Dataset Information

Genetic risk of clozapine-induced leukopenia and neutropenia: a genome-wide association study.

ABSTRACT:

Background

Clozapine is considered to be the most effective antipsychotic medication for schizophrenia. However, it is associated with several adverse effects such as leukopenia, and the underlying mechanism has not yet been fully elucidated. The authors performed a genome-wide association study (GWAS) in a Chinese population to identify genetic markers for clozapine-induced leukopenia (CIL) and clozapine-induced neutropenia (CIN).

Methods

A total of 1879 patients (225 CIL cases, including 43 CIN cases, and 1,654 controls) of Chinese descent were included. Data from common and rare single nucleotide polymorphisms (SNPs) were tested for association. The authors also performed a trans-ancestry meta-analysis with GWAS results of European individuals from the Clozapine-Induced Agranulocytosis Consortium (CIAC).

Results

The authors identified several novel loci reaching the threshold of genome-wide significance level (P < 5 × 10^-8). Three novel loci were associated with CIL while six were associated with CIN, and two T cell related genes (TRAC and TRAT1) were implicated. The authors also observed that one locus with evidence close to genome-wide significance (P = 5.08 × 10^-8) was near the HLA-B gene in the major histocompatibility complex region in the trans-ancestry meta-analysis.

Conclusions

The associations provide novel and valuable understanding of the genetic and immune causes of CIL and CIN, which is useful for improving clinical management of clozapine related treatment for schizophrenia. Causal variants and related underlying molecular mechanisms need to be understood in future developments.

SUBMITTER: Chen J

PROVIDER: S-EPMC8175348 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Abstract Background: Schizophrenia is a lifelong debilitating mental illness often characterized by hallucinations, delusions, and disorganized thought and behavior. Currently, antipsychotic medications serve as the best treatment option for schizophrenia, but clinical responses to antipsychotic medications are highly variable. Therefore, the demand for reliable biological predictors is high. A glutamate and N-methyl-d-asparate (NMDA) receptor hypofunction model based on pharmacologic and genetic studies have been suggested as an approach to study the pharmacogenetics of antipsychotic medications. Previous studies have shown clozapine (CLZ) displaces NMDAR antagonists and enhances NMDAR mediated neurotransmission. Previously, our group (Taylor et al, 2016) investigated 8 SNPs in the NMDAR subunit gene GRIN2B with response to CLZ and one marker (rs1072388) was nominally significant. Taylor et al (in press) more recently found the glycine transporter 1 gene (SLC6A9, rs16831558) exhibited an allele dose-dependent improvement in the positive symptoms of CC-homozygotes compared to T-allele carriers (Puncorrected = .008, Pcorrected = .08). In our current study, we examined the GRIN2A receptor gene that was genome-wide significant in the GWAS of schizophrenia by Ripke et al (2014). A SNP marker from GRIN2A (rs992266789) and one from the glutamate receptor ionotropic delta 2 (GRID2, rs1875705) were selected for our association study of CLZ treatment response. Methods: We investigated rs9922678 and rs1875705 in relation to CLZ treatment response in a prospective study consisting of 170 Caucasian patients treated with CLZ for 6 months. Treatment response was evaluated using the 18-item Brief Psychiatric Rating Scale (BPRS), using either responder vs nonresponder status or continuous change scores. Baseline score was included as a covariate. All statistical analyses were performed using IBM SPSS. Results: No significant association was observed for rs9922678 and rs1875705 with BPRS total score and responder vs nonresponder status under genotypic, allelic, and additive models. Conclusion: Although no significant results were obtained from our current study, there is still strong neurobiological evidence suggesting involvement of the glutamate system in CLZ action. Additional glutamate system genes and multiple markers should be investigated. Further studies with greater sample size are required before firm conclusions can be drawn. In addition, it would be helpful to investigate other phenotypes such as cognition and tardive dyskinesia because glutamate neurotransmission also plays a role in these areas.