Machine learning algorithm-based estimation model for the severity of depression assessed using Montgomery-Asberg depression rating scale

AIM

Depressive disorder is often evaluated using established rating scales. However, consistent data collection with these scales requires trained professionals. In the present study, the "rater & estimation-system" reliability was assessed between consensus evaluation by trained psychiatrists and the estimation by 2 models of the AI-MADRS (Montgomery-Asberg Depression Rating Scale) estimation system, a machine learning algorithm-based model developed to assess the severity of depression.

METHODS

During interviews with trained psychiatrists and the AI-MADRS estimation system, patients responded orally to machine-generated voice prompts from the AI-MADRS structured interview questions. The severity scores estimated from two models of the AI-MADRS estimation system, the max estimation model and the average estimation model, were compared with those by trained psychiatrists.

RESULTS

A total of 51 evaluation interviews conducted on 30 patients were analyzed. Pearson's correlation coefficient with the scores evaluated by trained psychiatrists was 0.76 (95% confidence interval 0.62-0.86) for the max estimation model, and 0.86 (0.76-0.92) for the average estimation model. The ANOVA ICC rater & estimation-system reliability with the evaluation scores by trained psychiatrists was 0.51 (-0.09 to 0.79) for the max estimation model, and 0.75 (0.55-0.86) for the average estimation model.

CONCLUSION

The average estimation model of AI-MADRS demonstrated substantially acceptable rater & estimation-system reliability with trained psychiatrists. Accumulating a broader training dataset and the refinement of AI-MADRS interviews are expected to improve the performance of AI-MADRS. Our findings suggest that AI technologies can significantly modernize and potentially revolutionize the realm of depression assessments.

Association between copy number variations in parkin (PRKN) and schizophrenia and autism spectrum disorder: A case-control study

AIM

The present study aimed to examine the association between copy number variations (CNVs) in parkin (PRKN) and schizophrenia (SCZ) and autism spectrum disorder (ASD) in a large case-control sample.

METHOD

Array comparative genomic hybridization was performed on 3111 cases with SCZ, 1236 cases with ASD, and 2713 controls. We systematically prioritized likely pathogenic CNVs (LP-CNVs) in PRKN and examined their association with SCZ and ASD.

RESULTS

In total, 3014 SCZ cases (96.9%), 1205 ASD cases (97.5%), and 2671 controls (98.5%) passed quality control. We found that monoallelic carriers of LP-CNVs in PRKN were common (70/6890, 1.02%) and were not at higher risk of SCZ (p = 0.29) or ASD (p = 0.72). We observed that the distribution pattern of LP-CNVs in the Japanese population was consistent with those in other populations. We also identified a patient diagnosed with SCZ and early-onset Parkinson's disease carrying biallelic pathogenic CNVs in PRKN. The absence of Parkinson's symptoms in 10 other monoallelic carriers of the same pathogenic CNV further reflects the lack of effect of monoallelic pathogenic variants in PRKN in the absence of a second hit.

CONCLUSION

The present findings suggest that monoallelic CNVs in PRKN do not confer a significant risk for SCZ or ASD. However, further studies to investigate the association between biallelic CNVs in PRKN and SCZ and ASD are warranted.

Fine-mapping genomic loci refines bipolar disorder risk genes

Bipolar disorder (BD) is a heritable mental illness with complex etiology. While the largest published genome-wide association study identified 64 BD risk loci, the causal SNPs and genes within these loci remain unknown. We applied a suite of statistical and functional fine-mapping methods to these loci, and prioritized 22 likely causal SNPs for BD. We mapped these SNPs to genes, and investigated their likely functional consequences by integrating variant annotations, brain cell-type epigenomic annotations, brain quantitative trait loci, and results from rare variant exome sequencing in BD. Convergent lines of evidence supported the roles of SCN2A, TRANK1, DCLK3, INSYN2B, SYNE1, THSD7A, CACNA1B, TUBBP5, PLCB3, PRDX5, KCNK4, AP001453.3, TRPT1, FKBP2, DNAJC4, RASGRP1, FURIN, FES, YWHAE, DPH1, GSDMB, MED24, THRA, EEF1A2, and KCNQ2 in BD. These represent promising candidates for functional experiments to understand biological mechanisms and therapeutic potential. Additionally, we demonstrated that fine-mapping effect sizes can improve performance and transferability of BD polygenic risk scores across ancestrally diverse populations, and present a high-throughput fine-mapping pipeline (https://github.com/mkoromina/SAFFARI).

