What is seronegative myasthenia gravis and how common is it?
Seronegative MG is a rare form affecting about 10% of people with myasthenia gravis. It occurs when blood tests don't show the typical antibodies (AChR or MuSK) that are usually present in MG, even though symptoms match an MG diagnosis.
Common symptoms include Show Full Answer
What is seronegative myasthenia gravis and how common is it?
Seronegative MG is a rare form affecting about 10% of people with myasthenia gravis. It occurs when blood tests don't show the typical antibodies (AChR or MuSK) that are usually present in MG, even though symptoms match an MG diagnosis.
Common symptoms include:
• Droopy eyelids
• Blurry or double vision
• Changes in facial expressions
• Muscle weakness
• Difficulty breathing
• Trouble talking
• Problems with swallowing or chewing Who typically gets seronegative MG?
This form tends to:
• Affect younger people including young adults and children
• Be more common in females
• Present with milder symptoms
• More frequently affect eyes and bulbar muscles (causing vision, speaking, and swallowing issues)
• Have a lower risk of thymus tumors
Newer testing methods like cell-based assays are showing that some people initially diagnosed as seronegative may actually have very low levels of the typical antibodies that weren't detected by older tests.
September 22, 2025
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