GPIHBP1 and Cowden syndrome 1: In addition among 33 patients with unexplained CS and no genetic mutations, one was found to have GPIHBP1 autoantibodies (18) and in another recent report a patient with newly acquired CS resistant to standard treatment was found to have GPIHBP1 antibodies that disappeared with normalization of HTG after treatment with the anti-B cell monoclonal antibody rituximab (19).