CNTNAP2 and Isaacs syndrome: In contrast, patients with LGI1 or CASPR2 antibodies often have clinically-indistinguishable late-onset forms of limbic encephalitis and neuromyotonia with associated dysautonomia, sleep disturbances, pain and seizures (Irani et al., 2010; Lai et al., 2010; Klein et al., 2013; Gadoth et al., 2017).