Distinct patterns of small-fiber dysfunction in anti-MAG-positive and anti-MAG-negative IgM paraproteinemic neuropathies

This dataset contains anonymized clinical, neurophysiological, quantitative sensory testing (QST), laboratory, and longitudinal follow-up data from patients with IgM paraproteinemic neuropathy and healthy volunteers. The dataset was generated within a prospective observational study aimed at characterizing small-fiber dysfunction in IgM paraproteinemic neuropathies, comparing anti-myelin-associated glycoprotein (MAG)-positive and anti-MAG-negative patients, and exploring relationships with nerve conduction studies (NCS), disability, quality of life, and serum neurofilament light chain (NfL). Participants include: • 39 patients with IgM paraproteinemic neuropathy o 24 anti-MAG-positive o 15 anti-MAG-negative • 20 age- and sex-matched healthy volunteers Thermal QST was performed at hand and foot and included: • Warm Detection Threshold (WDT) • Cold Detection Threshold (CDT) • Heat Pain Threshold at VAS 50-60 (Pain50-60) Clinical assessments comprised validated disability and sensory scales (INCAT sensory sum score, ONLS, I-RODS), neuropathic pain intensity, and health-related quality of life (EuroQoL-5D and EQ-VAS). Electrophysiological data include detailed motor and sensory nerve conduction parameters, terminal latency index (TLI), F-wave latencies, and classification of neuropathy phenotype (demyelinating vs axonal). Laboratory data include anti-MAG antibody titers and serum neurofilament light chain (NfL) concentrations. A 12-month longitudinal reassessment (clinical, QST, and electrophysiology) is available for a subgroup of patients. All data are fully anonymized. No directly identifiable personal information is included.