present from birth.

The genetics of congenital muscular dystrophy are autosomal recessive which means two copies of an abnormal gene must be present

for the disease or trait to happen. In the case of collagen VI-deficient, it is autosomal dominant, which means a child could inherit the disease from only one copy of a gene present in only one parent.

The prevalence for congenital muscular dystrophy seems to be between 2.6-4.5 in 10,000 according to Reed, 2009. MDCIA, for example is due to a mutation in the LAMA-2 gene and is involved with the 6q2 chromosome.

The disorder is inherited with an X-linked recessive inheritance pattern. The gene is located on the X chromosome. Since women have two X chromosomes, if one X chromosome has the non-working gene, the second X chromosome will have a working copy of the gene to compensate, because of this ability to compensate, women rarely develop symptoms. All dystrophinopathies are inherited in an X-linked recessive manner. The risk to the siblings of an affected individual depends upon the carrier status of the mother. Carrier females have a 50% chance of passing the DMD mutation in each pregnancy. Sons who inherit the mutation will be affected; daughters who inherit the mutation will be carriers. Men who have Becker muscular dystrophy can have children, and all their daughters are carriers, but none of the sons will inherit their father's mutation.

Becker muscular dystrophy occurs in approximately 1.5 to 6 in 100,000 male births, making it much less common than Duchenne muscular dystrophy. Symptoms usually appear in men at about ages 8–25, but may sometimes begin later. Genetic counseling may be advisable when potential carriers or patients want to have children. Sons of a man with Becker muscular dystrophy do not develop the disorder, but daughters will be carriers (and some carriers can experience some symptoms of muscular dystrophy), the daughters' sons may develop the disorder.

The prognosis of this sub-type of MD indicates that the affected individual may eventually have feeding difficulties. Surgery, at some point, might be an option for scoliosis.

Scoliosis which is a sideways curve of the persons vertebrate, is determined by a variety of factors, including the degree (mild or severe), in which case if possible a brace might be used by the individual

These conditions are generally inherited, and the different muscular dystrophies follow various inheritance patterns. Muscular dystrophy can be inherited by individuals as an X-linked disorder, a recessive or dominant disorder. Furthermore, it can be a spontaneous mutation which means errors in the replication of DNA and spontaneous lesions. Spontaneous lesions are due to natural damage to DNA, where the most common are depurination and deamination.

Dystrophin protein is found in muscle fibre membrane; its helical nature allows it to act like a spring or shock absorber. Dystrophin links actin in the cytoskeleton and dystroglycans of the muscle cell plasma membrane, known as the sarcolemma (extracellular). In addition to mechanical stabilization, dystrophin also regulates calcium levels.

Recent studies on the interaction of proteins with missense mutations and its neighbors showed high degree of rigidity associated with central hub proteins involved in protein binding and flexible subnetworks having molecular functions involved with calcium.

In terms of possible research for Ullrich congenital muscular dystrophy one source indicates that cyclosporine A might be of benefit to individuals with this CMD type.

According to a review by Bernardi, et al., cyclosporin A (CsA) used to treat collagen VI muscular dystrophies demonstrates a normalization of mitochondrial reaction to rotenone.

In terms of the genetics LGMD is an inherited disorder, though it may be inherited as a dominant or recessive genetic defect. The result of the defect is that the muscles cannot properly form certain proteins needed for normal muscle function. Several different proteins can be affected, and the specific protein that is absent or defective identifies the specific type of muscular dystrophy. Among the proteins affected in LGMD are α, β, γ and δ sarcoglycans. The sarcoglycanopathies could be possibly amenable to gene therapy.

In terms of the mechanism of congenital muscular dystrophy, one finds that though there are many types of CMD the glycosylation of α-dystroglycan and alterations in those genes that are involved are an important part of this conditions pathophysiology

There is a variety of research under way targeted at various forms of limb-girdle muscular dystrophy. Among the methods thought to hold promise for treatment include gene transfer therapy, which works by inserting in cells of defective genes with a healthy gene.

According to a review by Bengtsson et al. some success with AAV-mediated gene therapies (for different disorders) have increased interest in researchers, with CRISPR/Cas9 and exon-skipping helping these therapeutic goals along. Limb-girdle muscular dystrophies has many different types which are due to different gene mutations. LGMD2D is caused by a mutation in the α-sarcoglycan gene.Future treatment could be had by gene therapy through recombinant adeno-associated vectors.