Effect of single-administration of D-sorbitol pretreatment on the bitterness and continued willingness to take asenapine: a randomized, single-blind, placebo-controlled, crossover trial

BACKGROUND

Asenapine has unique orally-related side effects, such as a bitter taste induced by sublingual administration, which often results in discontinuation of the medication. While the FDA has approved black-cherry-flavored asenapine, several countries have prescribed only unflavored versions. Specifically, Asians commonly report experiencing the bitterness of asenapine because they are more sensitive to bitter tastes than other ethnic groups. In this study, with the aim of improving adherence by reducing the bitterness of asenapine, we investigated the effects of D-sorbitol, which reduced the bitterness parameters of taste sensors in our previous basic study on the bitterness and continuity of asenapine among patients with schizophrenia.

METHODS

Twenty adult patients with schizophrenia were included in this single-blind, placebo-controlled, crossover trial. Participants rinsed their mouths with single-administration of D-sorbitol or a placebo prior to each administration of asenapine. We then conducted the questionnaires and assessed changes in the bitterness of asenapine (primary end point) and willingness to continue its use (secondary end point).

RESULTS

D-sorbitol significantly improved the bitterness of asenapine (p = 0.038). Although it did not significantly increase the willingness to continue asenapine (p = 0.180), it did show improvement over the placebo in enhancing willingness to continue, especially in patients who were not accustomed to its taste.

CONCLUSION

Our findings indicate that single-administration of D-sorbitol significantly reduces the bitterness of asenapine. In countries where flavored asenapine is not available, this finding could benefit patients who were not accustomed to its bitter taste.

TRIAL REGISTRATION

This study was registered in the Japan Registry of Clinical Trials (jRCTs041210019) on May 14, 2021.

Neuropathological substrate of incident dementia in older patients with schizophrenia: A clinicopathological study

AIM

Clinical studies reported that patients with schizophrenia are at a higher risk of developing dementia than people without schizophrenia. However, early neuropathological studies have shown that the incidence of Alzheimer's disease (AD) in schizophrenia patients does not differ from that in controls. These inconsistent results may be attributable to the inclusion of non-AD dementia, but there have been few clinicopathological studies in older patients with schizophrenia based on the current neuropathological classification. This study aimed to investigate the neuropathological basis of incident dementia in older patients with schizophrenia.

METHODS

We systematically examined 32 brains of old patients with schizophrenia using standardized pathological methods. The severity of dementia-related neuropathologies was analyzed using standardized semiquantitative assessments. After excluding patients who fulfilled the neuropathological criteria, clinicopathological variables were compared between patients with and without incident dementia to identify potential differences.

RESULTS

Seven patients fulfilled the pathological criteria for AD (n = 3), argyrophilic grain disease (AGD) (n = 2), dementia with Lewy bodies (n = 1), and AGD/progressive supranuclear palsy (n = 1). Among 25 patients for whom a neuropathological diagnosis was not obtained, 10 had dementia, but the clinicopathological findings did not differ from the remaining 15 patients without dementia.

CONCLUSION

Two types of older schizophrenia patient present dementia: patients with co-existing neurodegenerative disease and patients who do not meet pathological criteria based on the current classification. To understand the neurobiological aspects of incident dementia in older patients with schizophrenia, further clinicopathological studies are needed that do not simply analyze incident dementia as a comorbidity of conventional dementia-related neuropathologies.

