Considering the photo-thrombotic action of PDT-V on CNV45–49, a comprehensive appraisal of the thrombophilic predisposition of vascular endothelium induced by MTHFR-C677T-related hyperhomocysteinemia (HHcy) provides explanation about the rationale of this pharmacogenetic correlation62–64. This evidence concerns the gene MTHFR and hyperhomocysteinemia.