[Multifocal motor neuropathy. Report of three cases at a reference hospital in Mexico].

Background: Motor multifocal neuropathy is an immunemediated neuropathy characterized by progressive and asymmetric weakness of the distal extremities, without sensory symptoms, and an important feature of conduction blocks. The objective of this study is to comprehensively describe the nosological and pathogenic implications of this neurodegenerative disorder, given the unclear diagnosis of MMN and the significant challenges it poses. Clinical cases: We present three clinical cases with a chronic clinical presentation, in which neuroconduction studies were performed, revealing the presence of anti-IgM GM1 antibodies, consistent with the diagnosis of motor multifocal neuropathy. Although the treatment administered in these cases was successful, it is important to note that the diagnosis of MMN experienced some delay, emphasizing the need for greater awareness and understanding of this disease. Conclusion: The diagnosis of motor multifocal neuropathy is often delayed, and an incorrect treatment can worsen symptoms, especially due to its similarity to other neuropathies and nerve and muscle diseases. Despite a generally favorable prognosis, the lack of early diagnosis can lead to severe motor sequelae. In this study, we provide detailed descriptions of three clinical cases from a reference center in Mexico, presenting their clinical manifestations, observed neurophysiological patterns, and treatment response.