The Effect of a Deproteinizing Pretreatment on the Bonding Performance and Acid Resistance of a Two-step Self-etch Adhesive on Eroded Dentin

OBJECTIVES

This study evaluated how deproteinization using sodium hypochlorite (6% NaOCl) or hypochlorous acid (50 ppm HOCl) with or without the subsequent use of an arylsulfinate salt-containing agent (Clearfil DC Activator; DCA; Kuraray Noritake Dental) affects the micro-tensile bond strength (μTBS) and formation of an acid-base resistant zone (ABRZ) of a two-step self-etch adhesive on eroded dentin.

METHODS

Coronal dentin surfaces of sound human molars were exposed to 48 cycles of demineralization (1% citric acid; 5 minutes) and remineralization (buffer solution with pH=6.4; 3.5 hours). They were then assigned to experimental groups according to the pretreatment used: none (negative control), NaOCl, NaOCl+DCA, HOCl, and HOCl+DCA. Sound dentin surfaces with no pretreatment were used as a positive control. The dentin surfaces were bonded with Clearfil SE Bond 2 (Kuraray Noritake Dental), and μTBS was measured either after 24 hours or 20,000 thermal cycles (TC). The μTBS data were statistically analyzed using a mixed-model analysis of variance (ANOVA) and t-tests with Bonferroni correction. Failure mode was determined with scanning electron microscopy (SEM), which was also used for the observation of ABRZ.

RESULTS

Among experimental groups, there was no significant difference between the negative control, HOCl, and HOCl+DCA after 24 hours, but the HOCl-pretreated groups exhibited significantly higher μTBS than the negative control after TC (p<0.01). Pretreatment with NaOCl and NaOCl+DCA resulted in significantly higher μTBS (p<0.001), but the highest μTBS was measured on sound dentin (p<0.001). TC decreased μTBS significantly in all groups (p<0.001) except for sound dentin and NaOCl+DCA (p>0.05). Adhesive failures prevailed in eroded groups, whereas cohesive failures were predominant on sound dentin. ABRZ was recognized in all groups but marked morphological differences were observed.

CONCLUSIONS

The combined use of 6% NaOCl and the arylsulfinate salt-containing agent partially reversed the compromised bonding performance on eroded dentin, while the effect of 50 ppm HOCl was negligible.

Comparison of Polysomnography, Single-Channel Electroencephalogram, Fitbit, and Sleep Logs in Patients With Psychiatric Disorders: Cross-Sectional Study

BACKGROUND

Sleep disturbances are core symptoms of psychiatric disorders. Although various sleep measures have been developed to assess sleep patterns and quality of sleep, the concordance of these measures in patients with psychiatric disorders remains relatively elusive.

OBJECTIVE

This study aims to examine the degree of agreement among 3 sleep recording methods and the consistency between subjective and objective sleep measures, with a specific focus on recently developed devices in a population of individuals with psychiatric disorders.

METHODS

We analyzed 62 participants for this cross-sectional study, all having data for polysomnography (PSG), Zmachine, Fitbit, and sleep logs. Participants completed questionnaires on their symptoms and estimated sleep duration the morning after the overnight sleep assessment. The interclass correlation coefficients (ICCs) were calculated to evaluate the consistency between sleep parameters obtained from each instrument. Additionally, Bland-Altman plots were used to visually show differences and limits of agreement for sleep parameters measured by PSG, Zmachine, Fitbit, and sleep logs.

RESULTS

The findings indicated a moderate agreement between PSG and Zmachine data for total sleep time (ICC=0.46; P<.001), wake after sleep onset (ICC=0.39; P=.002), and sleep efficiency (ICC=0.40; P=.006). In contrast, Fitbit demonstrated notable disagreement with PSG (total sleep time: ICC=0.08; wake after sleep onset: ICC=0.18; sleep efficiency: ICC=0.10) and exhibited particularly large discrepancies from the sleep logs (total sleep time: ICC=-0.01; wake after sleep onset: ICC=0.05; sleep efficiency: ICC=-0.02). Furthermore, subjective and objective concordance among PSG, Zmachine, and sleep logs appeared to be influenced by the severity of the depressive symptoms and obstructive sleep apnea, while these associations were not observed between the Fitbit and other sleep instruments.

CONCLUSIONS

Our study results suggest that Fitbit accuracy is reduced in the presence of comorbid clinical symptoms. Although user-friendly, Fitbit has limitations that should be considered when assessing sleep in patients with psychiatric disorders.

