Clinical Profile, Electrophysiology, and Short-Term Outcomes of Pediatric-Onset Autoimmune Nodopathy-A Case Series.

BACKGROUND: Autoimmune nodopathies (ANs) are characterized by antibodies targeting nodal and paranodal proteins. Among AN, antibodies targeting neurofascin 186 and/or 140 are rarely reported in children. We describe the clinical features, electrophysiology, histopathology, and treatment outcomes of three children with anti-NF186/140 AN and isolated anti-NF140 AN. METHODS: Retrospective case series. RESULTS: Case 1 was 13-year boy with nephrotic syndrome presented with acute onset asymmetric progressive sensorimotor polyneuropathy with anti-NF140 antibody-positive AN. Cases 2 was a 7.6-year girl with chronic progressive symmetric distal weakness, subacute worsening, and had combined anti-NF186/140 antibody-positive AN. Case 3 was a 3.5-year-old boy with chronic progressive symmetric distal dominant weakness of all four limbs and had bulbar involvement with anti-NF140 antibody-positive AN. All three children had bilateral upper limb tremors. Electrophysiology demonstrated a non-length-dependent mixed axonal and demyelinating pattern of sensorimotor polyneuropathy. Nerve biopsy revealed axonal and mild myelin loss in all three cases, with lymphocytic infiltration in case 1. Treatment included steroids, intravenous immunoglobulins, plasma exchange, cyclophosphamide, and rituximab with graded response and improvement in the Inflammatory Neuropathy Cause and Treatment (INCAT) disability scores. CONCLUSIONS: This case series expands the clinical spectrum of pediatric-onset anti-NF186/140 AN and isolated anti-NF140 AN. Recognition of key clinical clues, including tremors, bulbar involvement, and subacute progression, is essential to distinguish it from chronic inflammatory demyelinating polyneuropathy and Charcot-Marie-Tooth disease to facilitate timely antibody testing and targeted therapy.