Fig. 1

Schematic diagram of the human APOE gene and APOE genotyping method. a The APOE gene is located on chromosome 19, and is polymorphic at two single nucleotides (rs429358 and rs7412) resulting in three different alleles (ε2, ε3 and ε4). b Amplifications of the APOE ε2, ε3 and ε4 alleles are initiated by allele-specific PCR primers. One double-dye oligonucleotide TaqMan probe was included in all reactions to monitor real-time DNA amplification products