Myasthenia gravis in identical twins

Area of Science:

• Neurology
• Immunology
• Genetics

Background:

• Myasthenia gravis (MG) is an autoimmune disorder affecting neuromuscular junctions.
• Familial occurrence of MG suggests a genetic predisposition.
• Monozygotic twins provide a unique model for studying genetic and environmental factors in disease.

Observation:

• This report details a pair of monozygotic twins diagnosed with myasthenia gravis.
• Monozygosity was confirmed through blood group analysis, HLA typing, and mixed lymphocyte culture.
• Both affected twins exhibited strongly positive acetylcholine receptor antibodies.

Findings:

• The twins demonstrated a poor response to anticholinergic medication and thymectomy.
• Low-dose daily maintenance prednisone was required for both individuals to maintain a normal lifestyle.
• The risk of developing myasthenia gravis is highest in an unaffected monozygotic twin soon after the proband's diagnosis.

Implications:

• This case highlights the role of genetic factors in myasthenia gravis concordance within identical twins.
• Long-term immunosuppressive therapy, such as prednisone, may be necessary for managing severe MG cases.
• Continuous monitoring of unaffected monozygotic twins is crucial due to the ongoing risk of disease development.