If you have a close relative with Myasthenia Gravis (MG), you run a greater risk than the average population of being diagnosed with it. Additionally, you have a greater risk of developing several other autoimmune diseases if you have a first-degree relative with MG. First-degree relatives include your parents, siblings and children.
MG is a rare autoimmune disease affecting fewer than 200,000 patients annually in the United States. A patient with MG will experience muscle weakness in the arms and legs. Breathing may get more difficult as this neuromuscular disease attacks the muscles responsible for respiration. Symptoms of MG might include: drooping eye lid, shortness of breath, problems swallowing and weakness in the extremities, among other symptoms.
The genetic connection was reported in this Taiwanese study in the journal Clinical Epidemiology. Typically, it was assumed MG development was a combination of genetic and environmental factors. There are not too many studies like this one, that attempt to quantify the genetic part of the equation without consideration of the environmental.
The researchers used a Taiwanese insurance database that included over 12 million individuals with 15,066 who had at least one first-degree family member with MG. 8,638 of the individuals were a parent–child relationship, 3,279 individuals had a child that was diagnosed, 3,134 had brothers or sisters that had MG and 26 cases were with twins.
The researchers concluded that having a family member with MG made a person a higher risk for development of the autoimmune neuromuscular disease.
“This nationwide family study confirms that an MG family history is associated with a high risk for the disease. Differential risk associated with different kinships suggests a strong genetic component in MG susceptibility.” — study authors
Patient’s relatives were 7.78 times more likely to have MG than the general population and siblings had the highest likelihood of all the first-degree relatives were siblings who were more than 17.85 times more likely to have MG than the general population. From the data, authors also calculate MG susceptibility is 82.1% attributed to genetic factors and 17.9% to non-shared environmental factors.
By shedding light on the genetic component of Myasthenia Gravis, researchers hope that one day there will be more advanced MG risk studies as well as help in improving educating and advising patients of MG and their families.