Expanded phenotypes and outcomes among 256 LGI1/CASPR2 ‐IgG–positive patients

ObjectiveTo describe an expanded phenotypic spectrum and longitudinal outcome in 256 LGI1‐IgG–seropositive and/or CASPR2‐IgG–seropositive patients. MethodsPatients were identified through service neural autoantibody evaluation. Ninety‐five had longitudinal follow‐up (7–456 months; median = 35). ResultsAmong 3,910 patients tested, 196 were LGI1‐IgG positive, 51 were CASPR2‐IgG positive, and 9 were dual positive. Cerebrospinal fluid testing was less sensitive than serum testing, detecting only 24 of 38 (63%) LGI1‐IgG–positive and 5 of 6 (83%) CASPR2‐IgG–positive patients. LGI1‐IgG–positive specimens had higher voltage‐gated potassium channel–IgG immunoprecipitation values (0.33nmol/l, range = 0.02–5.14) than CASPR2‐IgG–positive specimens (0.10nmol/l, range = 0.00–0.45, p < 0.001). Of patients presenting with pain or peripheral nervous system (PNS) manifestations, 39% were LGI1‐IgG seropositive (7% had solely neuropathy or pain). Multivariate analysis identified age as the only significant predictor of central nervous system (CNS) versus PNS involvement (>50 years; odds ratio = 15, p < 0.001). Paroxysmal dizziness spells (PDS), a unique LGI1‐IgG accompaniment (14% of patients), frequently delayed the diagnosis. T2‐mesiotemporal hyperintensity was more common in LGI1‐IgG–positive (41%) than in CASPR2‐IgG–positive patients (p = 0.033). T1‐bright basal ganglia were confined to LGI1‐IgG–positive patients with fac...
Source: Annals of Neurology - Category: Neurology Authors: Tags: Research Article Source Type: research