Feasibility of transanal minimally invasive surgery for total pelvic exenteration for advanced primary and recurrent pelvic malignancies

BACKGROUND

The purpose of this study was to clarify the efficacy and safety of transanal minimally invasive surgery (TAMIS) for total pelvic exenteration (TPE) in advanced primary and recurrent pelvic malignancies.

METHODS

Using a prospectively collected database, we retrospectively analyzed the clinical, surgical, and pathological outcomes of TAMIS for TPE. Surgery was performed between September 2019 and April 2023. The median follow-up period was 22 months (2-45 months).

RESULTS

Fifteen consecutive patients were included in this analysis M:F = 14:1 and median (range) age was 63 (36-74). Their diagnoses were as follows: primary rectal cancer (n = 5; 33%), recurrent rectal cancer (n = 4; 27%), primary anorectal cancer (n = 5; 33%), and gastrointestinal stromal tumor (n = 1; 7%). Bladder-sparing TPE was selected for two patients (13%). In nine of 15 patients (60%) the anal sphincter could be successfully preserved, five patients (33%) required combined resection of the internal iliac vessels, and two (13%) required rectus muscle flap reconstruction. The median operative time was 723 min (561-1082), and the median intraoperative blood loss was 195 ml (30-1520). The Clavien-Dindo classifications of the postoperative complications were as follows: grade 0-2 (n = 11; 73%); 3a (n = 3; 20%); 3b (n = 1; 7%); and ≥ 4 (n = 0; 0%). No cases of conversion to laparotomy or mortality were observed. The pathological results demonstrated that R0 was achieved in 14 patients (93%).

CONCLUSIONS

The short-term outcomes of this initial experience proved that this novel approach is feasible for TPE, with low blood loss, acceptable postoperative complications, and a satisfactory R0 resection rate.

Erratum: Search for Cosmic-Ray Boosted Sub-GeV Dark Matter Using Recoil Protons at Super-Kamiokande [Phys. Rev. Lett. 130, 031802 (2023)]

This corrects the article DOI: 10.1103/PhysRevLett.130.031802.

Measurements of neutrino oscillation parameters from the T2K experiment using 3.6×1021 protons on target

The T2K experiment presents new measurements of neutrino oscillation parameters using 19.7 ( 16.3 ) × 10 20 protons on target (POT) in (anti-)neutrino mode at the far detector (FD). Compared to the previous analysis, an additional 4.7 × 10 20 POT neutrino data was collected at the FD. Significant improvements were made to the analysis methodology, with the near-detector analysis introducing new selections and using more than double the data. Additionally, this is the first T2K oscillation analysis to use NA61/SHINE data on a replica of the T2K target to tune the neutrino flux model, and the neutrino interaction model was improved to include new nuclear effects and calculations. Frequentist and Bayesian analyses are presented, including results on sin 2 θ 13 and the impact of priors on the δ CP measurement. Both analyses prefer the normal mass ordering and upper octant of sin 2 θ 23 with a nearly maximally CP-violating phase. Assuming the normal ordering and using the constraint on sin 2 θ 13 from reactors, sin 2 θ 23 = 0 . 561 - 0.032 + 0.021 using Feldman-Cousins corrected intervals, and Δ m 32 2 = 2 . 494 - 0.058 + 0.041 × 10 - 3 eV 2 using constant Δ χ 2 intervals. The CP-violating phase is constrained to δ CP = - 1 . 97 - 0.70 + 0.97 using Feldman-Cousins corrected intervals, and δ CP = 0 , π is excluded at more than 90% confidence level. A Jarlskog invariant of zero is excluded at more than 2 σ credible level using a flat prior in δ CP , and just below 2 σ using a flat prior in sin δ CP . When the external constraint on sin 2 θ 13 is removed, sin 2 θ 13 = 28 . 0 - 6.5 + 2.8 × 10 - 3 , in agreement with measurements from reactor experiments. These results are consistent with previous T2K analyses.