Conversely, according to a review by Straub, et al. there are several research issues that need to be targeted, the rareness of the disease, our poor understanding of the mechanism of LGMD2, and absence of patient cohorts, consequently biomarkers for individuals with LGMD2 are lacking. The review goes on to state that animal models for LGMD2 have been used to analyse therapeutic medications. Also adding that while prednisone has been used and has had positive effects on affected LGMD2 individuals there is still no evidence of its effectiveness in trials that are placebo-controlled

Currently no cure or specific treatment exists to eliminate the symptoms or stop the disease progression. A consistent diet planned with the help of a dietitian along with exercises taught by a speech therapist can assist with mild symptoms of dysphagia. Surgical intervention can also help temporarily manage symptoms related to the ptosis and dysphagia. Cutting one of the throat muscles internally, an operation called cricopharyngeal myotomy, can be one way to ease symptoms in more severe cases.

Physical therapy and specifically designed exercises may assist with proximal limb weakness, though there is still no current definitive data showing it will stop the progress of the disease. Many of those affected with the proximal limb weakness will eventually require assistive devices such as a wheelchair. As with all surgical procedures, they come with many risk factors. As the dysphagia becomes more severe, patients become malnourished, lose significant weight, become dehydrated and suffer from repeated incidents of aspiration pneumonia. These last two are often the cause of death.

Muscular dystrophy (MD) is a group of muscle diseases that results in increasing weakening and breakdown of skeletal muscles over time. The disorders differ in which muscles are primarily affected, the degree of weakness, how fast they worsen, and when symptoms begin. Many people will eventually become unable to walk. Some types are also associated with problems in other organs.

There are nine main categories of muscular dystrophy that contain more than thirty specific types. The most common type is Duchenne muscular dystrophy (DMD) which typically affects males beginning around the age of four. Other types include Becker muscular dystrophy, facioscapulohumeral muscular dystrophy, and myotonic dystrophy. They are due to mutations in genes that are involved in making muscle proteins. This can occur due to either inheriting the defect from one's parents or the mutation occurring during early development. Disorders may be X-linked recessive, autosomal recessive, or autosomal dominant. Diagnosis often involves blood tests and genetic testing.

There is no cure for muscular dystrophy. Physical therapy, braces, and corrective surgery may help with some symptoms. Assisted ventilation may be required in those with weakness of breathing muscles. Medications used include steroids to slow muscle degeneration, anticonvulsants to control seizures and some muscle activity, and immunosuppressants to delay damage to dying muscle cells. Outcomes depend on the specific type of disorder.

Duchenne muscular dystrophy, which represents about half of all cases of muscular dystrophy, affects about one in 5,000 males at birth. Muscular dystrophy was first described in the 1830s by Charles Bell. The word "dystrophy" is from the Greek "dys", meaning "difficult" and "troph" meaning "nourish". Gene therapy, as a treatment, is in the early stages of study in humans.

The types of Emery–Dreifuss muscular dystrophy are distinguished by their pattern of inheritance: X-linked, autosomal dominant, and autosomal recessive.

- Autosomal dominant "Emery–Dreifuss muscular dystrophy" individuals experience heart problems with weakness (and wasting) of skeletal muscles and Achilles tendon contractures.

- X-linked "Emery–Dreifuss muscular dystrophy" is the result of the EMD gene, with cardiac involvement and some mental retardation.

- Autosomal recessive individuals with this type of the disorder demonstrate cardiac issues, such as arrhythmia. Individuals who acquire EDMD via the autosomal recessive route have an incidence of 1 in 300,000.

The treatment (management) of Emery–Dreifuss muscular dystrophy can be done via several methods, however secondary complications should be consider in terms of the progression of EDMD, therefore cardiac defibrillators may be needed at some point by the affected individual. Other possible forms of management and treatment are the following:

- Orthopaedics

- Surgery

- Monitor/treat any cardiac issues

- Respiratory aid

- Physical therapy

In northern Scandinavia, the prevalence of myotonia congenita has been estimated at 1:10,000.

