Central core disease attacks the skeletal muscles that are used for movement. As a result, people with this disease experience muscle weakness. The affects of this disease range from unnoticeable deficiencies in movement to severe muscle weakness. This inherited neuromuscular disorder is caused by a mutation in the RYR1 gene. It is an uncommon disorder, although the exact incidence of people suffering from the disease is unknown.
Cores, for which the disease is named after, are disorganized areas in the muscle fibers. These areas are only visible under a microscope. The gene responsible for the disorder is the RYR1 gene, which tells the body how to make the protein ryanodine receptor 1. Ryanodine receptors help muscle fibers contract, therefore allowing the body to move properly. A mutated RYR1 gene impairs the proper functioning of the ryanodine receptor and causes muscle weakness.
The most common inheritance pattern for central core disease is autosomal dominant, meaning that one altered gene in each cell can cause the disorder. A person with just one parent affected by the mutated gene can inherit the disease. Fewer numbers of people inherit the disease through an autosomal recessive pattern. This means that both copies of each cell have the mutated gene. An individual who has both parents with a copy of the mutated gene would inherit the disease in this manner.
Doctors have classified the disease as a congenital myopathy. This means it is a muscle disorder that is present at birth. In infants, it initially presents as diminished muscle tone, known as hypotonia, which results in abnormal floppiness. The disorder can delay sitting, crawling, standing, and walking.
People suffering from this disease mostly experience mild muscle weakness that affects the center of the body, most notably the legs and hips. It can also affect facial muscles. People with central core disease may develop spine curvature, hip dislocation, and deformities in the joints. The muscle weakness experienced by people who are affected does not tend to worsen over time.
A muscle biopsy or genetic test can be used to diagnose central core disease. Symptoms of the disease may be clearly visible after birth. There is no central core disease treatment. Instead, patients can typically manage their symptoms through close monitoring by a doctor, physiotherapy sessions, and surgery to correct deformities.
Malignant hyperthermia can affect sufferers of central core disease. It is a severe reaction to certain drugs, such as anesthetic gases, used during surgical procedures. This reaction causes muscle rigidity, high fever, acidosis, rapid heart rate, and the breakdown of muscle fibers. The condition can be life-threatening if it is not treated quickly.