Low-dose sevoflurane co-administered with propofol-based general anaesthesia obliterates intra-operative neurophysiological monitoring in an infant

The influence of general anaesthetic agents on intra-operative neurophysiological monitoring in neonates and infants has rarely been reported. Propofol-based anaesthesia is recommended to avoid suppression of neurophysiological monitoring. However, the administration of propofol in children undergoing prolonged procedures, especially those younger than six months, should be carefully controlled due to the potential risk of propofol infusion syndrome. Adding a small dose of inhalational anaesthetic can be an option to reduce propofol requirements. Recent guidelines in Japan suggest limiting inhalational anaesthetics to less than 0.5 minimum alveolar concentrations when co-administered with low-dose propofol during intra-operative neuromonitoring. However, there is still insufficient evidence regarding the impact of sevoflurane on neurophysiological monitoring when co-administered with propofol in infants. This report describes a case of a three-month-old infant undergoing spinal lipoma resection in which there was a dramatic suppression of neurophysiological monitoring with the addition of 0.35-0.45% sevoflurane to propofol-based anaesthesia.

GWAS-identified bipolar disorder risk allele in the FADS1/2 gene region links mood episodes and unsaturated fatty acid metabolism in mutant mice

Large-scale genome-wide association studies (GWASs) on bipolar disorder (BD) have implicated the involvement of the fatty acid desaturase (FADS) locus. These enzymes (FADS1 and FADS2) are involved in the metabolism of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are thought to potentially benefit patients with mood disorders. To model reductions in the activity of FADS1/2 affected by the susceptibility alleles, we generated mutant mice heterozygously lacking both Fads1/2 genes. We measured wheel-running activity over six months and observed bipolar swings in activity, including hyperactivity and hypoactivity. The hyperactivity episodes, in which activity was far above the norm, usually lasted half a day; mice manifested significantly shorter immobility times on the behavioral despair test performed during these episodes. The hypoactivity episodes, which lasted for several weeks, were accompanied by abnormal circadian rhythms and a marked decrease in wheel running, a spontaneous behavior associated with motivation and reward systems. We comprehensively examined lipid composition in the brain and found that levels of certain lipids were significantly altered between wild-type and the heterozygous mutant mice, but no changes were consistent with both sexes and either DHA or EPA was not altered. However, supplementation with DHA or a mixture of DHA and EPA prevented these episodic behavioral changes. Here we propose that heterozygous Fads1/2 knockout mice are a model of BD with robust constitutive, face, and predictive validity, as administration of the mood stabilizer lithium was also effective. This GWAS-based model helps to clarify how lipids and their metabolisms are involved in the pathogenesis and treatment of BD.

Acute effect of short-term immobilization on lower leg muscle tissue hardness in healthy adults

BACKGROUND

Previous studies have reported altered neural activity in the motor cortex after short-term cast immobilization, even in healthy participants. However, the effects of short-term movement restriction on tissue structure are not well understood.

OBJECTIVE

To investigate the effects of short-term lower limb immobilization on muscle tissue hardness.

METHODS

Seventeen healthy participants were enrolled in the study. Each participant's non-dominant lower limb was fixed with a soft bandage and medical splint for 10 h. Gastrocnemius muscle tissue hardness was measured using a tissue hardness meter before cast application and immediately after cast removal. Measurements were performed five times for each lower limb, and the three values with the lowest coefficient of variance were adopted as the value of muscle tissue hardness.

RESULTS

Gastrocnemius muscle tissue hardness in the immobilized limb was lower after cast removal than that before cast application (from 53.6 to 51.8; p< 0.01), whereas the non-fixed limb showed an increase in muscle tissue hardness at the end of the experiment (from 52.9 to 54.3; p= 0.03).

CONCLUSION

The findings indicate that 10 h movement restriction induced a reduction in muscle tissue hardness, suggesting acute adverse effects of cast immobilization for orthopedic treatment.

Estimation of brain natriuretic peptide values from N-terminal pro brain natriuretic peptide levels and other factors

Funding Acknowledgements

Type of funding sources: None.

