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Response to clozapine in a clinically identifiable subtype of schizophrenia.

ABSTRACT: Genetic testing in psychiatry promises to improve patient care through advances in personalised medicine. However, there are few clinically relevant examples.To determine whether patients with a well-established genetic subtype of schizophrenia show a different response profile to the antipsychotic clozapine than those with idiopathic schizophrenia.We retrospectively studied the long-term safety and efficacy of clozapine in 40 adults with schizophrenia, half with a 22q11.2 deletion (22q11.2DS group) and half matched for age and clinical severity but molecularly confirmed to have no pathogenic copy number variant (idiopathic group).Both groups showed similar clinical improvement and significant reductions in hospitalisations, achieved at a lower median dose for those in the 22q11.2DS group. Most common side-effects were similarly prevalent between the two groups, however, half of the 22q11.2DS group experienced at least one rare serious adverse event compared with none of the idiopathic group. Many were successfully retried on clozapine.Individuals with 22q11.2DS-schizophrenia respond as well to clozapine treatment as those with other forms of schizophrenia, but may represent a disproportionate number of those with serious adverse events, primarily seizures. Lower doses and prophylactic (for example anticonvulsant) management strategies can help ameliorate side-effect risks. This first systematic evaluation of antipsychotic response in a genetic subtype of schizophrenia provides a proof-of-principle for personalised medicine and supports the utility of clinical genetic testing in schizophrenia.

SUBMITTER: Butcher NJ

PROVIDER: S-EPMC4459828 | biostudies-literature | 2015 Jun

REPOSITORIES: biostudies-literature

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Response to clozapine in a clinically identifiable subtype of schizophrenia.

Butcher Nancy J NJ Fung Wai Lun Alan WL Fitzpatrick Laura L Guna Alina A Andrade Danielle M DM Lang Anthony E AE Chow Eva W C EW Bassett Anne S AS

The British journal of psychiatry : the journal of mental science 20150305 6

<h4>Background</h4>Genetic testing in psychiatry promises to improve patient care through advances in personalised medicine. However, there are few clinically relevant examples.<h4>Aims</h4>To determine whether patients with a well-established genetic subtype of schizophrenia show a different response profile to the antipsychotic clozapine than those with idiopathic schizophrenia.<h4>Method</h4>We retrospectively studied the long-term safety and efficacy of clozapine in 40 adults with schizophre ...[more]

PMID: 25745132

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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.

Project description:Clozapine is the most effective antipsychotic for treatment refractory people with schizophrenia, yet many patients only partially respond. Accumulating preclinical and clinical data suggest benefits with minocycline. We tested adjunct minocycline to clozapine in a 10-week, double-blind, placebo-controlled trial. Primary outcomes tested were positive, and cognitive symptoms, while avolition, anxiety/depression, and negative symptoms were secondary outcomes.Schizophrenia and schizoaffective participants (n = 52) with persistent positive symptoms were randomized to receive adjunct minocycline (100 mg oral capsule twice daily; n = 29) or placebo (n = 23).Brief Psychiatric Rating Scale (BPRS) psychosis factor (P = 0.098; effect size [ES], 0.39) and BPRS total score (P = 0.075; ES, 0.55) were not significant. A change in total BPRS symptoms of more than or equal to 30% was observed in 7 (25%) of 28 among minocycline and 1 (4%) of 23 among placebo participants, respectively (P = 0.044). Global cognitive function (MATRICS Consensus Cognitive Battery) did not differ, although there was a significant variation in size of treatment effects among cognitive domains (P = 0.03), with significant improvement in working memory favoring minocycline (P = 0.023; ES, 0.41). The Scale for the Assessment of Negative Symptoms total score did not differ, but significant improvement in avolition with minocycline was noted (P = 0.012; ES, 0.34). Significant improvement in the BPRS anxiety/depression factor was observed with minocycline (P = 0.028; ES, 0.49). Minocycline was well tolerated with significantly fewer headaches and constipation compared with placebo.Minocycline's effect on the MATRICS Consensus Cognitive Battery composite score and positive symptoms were not statistically significant. Significant improvements with minocycline were seen in working memory, avolition, and anxiety/depressive symptoms in a chronic population with persistent symptoms. Larger studies are needed to validate these findings.

Project description:Clozapine is the most effective antipsychotic drug for schizophrenia, yet it can cause life-threatening adverse drug reactions, including myocarditis. The aim of this study was to determine whether schizophrenia patients with clozapine-induced myocarditis have a genetic predisposition compared with clozapine-tolerant controls. We measured different types of genetic variation, including genome-wide single-nucleotide polymorphisms (SNPs), coding variants that alter protein expression, and variable forms of human leucocyte antigen (HLA) genes, alongside traditional clinical risk factors in 42 cases and 67 controls. We calculated a polygenic risk score (PRS) based on variation at 96 different genetic sites, to estimate the genetic liability to clozapine-induced myocarditis. Our genome-wide association analysis identified four SNPs suggestive of increased myocarditis risk (P < 1 × 10-6), with odds ratios ranging 5.5-13.7. The SNP with the lowest P value was rs74675399 (chr19p13.3, P = 1.21 × 10-7; OR = 6.36), located in the GNA15 gene, previously associated with heart failure. The HLA-C*07:01 allele was identified as potentially predisposing to clozapine-induced myocarditis (OR = 2.89, 95% CI: 1.11-7.53), consistent with a previous report of association of the same allele with clozapine-induced agranulocytosis. Another seven HLA alleles, including HLA-B*07:02 (OR = 0.25, 95% CI: 0.05-1.2) were found to be putatively protective. Long-read DNA sequencing provided increased resolution of HLA typing and validated the HLA associations. The PRS explained 66% of liability (P value = 9.7 × 10-5). Combining clinical and genetic factors together increased the proportion of variability accounted for (r2 0.73, P = 9.8 × 10-9). However, due to the limited sample size, individual genetic associations were not statistically significant after correction for multiple testing. We report novel candidate genetic associations with clozapine-induced myocarditis, which may have potential clinical utility, but larger cohorts are required for replication.

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Response to clozapine in a clinically identifiable subtype of schizophrenia.

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Response to clozapine in a clinically identifiable subtype of schizophrenia.

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