Genetic Polymorphism Analysis in Blood

Peripheral blood sample was drawn to examine gene polymorphisms. All the patients’ genomic DNA was extracted from 200 µl of blood sample in EDTA by using a DNA extraction kit (FAVORGEN, Ping-Tung, Taiwan). Polymerase chain reactions (PCRs), PCR-restriction fragment length polymorphisms (RFLPs), or direct sequencing were performed to identify polymorphisms of TPH1 rs211105 (11:g.18033757T>G) located within intron 3, rs4537731 (11:g.18047335A>G) located within the promoter region at –1066, insertion/deletion polymorphisms in 5-HTTLPR, and VNTR counts in 5-HTT, as previously reported.^{(24 (link))} The specimens for direct sequencing were run on an Applied Biosystems 3130xl Genetic Analyzer (Applied Biosystems, Invitrogen Life Technologies, Carlsbad, CA), conforming with the manufacturer’s recommendations.