That chorea may sometimes occur as a result of cerebral syphilis has been accepted for some years (Kinnier Wilson 1940) and it has often previously been reported in association with G.P.I. The literature on the topic is dealt with by Lowrey and Smith (1918), Stone and Falstein (1938) and Weickhardt (1945). In all the reports however I can find only three previous instances where clinical and serological evidence of G.P.I. in a patient was associated with a family history and clinical syndrome of Huntington's chorea. These cases were reported by Pagliano and Aviennos (1922), Urechia and Rusdea (1922) and Stone and Falstein (1938) and the case here described appears to be only the fourth similar example to be reported. It has a practical as well as an academic interest since the differential diagnosis of the early stages of Huntington's chorea from those of G.P.I. is still sometimes necessary.