Is Myasthenia Gravis Genetically Inherited?

Myasthenia gravis is not genetically inherited although the risk factor increases if the person has any family member suffering from this condition.

Although the risk of a person with family members suffering from myasthenia gravis is significantly increased, the studies do not prove that myasthenia gravis is genetically inherited. Monozygotic twins are more affected with myasthenia gravis as compared to dizygotic twins. The condition is also not contagious, and the more than one members of the family may be affected. Various genes are studied in the patient suffering from myasthenia gravis and found that there is some association with the gene mutation and myasthenia gravis along with significant association with thymus disorders and rheumatoid arthritis. However, the studies fail to conclude that these gene mutations pass on to the next generation. Further, it is also found that the risk of myasthenia gravis increases if any of the family members have not only myasthenia gravis but may have any of the autoimmune condition indicating that whole of the immune system gets altered. The association was found between the early onset of myasthenia gravis and presence of B8 allele. Human Leucocyte Antigen -DR subtypes are also found to be associated with myasthenia gravis and other autoimmune diseases.

In more than 50% of the patients with ocular myasthenia gravis, HLA-DR1 was found while only about 3% of the patient with generalized myasthenia gravis contains HLA-DR3. Almost 50% of the patients suffering from the concurrent autoimmune disorder have HLA-DR1. Two types of childhood myasthenia gravis occur. The first type is present in the child below 2 years of age and is generally an autosomal recessive condition while the other occurs in between 2 years to 20 years and has the adult symptoms. Studies indicate that siblings are the most commonly affected pair when it comes to the occurrence of the condition in the same family. The mutation occurs in the AChR epsilon-subunit gene of a patient who suffers from congenital myasthenia gravis while antibody testing reveals that both the parents of the patient were negative for autoimmune antibody. ⁽¹⁾

Myasthenia gravis largely affect the muscles of the body especially the muscles of the upper part of the body. It is a progressive condition and if left untreated may lead to serious complications. The unmanaged condition may significantly reduce the quality of life. Very rare, the symptoms may subside without any treatment, but they become active very soon. Following are the symptoms experienced by the patient suffering from myasthenia gravis-

Difficulty Swallowing- Swallowing is generally a muscular process as the muscles of the throat assists in swallowing. Myasthenia gravis makes the throat muscles weak leading to dysphagia. The patient is advised to eat soft food which can be swallowed easily.

Improper Speech- The muscles of the vocal system of the body are also affected due to myasthenia gravis. The patient has poor control over the pitch and tone of the voice and the speech becomes slurred.

Difficulty Walking– As the condition progresses, the muscles of the lower part also get affected. The patient is not able to walk properly and requires the support of others in walking. In severe cases, the patient feels difficulty in standing.

Emotional Stress– Due to widespread body pain and social isolation the patient is under tremendous emotional stress. The patient may feel anxiety, depression, and frustration which further worsen the condition.

Respiratory Problems- The muscles of the respiratory system such as chest muscles and the diaphragm become weak due to myasthenia gravis and are not able to relax and contract. This causes breathing problems in the patient. ⁽²⁾

Various studies have conducted to analyze the genetic inheritance of myasthenia gravis but none of them concludes that myasthenia gravis is a genetically inherited. In some studies, it has been found that siblings are most commonly affected as compared to other family members of the family.

References

1. https://www.omim.org/entry/254200
2. https://rarediseases.org/rare-diseases/myasthenia-gravis/

Also Read:

• Myasthenia Gravis: Causes, Signs, Symptoms, Investigations, Treatment- Medications, Surgery
• How Do You Get Myasthenia Gravis?
• Can Myasthenia Gravis Go Away On Its Own?
• Recovery Period For Myasthenia Gravis
• What Is The Best Treatment For Myasthenia Gravis?
• Does Thymectomy Cure Myasthenia Gravis?
• What Is The Difference Between MS ALS And Myasthenia Gravis?