CNTNAP2 and Morvan syndrome: A summary of the core features in 46 double-positive patients reported in the literature (table 1) suggests these patients display clinical features associated with both antigenic targets, often with greater weighting towards those more prevalent in CASPR2 antibody disease (figure 1) and a frequent association with an underlying tumour, particularly thymoma.8 13 Whether this represents a clue to underlying mechanisms, or reflects reporting bias in the literature towards unusual presentations such as autoimmune neuropathy or Morvan’s syndrome,8 13 remains to be determined.