Clinical phenotypes according to anti-MAG antibody titre and EDX features
| Findings, n (%) | Patients (n=202) | Anti-MAG titre<10 000 BTU (n=22) | Anti-MAG titre≥10 000 BTU (n=180) | Non-definite demyelinating neuropathy (n=32) |
| ‘Typical’ clinical phenotype | 168 (83.2) | 21 (95.5) | 147 (81.7) | 27 |
| Sensory ataxic distal PNP | 51 (25.2) | 6 (27.3) | 45 (25) | 8(5*, 2†, 1‡) |
| Sensory ataxic distal PNP with tremor | 31 (15.3) | 4 (18.2) | 27 (15) | 1* |
| Sensory ataxic distal PNP with progressive distal motor deficit | 53 (26.2) | 5 (22.7) | 48 (26.7) | 10* |
| ‘Variant’ clinical phenotype | ||||
| Non-ataxic sensory PNP | 20 (9.9) | 2 (9) | 18 (10) | 4 (2*, 1†, 1§) |
| Asymptomatic/paucisymptomatic sensory PNP | 11 (5.4) | 0+4 (18.2) | 3+4 (3.9) | 3(1*, 1†, 1‡) |
| Non-ataxic sensorimotor PNP | 2 (1) | 0 | 2 (1.1) | 1(1*) |
| ‘Atypical’ clinical phenotype | 34 (16.8) | 1 (0.5) | 33 (18.3) | 5 |
| Chronic sensorimotor PRN | 22 (10.9) | 1 | 21 (11.7) | 4(2¶, 1*, 1†) |
| Asymmetric and/or multifocal NP | 6 (3) | 0 | 6 (3.3) | 0 |
| Acute sensory/sensorimotor PRN | 4 (2) | 0 | 4 (2.2) | 0 |
| Suggestive of small fibre NP | 1 (0.5) | 0 | 1 (0.6) | 1** |
| Amyotrophic lateral sclerosis and sensory PNP | 1 (0.5) | 0 | 1 (0.6) | 0 |
Statistical analysis did not show significant difference between the two clinical groups according to anti-MAG antibody titres.
EDX features
*Abolished or extremely reduced CMAPs in LL and prolonged distal median motor latencies.
†Axonal sensorimotor neuropathy pattern.
‡Normal or nearly normal conduction parameters.
§Purely prolonged distal median motor latencies with reduced SNAPs.
¶Abolished CMAP in all limb nerves.
**Purely prolonged distal median motor latencies with normal SNAPs in LL.
BTU, Bühlmann Titre Units; CMAP, compound muscle action potential; EDX, electrodiagnostic; LL, lower limbs; MAG, myelin-associated glycoprotein; NP, neuropathy; PNP, polyneuropathy; PRN, polyradiculoneuropathy; SNAP, sensory nerve action potential.