P2X7 polymorphism. Upper panel: The A1513C polymorphism of P2X7 was detected by restriction fragment length polymorphism (RFLP) analysis, as described in the Materials and Methods section. The PCR product was digested with Hha I and run on a 2% agarose gel. First lane, 100 bp marker; lane A, wild-type A/A (223 bp); lane B, heterozygote A/C (134 bp); lane C homozygote C/C (89 bp); last lane, negative control with no DNA added. Lower panel: sequencing analysis of PCR-RFLP products A, B, and C of the upper panel (wt, heterozygote and homozygote, respectively).