CYP2D6 allele frequencies and copy number variants in Chinese Han population: a large retrospective study

Objectives This study aims to disclose the distribution characteristics of CYP2D6 polymorphisms among the Han population and provide essential data to support the future development of pharmacogenomics. Methods This study retrospectively analyzed the genetic data of 6,964 patients with mental disorders who received CYP2D6 gene testing at the First Hospital of Hebei Medical University from March 2021 to August 2024.The initial phase of the experiment entailed the genotyping and copy number determination of CYP2D6, which were performed, respectively, using an Agena MassARRAY Assay and target-specific TaqMan® real-time quantitative polymerase chain reaction (qPCR) Assays. Results Among the 6,964 Han Chinese patients, the allele frequency of *10 was the highest (65.84%), followed by *36 (39.10%) and *5 (8.26%). In the phenotype distribution, the proportion of normal metabolizers (NM) was the highest (60.20%), followed by intermediate metabolizers (IM, 38.31%), while ultrarapid metabolizers (UM, 0.86%) and poor metabolizers (PM, 0.63%) were relatively less. The proportion of complete deletion of the CYP2D6 gene was 0.57%, the proportion of single copy was 13.96%, the proportion of double copy was 83.41%, and the proportion of triple or more copies was 2.31%. Conclusions The occurrence of CYP2D6 Copy number variations (CNVs) in the Han Chinese population was comprehensively analyzed in this study, and provide essential data to support the future development of pharmacogenomics. Detecting CNVs is also a critical phase in the process of CYP2D6 genotyping.