CNTNAP1 and Ataxia: Soon after admission, the presence of tremor and ataxia prompts testing for IgG antibodies against CASPR1/contactin-1 complex, which come out positive, allowing for a diagnosis of paranodopathy instead of CIDP. Following failure of intravenous immunoglobulin, he receives rituximab (instead of intravenous steroids or plasma exchange) and presents good recovery of respiratory and motor function (requires some help for usual activities, but is able to walk unassisted at discharge).