Backgrounds

Both brain natriuretic peptide (BNP) and N-terminal proBNP (NT-pro BNP) are established biomarkers that are necessary in the diagnosis and management of heart failure (HF). Recently with the introduction of angiotensin receptor-neprilysin inhibitor in the treatment of HF, the course of HF is now assessed using NT-ProBNP levels1). However, it is difficult to infer BNP concentration from NT-proBNP levels for a physician who is familiar with BNP. Generally, simultaneous measurement of BNP and NT-proBNP is not permitted in medical insurance.

Purpose

To estimate BNP concentration from NT-proBNP levels and other factors as an equivalent prognostic strength compared to the actual BNP concentration.

Methods

From August 2021 to October 2021, we measured BNP and NT-proBNP levels of patients who were known or suspected to have HF (n=200). We created a formula for estimating BNP concentration from the data of NT-proBNP, age, body mass index (BMI), white cell counts, hemoglobin (Hb), estimated glemerular filtration rate) (eGFR) and C-reactive protein (CRP) using multivariate analysis.

Results

Patients’ background were as follows: age 66.4±23.6 years, male /female : 112/88 , BMI: 23.1±5.2 kg/m2, Hb level: 12.3±2.2 g/dL, albmine level: 3.7±0.7 g/dL, eGFR level: 63.3±27.0 mL/min/1.73m², CRP level; 1.80±4.67 mg/dL, BNP level: 103.3±207.9 pg/mL, NT-proBNP level: 1,505.1±3,479.6 pg/mL (mean ± SD). There was a strong correlation between BNP concentration and NT-proBNP level when using actual measured values (r= 0.84) and when using log-transformed values (r=0.92) in these patients.Using multiple regression analysis, we created an equation that estimated

LogBNP=-0.864+0.734×LogNT-proBNP+0.005×age-0.003×eGFR-0.009×BMI+0.016×CRP (R²=0.89).

Conclusion

This equation will be useful, especially for a physician who is not familiar with NT-proBNP. Testing BNP concentrations were reliably estimated from an equation featuring NT-proBNP, eGFR, age, BMI and CRP2),3),4).

Search for Cosmic-Ray Boosted Sub-GeV Dark Matter Using Recoil Protons at Super-Kamiokande

We report a search for cosmic-ray boosted dark matter with protons using the 0.37  megaton×years data collected at Super-Kamiokande experiment during the 1996-2018 period (SKI-IV phase). We searched for an excess of proton recoils above the atmospheric neutrino background from the vicinity of the Galactic Center. No such excess is observed, and limits are calculated for two reference models of dark matter with either a constant interaction cross section or through a scalar mediator. This is the first experimental search for boosted dark matter with hadrons using directional information. The results present the most stringent limits on cosmic-ray boosted dark matter and exclude the dark matter-nucleon elastic scattering cross section between 10^{-33}cm^{2} and 10^{-27}cm^{2} for dark matter mass from 1  MeV/c^{2} to 300  MeV/c^{2}.

X chromosome aneuploidies and schizophrenia: association analysis and phenotypic characterization

AIM

The aims of the present study were: (i) to examine the association between schizophrenia (SCZ) and 47, XXY or 47, XXX in a large case-control sample; and (ii) to characterize the clinical features of patients with SCZ with these X chromosome aneuploidies.

METHODS

To identify 47, XXY and 47, XXX, array comparative genomic hybridization (aCGH) was performed in 3188 patients with SCZ and 3586 controls. We examined the association between 47, XXY and 47, XXX and SCZ in males and females separately using exact conditional tests to control for platform effects. Clinical data were retrospectively examined for patients with SCZ with X chromosome aneuploidies.

RESULTS

Of the analyzed samples, 3117 patients (97.8%) and 3519 controls (98.1%) passed our quality control. X chromosome aneuploidies were exclusively identified in patients: 47, XXY in seven patients (0.56%), 47, XXX in six patients (0.42%). Statistical analysis revealed a significant association between SCZ and 47, XXY (P = 0.028) and 47, XXX (P = 0.011). Phenotypic data were available from 12 patients. Treatment-resistance to antipsychotics and manic symptoms were observed in six patients each (four with 47, XXY and two with 47, XXX for both), respectively. Statistical analysis revealed that treatment-resistance to antipsychotics, mood stabilizer use, and manic symptoms were significantly more common in patients with 47, XXY than in male patients without pathogenic copy number variations.

