Clinical and laboratory features of juvenile-onset anti-NF155 autoimmune nodopathy

Background Neurofascin 155 autoimmune nodopathy (NF155 AN) is a recently recognised immune-mediated neuropathy distinct from chronic inflammatory demyelinating polyneuropathy. While adult-onset cases have been increasingly reported, the juvenile-onset form remains poorly characterised. Methods We retrospectively analysed 36 patients with NF155 AN, focusing on detailed characterisation of 16 juvenile-onset cases. Their clinical and laboratory data were reviewed. Results Juvenile-onset patients presented with sensorimotor neuropathy characterised by distal predominant weakness, tremor and sensory ataxia. Motor symptoms were the presenting feature in 75% of patients, which significantly differed from the adult cases (p=0.0015). Postural tremor was more frequent in juvenile patients (94%), while cranial nerve involvement was less common (19%). Electrophysiologically, absent compound muscle action potentials in lower limbs were significantly more prevalent in juvenile patients (peroneal: 78%; tibial: 66%; p<0.001 for both). Symmetrical spinal root/plexus hypertrophy on MR neurography and characteristic pathological findings were observed in both groups. Intravenous immunoglobulin response was generally poor, while delayed rituximab initiation still led to clinical improvement in the juvenile-onset group. Juvenile patients showed trends towards better functional outcomes. Conclusions Juvenile-onset NF155 AN is distinguished by motor-predominant onset, frequent tremor and characteristic electrophysiological abnormalities, yet demonstrates favourable prognosis with B-cell targeted therapy. Early recognition and timely diagnosis are essential for optimal outcomes.