Two different mutations can cause CISS; CRLF1 on chromosome 19 is the most common (90%), it gives CISS type 1 and CLCF1 on chromosome 11 (10%) gives CISS type 2; both types are phenotypically indistinguishable, and they have the same sequence of events [4, 13, 14]. Here, CLCF1 is linked to cold-induced sweating syndrome.