CONCLUSION

These findings indicate that both 47, XXY and 47, XXX are significantly associated with risk for SCZ. Patients with SCZ with 47, XXY may be characterized by treatment-resistance and manic symptoms.

Pharmacogenomic-guided clozapine administration based on HLA-DQB1, HLA-B and SLCO1B3-SLCO1B7 variants: an effectiveness and cost-effectiveness analysis

The identification of pharmacogenetic factors that increase the susceptibility to clozapine-induced agranulocytosis or granulocytopenia (CIAG) has received increasing interest. The SLCO1B3-SCLO1B7 variant (rs149104283) and single amino acid changes in human leukocyte antigen (HLA) HLA-DQB1 (126Q) and HLA-B (158T) were associated with an increased risk of CIAG. In this study, we evaluated the effectiveness and cost-effectiveness of adding the SLCO1B3-SCLO1B7 to HLA variants as a new pharmacogenomic (PGx) approach and explored the evolution of a cohort of schizophrenic patients taking long-term clozapine as a third-line antipsychotic medication. The decision model included probabilistic and deterministic sensitivity analyses to assess the expected costs and quality-adjusted life-years (QALYs). The current monitoring scheme was compared with the PGx-guided strategy, where all patients underwent pre-emptively a genetic test before taking clozapine, over 10 years. By adding the SLCO1B3-SCLO1B7 variant into HLA variants, CIAG sensitivity increased from 36.0% to 43.0%, the specificity decreased from 89.0% to 86.9%, and the probability of cost-effectiveness improved from 74.1% to 87.8%. The incremental cost-effectiveness ratio was £16,215 per QALY and remained below the conventional decision threshold (£30,000 or US$50,000 per QALY). Therefore, the SLCO1B3-SCLO1B7 variant, as an additional risk allele to HLA variants, increases preemptive test sensitivity and improves the effectiveness and cost-effectiveness of PGx-guided clozapine administration.

Cross-Disorder Analysis of Genic and Regulatory Copy Number Variations in Bipolar Disorder, Schizophrenia, and Autism Spectrum Disorder

BACKGROUND

We aimed to determine the similarities and differences in the roles of genic and regulatory copy number variations (CNVs) in bipolar disorder (BD), schizophrenia (SCZ), and autism spectrum disorder (ASD).

METHODS

Based on high-resolution CNV data from 8708 Japanese samples, we performed to our knowledge the largest cross-disorder analysis of genic and regulatory CNVs in BD, SCZ, and ASD.

RESULTS

In genic CNVs, we found an increased burden of smaller (<100 kb) exonic deletions in BD, which contrasted with the highest burden of larger (>500 kb) exonic CNVs in SCZ/ASD. Pathogenic CNVs linked to neurodevelopmental disorders were significantly associated with the risk for each disorder, but BD and SCZ/ASD differed in terms of the effect size (smaller in BD) and subtype distribution of CNVs linked to neurodevelopmental disorders. We identified 3 synaptic genes (DLG2, PCDH15, and ASTN2) as risk factors for BD. Whereas gene set analysis showed that BD-associated pathways were restricted to chromatin biology, SCZ and ASD involved more extensive and similar pathways. Nevertheless, a correlation analysis of gene set results indicated weak but significant pathway similarities between BD and SCZ or ASD (r = 0.25-0.31). In SCZ and ASD, but not BD, CNVs were significantly enriched in enhancers and promoters in brain tissue.

CONCLUSIONS

BD and SCZ/ASD differ in terms of CNV burden, characteristics of CNVs linked to neurodevelopmental disorders, and regulatory CNVs. On the other hand, they have shared molecular mechanisms, including chromatin biology. The BD risk genes identified here could provide insight into the pathogenesis of BD.

