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The ‐521C/T single nucleotide polymorphism (SNP) in the promoter region of the dopamine D4 receptor gene (DRD4) has recently been detected in oriental (Japanese) individuals and related to novelty seeking and schizophrenia. Here, we report the analysis of the ‐521C/T polymorphism in a Caucasian (Hungarian) population using two independent genotyping methods. The polymerase chain reaction‐restriction fragment length polymorphism (PCR‐RFLP) procedure utilized the FspI restriction site around the ‐521 position. An additional, nonpolymorphic cleavage site was also included into the amplified region to serve as an internal standard for verifying the completion of the digestion. As another independent method, a tetraprimer system for single‐tube allele‐specific PCR (SAS‐PCR) was developed to generate ‐521C and ‐521T specific PCR products with different fragment sizes. Consequently …