The following information may help to address your question:
What is Brody myopathy?
Brody myopathy is a hereditary condition that affects the skeletal muscles (muscles used for movement). Symptoms typically begin in childhood and are characterized by muscle cramping and stiffening (myopathy) after exercise or other strenuous activity. These symptoms can worsen in cold temperatures and are usually painless, however, some individuals may have mild discomfort.
[1][2] Some cases of Brody myopathy are caused by
mutations in the
ATP2A1 gene. The cause of Brody myopathy for individuals not found to have an
ATP2A1 gene mutation remains unknown. Brody myopathy is usually
inherited in an
autosomal recessive manner with a few reported cases of
autosomal dominant inheritance.
[1][2][3] While there is no one treatment for Brody myopathy, certain muscle relaxants, such as
dantrolene and blood pressure medications called calcium channel blockers, such as
verapamil may be useful.
[3]
Some researchers suggest that individuals found to have an
ATP2A1 gene mutation have a slightly different disorder in which symptoms appear at an earlier age. They use the disease term "Brody disease" for individuals with an identified mutation versus "Brody
syndrome" for those that do not.
[1][4] More research may help clarify whether these are two different disorders or a variation of the same disorder.
Last updated: 7/29/2016
What are the symptoms of Brody myopathy?
Symptoms of Brody myopathy typically begin in childhood. Children with this condition may have a hard time keeping up with their peers in physical activities. They have a difficult time relaxing muscles, first in their arms and legs, but then in their face and trunk. They may also have difficulty relaxing their eyelids and grip. These muscle symptoms worsen with exercise and exposure to cold weather.
[5]
In people with Brody myopathy, the term “pseudomyotonia” is used to describe these muscle symptoms. The term “myotonia” refers to muscle stiffness or an inability to relax the muscles and can be evidenced by abnormal
electromyography (EMG) results. In Brody myopathy, the EMG results are normal, even though the person show signs of the muscle stiffness. Because of the normal EMG results, the word “pseudo-myotonia” is used.
[5]
Individuals with Brody myopathy sometimes develop myoglobinuria. Myoglobinuria occurs when exercise leads to the breakdown of muscle
tissue and release of a
protein called myoglobin into the urine. Myoglobin causes the urine to be red or brown.
[2]
Last updated: 8/3/2016
What causes Brody myopathy?
Brody myopathy can be caused by
mutations in the gene
ATP2A1 gene
. This gene provides instructions for making an
enzyme called sarco(endo)plasmic reticulum calcium-ATPase 1 (SERCA1). Enzymes are proteins that accelerate chemical reactions within the body. The SERCA1 enzyme is found in skeletal muscles (muscles used for movement). It is involved in moving calcium around in the
cell, which is important for normal muscle contraction. Mutations in the
ATP2A1 gene results in problems with calcium transportation in the cell, and ultimately problems with muscle contraction.
[6]
Not all people with Brody myopathy have mutations in the
ATP2A1 gene. There are likely other gene mutations, that have not yet been identified, that can cause this disease.
[2]
Last updated: 8/3/2016
How is Brody myopathy inherited?
Most cases of Brody myopathy are inherited in an
autosomal recessive manner.
[2] This means that to have the condition, a person must have a
mutation in both copies of the responsible
gene in each cell. People with Brody myopathy inherit one mutated copy of the gene from each parent, who is referred to as a
carrier. Carriers of an autosomal recessive condition typically do not have any signs or symptoms (they are unaffected). When 2 carriers of an autosomal recessive condition have children, each child has a:
- 25% (1 in 4) chance to be affected
- 50% (1 in 2) chance to be an unaffected carrier like each parent
- 25% (1 in 4) chance to be unaffected and not be a carrier
Last updated: 8/3/2016
How rare is Brody myopathy?
Brody myopathy is estimated to occur in 1 out of 10,000,000 people. Researchers suggest that this may be an underestimation as the diagnosis may go unrecognized.
[1][7]
Last updated: 8/3/2016
How is Brody myopathy diagnosed?
Brody myopathy is suspected in people with the characteristic symptoms. The diagnosis may be confirmed using a combination of several different evaluations including:
[5][1]
- Physical examination
- Bloodwork to evaluate the level of certain proteins such as creatine kinase
- Muscle biopsy
- Electromyography
Last updated: 8/3/2016
How might Brody myopathy be treated?
There is no one treatment for Brody myopathy. Certain muscle relaxants, such as
dantrolene and blood pressure medications called calcium channel blockers, such as
verapamil have been used with varying levels of success.
[5][3]
Last updated: 8/3/2016
What is the long-term outlook for Brody myopathy?
Symptoms of Brody myopathy may remain the same or slowly worsen with time. In advanced disease some people may experience some muscle loss (atrophy) and weakness.
[5]
Last updated: 8/3/2016
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