Myotonia congenita is estimated to affect 1 in 1,000,000 people worldwide.

Currently this sub-type of muscular dystrophy has no cure and no "definitive" treatment exists. Treatment offers preventative tactics to delay muscle breakdown and increase life expectancy. Stretching and physical therapy can increase mobility. Treatment also includes correcting skeletal abnormalities through orthopedic surgery and other orthopedic techniques. Antiepileptic medication is administered to help prevent seizures. ACE inhibitors and beta blockers help treat heart conditions, and respiratory assistance is more than likely needed at some point for the affected individual

In 2007 the FSHD Global Research Foundation was established to increase the amount of funding available to research bodies. The Foundation has identified 13 priority areas of interest for FSHD research.

Distal muscular dystrophy (or distal myopathy) is a group of disorders characterized by onset in the hands or feet. Many types involve dysferlin, but it has been suggested that not all cases do.

Types include:

DYSF is also associated with limb-girdle muscular dystrophy type 2B.

Distal muscular dystrophy is a type of muscular dystrophy that affects the muscles of the extremities, the hands, feet, lower arms, or lower legs. The cause of this dystrophy is very hard to determine because it can be a mutation in any of at least eight genes and not all are known yet. These mutations can be inherited from one parent, autosomal dominant, or from both parents, autosomal recessive. Along with being able to inherit the mutated gene, distal muscular dystrophy has slow progress therefore the patient may not know that they have it until they are in their late 40’s or 50’s. There are eight known types of distal muscular dystrophy. They are Welander’s distal myopathy, Finnish (tibial) distal myopathy, Miyoshi distal myopathy, Nonaka distal myopathy, Gowers–Laing distal myopathy, hereditary inclusion-body myositis type 1, distal myopathy with vocal cord and pharyngeal weakness, and ZASP-related myopathy. All of these affect different regions of the extremities and can show up as early as 5 years of age to as late as 50 years old. Doctors are still trying to determine what causes these mutations along with effective treatments.

Sodium channel myotonias (SCN4A)

- Potassium-aggravated myotonia (acetazolamide responsive myotonia)

- Paramyotonia congenita

- Hyperkalemic periodic paralysis

Dystrophies

- Myotonic dystrophy (myotonic muscular dystrophy: Type 1 and Type 2)

Potassium channel disorders (KCNJ2)

- Andersen-Tawil syndrome

Other disorders

- Thyroid disorders

- Neuromyotonia (Isaacs Syndrome)

- Stiff person syndrome

- Brody myopathy (Brody Disease, Brody's Disease, Brody's Myopathy)

Facioscapulohumeral muscular dystrophy (FSHMD, FSHD or FSH)—originally named Landouzy-Dejerine—is a usually autosomal dominant inherited form of muscular dystrophy (MD) that initially affects the skeletal muscles of the face (facio), scapula (scapulo) and upper arms (humeral). FSHD is the third most common genetic disease of skeletal muscle. Orpha.net lists the prevalence as 4/100,000 while a 2014 population-based study in the Netherlands reported a significantly higher prevalence of 12 in 100,000.

Symptoms may develop in early childhood and are usually noticeable in the teenage years, with 95% of affected individuals manifesting disease by age 20 years. A progressive skeletal muscle weakness usually develops in other areas of the body as well; often the weakness is asymmetrical. Life expectancy can be threatened by respiratory insufficiency, and up to 20% of affected individuals become severely disabled, requiring use of a wheel chair or mobility scooter. In a Dutch study, approximately 1% of patients required (nocturnal or diurnal) ventilatory support. Non-muscular symptoms frequently associated with FSHD include subclinical sensorineural hearing loss and retinal telangiectasia.

In more than 95% of known cases, the disease is associated with contraction of the D4Z4 repeat in the 4q35 subtelomeric region of Chromosome 4. Seminal research published in August 2010 now shows the disease requires a second mechanism, which for the first time provides a unifying theory for its underlying genetics. The second mechanism is a "toxic gain of function" of the DUX4 gene, which is the first time in genetic research that a "dead gene" has been found to "wake up" and cause disease.

Building on the 2010 unified theory of FSHD, researchers in 2014 published the first proposed pathophysiology definition of the disease and four viable therapeutic targets for possible intervention points.