An enzyme, such as Glucose-6-phosphate dehydrogenase (G6PD) could play a role [15] as its X-linked gene locus is at Xq28 and it has a great multiplicity of alleles that are associated in their deficiency with nonspherocytic hemolytic anemia [17], and anemia is a likely risk factor for SIDS [18]. This evidence concerns the gene G6PD and anemia (phenotype).