CD209 and tick-borne encephalitis: Notably, the physiologically relevant functional importance of DC-SIGN in flavivirus replication and pathogenesis in humans is underlined by the association of a single nucleotide polymorphism (SNP) found in the promoter region of the DC-SIGN gene with a greater susceptibility to dengue hemorrhagic fever (SNP rs4804803 [333]) and severe forms of tick-borne encephalitis (SNP rs2287886 [334]) in certain subpopulations.