Spontaneous HIT (S-HIT) is an even less frequent variant of HIT, with only a handful of reports available in the literature, where unexplained thrombocytopenia and/or thrombosis without recent heparin exposure occurs and anti-PF4 antibodies of the immunoglobulin G (IgG) subclass are strongly positive [4]. This evidence concerns the gene PF4 and Thrombocytopenia.