RESUMO
BACKGROUND: ABO genotyping is being used increasingly when the results of serologic typing are unclear or there is some suspicion of rare ABO subtypes. Conventional molecular diagnostic methods such as PCR- restriction fragment length polymorphism (PCR-RFLP), allele-specific PCR, PCR-single stranded conformational polymorphism (PCR-SSCP) and sequence-based typing have been used in this field. Recently, a pyrosequencing technique was introduced into clinical laboratories. This study evaluated the possibility of applying pyrosequencing to ABO genotyping. METHODS: A total of 36 samples, which had previously been analyzed by PCR-RFLP and serological method in the Blood Genetics Clinic of Seoul National University Hospital between August 2001 and September 2004 and shown to have the A/A, A/B, A/O, B/B, B/O, O/O, cis-AB/O, cis-AB/A, or cis-AB/B genotypes, were analyzed by pyrosequencing analysis. Briefly, two PCR reactions were carried out separately for one region including nucleotide 261, and for another region including nucleotides 796 and 803. Pyrosequencing was then performed, and the pyrograms were interpreted using an automated interpretation program from the manufacturer and by researchers independently to determine the nucleotides 261, 796 and 803 for ABO genotyping. RESULTS: The ABO genotypes from pyrosequencing and the interpretation of the pyrograms according to the researcher on 36 samples were in complete concordance with the results obtained by PCR-RFLP. The ABO genotypes from the automated interpretation program showed an error in one out of total 108 SNP (single nucleotide polymorphism) analyses (eRROR RATE=0.9%) OF 36 SAMPLES. CONCLUSION: ABO genotyping for A, B, O, cis-AB alleles by pyrosequencing of nucleotides 261, 796 and 803 was relatively simple and accurate and could be an another field we can use in clinical laboratories.