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Duchenne Muscular Dystrophy
Duchenne muscular dystrophy (DMD) is a type of muscular dystrophy that affects mostly males with an incidence of about 1 in every 3500. It has the highest incidence rates out of all types of muscular dystrophies and also has some of the most severe symptoms. The symptoms may start presenting from birth or early childhood. Due to the atrophy of muscles, the patient will experiment some difficulty walking, climbing stairs, and its knees and hips will be weakened. The patient will also experience a certain extent of mental deterioration with approximately 20% of patients with DMD have an intellectual quotient (IQ) below 70. The muscle weakness progresses over the years leading to loss of ambulance and eventual death around the age of 20. The most common cause of death is cardiac arrest.

Muscular Dystrophies
Muscular dystrophies can be categorized by the intensity of muscle debilitation and are divided into seven different categories

Congenital Muscular dystrophy
Congenital muscular dystrophy (CMD) manifests at birth or when the baby is approximately six years old. Patients present hypotonia, joint contractures and general weakness. Some other common symptoms include respiratory insufficiency, rigid spine, distal joint laxity, and muscle hypertrophy. In some cases the central nervous system (CNS) is compromised affecting the brain stem, cortex, and cerebellum. This can lead to mental deficiency and eventually epilepsy. Some variants of CMD can cause eye problems. A large percentage of children affected by CMD cannot walk by themselves, some can maintain an upright position with the aid of a physical support structure.

The most common form of CMD is Fukuyama congenital muscular dystrophy and occurs mainly in Japan. CMD is caused by a recessive founder mutation associated with the fukutin gene, the function of which remains unclear. Dr. Yukio Fukuyama was the first to describe this disease in 1960 in Tokyo, Japan.

Duchenne and Becker muscular dystrophy
Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD) present with similar symptoms with the former having an earlier onset of symptoms and being the more severe of the two. The incidence rate of DMD is of 1 per 3500 males, making it the most common type of muscular dystrophy. BMD has an incidence of 1 per 17500 males, it is the least common muscular dystrophy.

Patients suffering from DMD will usually present symptoms in early childhood. At this stage, symptoms may include difficulties walking and climbing stairs, and weakened hips and knees. A certain extent of mental deterioration may occur, with approximately 20% of children obtaining an intelligence quotient (IQ) score bellow 70. Over the years, muscle weakness progresses and around the age of 12 the child with DMD will have lost the capacity to ambulate by himself, requiring the use of a wheelchair. Patients diagnosed with DMD usually begin presenting cardiac problems in their adolescence and young adulthood. The life expectancy for persons affected with DMD is around 20 years with the most common cause of death being cardiac attack.

BMD patients present similar symptoms as those with DMD but with a lower intensity and at a later age. Some BMD patients may lose the ability to walk in their mid-teen years, but some maintain this ability into their adult years. Cardiac muscle is also affected but slower and less severely than in the case of DMD giving BMD patients a life expectancy between 50 and 60 years.

Emery-Dreifuss muscular dystrophy
Emery-Dreifuss muscular dystrophy is caused by a mutation in the STA gene at Xq28 which codes emerin, a protein necessary in the nuclear membrane. This mutation leads to the complete absence of emerin in the muscles. There are a series of symptoms presented with this disorder, including: weakness of the Achilles tendons, posterior cervical muscles and rigidity in the elbows. Later symptoms include restriction of neck flexion and entire spine. As the disease advances limb-girdle muscles deteriorate and weaken. Around the age of thirty the patient may start to develop cardiomyopathy which can lead to a sudden death.