Jornal de Genômica Clínica e Médica

Evaluation of ApoE Genotyping Using Saliva-Derived DNA

Abstract

Takuya Kushioka, Makoto Ocho, Yukihiko Ito, Takafumi Yokokawa, Kei Yui and Yoshimitsu Yamasaki

Background: The single nucleotide polymorphism (SNP) regions (rs429358 and rs7412) that define the ApoE genotype have a high GC content, which makes genotyping difficult. Blood samples are mainly used for ApoE genotyping, and saliva has also been used in recent years. However, the equivalency of genotyping results using saliva samples has not been verified. Hence, we evaluated the equivalency of the genotyping results for saliva samples by two genotyping methods such as Sanger sequencing and restriction fragment length polymorphism (RFLP).
Methods: Saliva and blood samples were collected from 51 subjects. The yield and quality of the extracted DNA were assessed. The regions around ApoE SNP were amplified by PCR, and genotyping was performed by Sanger sequencing and RFLP.
Results: The mean concentration of saliva-derived genomic DNA was lesser than that of blood-derived DNA, and the quality of many saliva-derived DNA samples was poor. Regarding genotyping, the results of saliva-derived genomic DNA were 100% consistent with those of blood-derived DNA. Also, the results were 100% consistent between the two methods.
Conclusion: Although the mean concentration of saliva-derived genomic DNA was lower than that of blood-derived DNA, and the variation in the quality of saliva-derived genomic DNA was higher than that of blood-derived DNA, the APOE genotyping results were equivalent for both the samples.