Synonyms: MADSAM | Multifocal acquired demyelinating sensory and motor neuropathy
Lewis-Sumner syndrome (LSS) is a rare acquired demyelinating polyneuropathy characterized by asymmetrical distal weakness of the upper or lower extremities and motor dysfunction with adult onset. It is considered to be a variant of chronic inflammatory demyelinating polyneuropathy.
Data from Orphanet are used to provide information on a disease's name, synonym(s), and overview. Reference: Access aggregated data from Orphanet at Orphadata. Orphadata: Free access data from Orphanet. © INSERM 1999. Available on http://www.orphadata.org. Data version May 2026
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Lewis-Sumner syndrome?
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Advocacy Organizations
The MOGAD Initiative for Navigation and Direction (MIND)
Many families in the world are currently diagnosed with myelin oligodendrocyte glycoprotein antibody disease (MOGAD). Being diagnosed with a rare disease such as MOGAD can be challenging, especially if you don't know much about it. MIND transforms complex medical terminology to easy-to-understand information for patients/families, leaving no MOGAD patient in the dark about their diagnosis.
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Clinical Trials
For a list of clinical trials in this disease area, please click here.