DEFB1 and Sepsis: The majority of the defensin genes including DEFB1, DEFB4 and DEFB103 encoding human beta-defensins 1, 2 and −3, respectively [13], are located on chromosome 8p23.1, a region of great complexity with both functional SNPs (DEFB1) and copy number variation (CNV) of a wide range of beta-defensin genes including DEFB4 and DEFB103. DEFB1 is apparently constitutively expressed [14], but functional single nucleotide polymorphisms (SNPs) in DEFB1 have been associated with susceptibility to severe sepsis [15].