To establish and complete a protocol for genotyping of single polymorphism rs165599 on catechol-O-methyltransferase (COMT) gene by PCR-RFLP. Methods: DNA samples of rs165599 known genotypes by sequencing, using techniques including PCR amplification, restriction fragment length polymorphism, and agarose gel electrophoresis to determine parameters for optimization of the protocol. | Application of PCR-RFLP techinique in genotyping for RS165599 polymorphism on COMT gene