Paramyotonia Congenita (PMC)
What is Paramyotonia Congenita (PMC)?
Paramyotonia congenital (PMC) is a disorder that affects muscles used for movement (skeletal muscles). Beginning in infancy or early childhood, people with this condition experience bouts of sustained muscle tensing (myotonia) that prevent muscles from relaxing normally. Myotonia causes muscle stiffness that typically appears after exercise and can be induced by muscle cooling. This stiffness chiefly affects muscles in the face, neck, arms, and hands, although it can also affect muscles used for breathing and muscles in the lower body. Unlike many other forms of myotonia, the muscle stiffness associated with paramyotonia congenita tends to worsen with repeated movements. More information about PMC may be found on the NIH’s website: https://medlineplus.gov/genetics/condition/paramyotonia-congenita/
What is the prevalence of Paramyotonia Congenita (PMC)?
Paramyotonia congenita (PMC) is an uncommon disorder; it is estimated to affect fewer than 1 in 100,000 people.
How is Paramyotonia Congenita (PMC) diagnosed?
When PMC is suspected, a test is administered to test the capacity of muscles to conduct electricity (electromyography). During the test, the muscles are chilled and electrical signals are recorded before and after the muscle is cooled. The electromyography (EMG) will show rapid repetitive electrical discharges. EMG cannot always diagnose PMC definitively, and further testing may be necessary. Genetic testing on a blood sample will result in a definitive diagnosis by showing the presence of a characteristic mutation in the SCN4A gene. More information about diagnosis of PLS may be found on NORD’s website: https://rarediseases.org/rare-diseases/paramyotonia-congenita/
Is there any specific gene/pathway in Paramyotonia Congenita (PMC) that has been identified?
Paramyotonia congenita (PMC) is an autosomal dominant genetic condition caused by a mutation in the muscle sodium channel gene SCN4A.
How is Paramyotonia Congenita (PMC) treated?
The aim of treatment of Paramyotonia congenita (PMC) is to reduce the intensity of acute symptoms and to prevent, as far as possible, further attacks. Some attacks are so mild that treatment is not necessary. However, in other instances drug therapy is required. Treatment with medications that block the sodium channels such as mexiletine and lamotrigine may help reduce the stiffness related to myotonia.
Are there any clinical trials underway for Paramyotonia Congenita (PMC)?
The National Institutes of Health (NIH) has completed 6 clinical trials for PMC. Currently, there are 0 clinical trials underway for the condition. More information on future studies and patient recruitment can be found here: https://clinicaltrials.gov/ct2/results?cond=Paramyotonia+Congenita+&term=&cntry=&state=&city=&dist=
How can RareShare be helpful to Paramyotonia Congenita (PMC) patients and families?
The Paramyotonia congenita (PMC) Rareshare community has 5 members. There is currently 1 active discussion underway. New discussions can help to connect patients, health workers, caregivers and families interested in PMC and provide them continual access to community resources.