Anti-Contactin-1 Nodopathy Presenting With Dysphagia and Nephrotic Syndrome: Remarkable Neurological and Renal...

Although the typical phenotype of anticontactin-1 (CNTN1) nodopathy has been well characterized, dysphagia has received limited attention in the literature. We report a patient with anti-CNTN1 nodopathy presenting with dysphagia and nephrotic syndrome who achieved marked neurological and renal recovery following early B-cell-depleting therapy.

A 77-year-old man with hypertension, dyslipidemia, diabetes mellitus, and pre-existing heavy proteinuria developed rapidly progressive distal numbness, limb weakness, sensory ataxia, mild dysphagia, and functional decline. Neurological examination demonstrated symmetric limb weakness, generalized areflexia, sensory impairment, pseudoathetosis, and ataxia. Nerve conduction studies revealed a demyelinating polyneuropathy, and cerebrospinal fluid analysis showed albuminocytologic dissociation (protein 271 mg/dL). Gadolinium-enhanced brain magnetic resonance imaging was unremarkable despite bulbar symptoms. Anti-CNTN1 antibody testing confirmed autoimmune nodopathy. Treatment with high-dose corticosteroids followed by rituximab (two 1 g infusions) resulted in neurological improvement within 1 month, with complete resolution of dysphagia, restoration of independent ambulation, and progressive functional recovery. The Inflammatory Neuropathy Cause and Treatment (INCAT) disability score improved from 4 to 0 over 7 months. Concurrently, nephrotic-range proteinuria markedly improved, demonstrating parallel neurological and renal recovery.

This case highlights several important features of anti-CNTN1 nodopathy, including neuro-renal coupling, dysphagia as a potentially under-recognized manifestation of bulbar involvement, and an unusually favorable outcome following early B-cell-depleting therapy. Diabetes may complicate recognition of the disorder by mimicking both neuropathic and renal manifestations. Together with the reported association between anti-CNTN1 nodopathy and malignancy, the clinical heterogeneity of this condition underscores the importance of early antibody testing and prompt targeted immunotherapy.