Clozapine-specific proliferative response of peripheral blood-derived mononuclear cells in Japanese patients with clozapine-induced agranulocytosis

BACKGROUND

Although clozapine-induced granulocytopenia (CIG) is less severe than clozapine-induced agranulocytosis (CIA), and some patients with CIG may not go on to develop serious complications, clozapine is discontinued in cases of both CIA and CIG. Understanding the pathogenic mechanisms of CIA/CIG could provide better management of clozapine therapy. Recently, as a mechanistic insight into adaptive immune systems, European groups reported clozapine-specific proliferative responses and clozapine-specific T cells using blood taken from patients with CIA and/or CIG.

AIMS

The aims of our study are to support this mechanistic evidence and to investigate the difference in the lymphocyte response to clozapine between patients with CIG and those with CIA.

METHODS

Lymphocyte stimulation tests (LSTs) were conducted using CD25-positive cell-depleted peripheral blood-derived mononuclear cells (PBMCs) isolated from blood of four Japanese patients with CIA, four patients with CIG, and nine clozapine-tolerant subjects.

RESULTS

Three of four patients with CIA and one of four patients with CIG showed proliferative responses to clozapine with a stimulation index of greater than 2. In contrast, none of the nine clozapine-tolerant subjects showed any response to clozapine. Olanzapine did not stimulate PBMCs of patients with CIA, patients with CIG, or clozapine-tolerant subjects.

CONCLUSIONS

Clozapine- and CIA-specific lymphocyte reactions in a Japanese population provided supportive evidence that the pathogenesis of CIA is based on adaptive immune reactions. In addition, patients with CIG who show a positive response to an LST may at the very least not be chosen for clozapine-rechallenge and further prospective studies are desirable to verify this hypothesis.

Shared genetic components between metabolic syndrome and schizophrenia: Genetic correlation using multipopulation data sets

AIM

The genetic relationship between schizophrenia (SCZ) and other nonpsychiatric disorders remains largely unknown. We examined the shared genetic components between these disorders based on multipopulation data sets.

METHODS

We used two data sets for East Asian (EAS) and European (EUR) samples. SCZ data was based on the Psychiatric Genomics Consortium Asia with our own genome-wide association study for EAS and Psychiatric Genomics Consortium for EUR. Nonpsychiatric data (20 binary traits [mainly nonpsychiatric complex disorders] and 34 quantitative traits [mainly laboratory examinations and physical characteristics]) were obtained from Biobank Japan and UK Biobank for EAS and EUR samples, respectively. To evaluate genetic correlation, linkage disequilibrium score regression analysis was utilized with further meta-analysis for each result from EAS and EUR samples to obtain robust evidence. Subsequent mendelian randomization analysis was also included to examine the causal effect.

RESULTS

A significant genetic correlation between SCZ and several metabolic syndrome (MetS) traits was detected in the combined samples (meta-analysis between EAS and EUR data) (body mass index [r_g  = -0.10, q-value = 1.0 × 10^-9 ], high-density-lipoprotein cholesterol [r_g  = 0.072, q-value = 2.9 × 10^-3 ], blood sugar [r_g  = -0.068, q-value = 1.4 × 10^-2 ], triglycerides [r_g  = -0.052, q-value = 2.4 × 10^-2 ], systolic blood pressure [r_g  = -0.054, q-value = 3.5 × 10^-2 ], and C-reactive protein [r_g  = -0.076, q-value = 7.8 × 10^-5 ]. However, no causal relationship on SCZ susceptibility was detected for these traits based on the mendelian randomization analysis.

CONCLUSION

Our results indicate shared genetic components between SCZ and MetS traits and C-reactive protein. Specifically, we found it interesting that the correlation between MetS traits and SCZ was the opposite of that expected from clinical studies: this genetic study suggests that SCZ susceptibility was associated with reduced MetS. This implied that MetS in patients with SCZ was not associated with genetic components but with environmental factors, including antipsychotics, lifestyle changes, poor diet, lack of exercise, and living conditions.

OP0008 A NOVEL SITE-SPECIFIC PEGYLATED IL-2 WITH POTENT AND TREG-SELECTIVE ACTIVITY IN VIVO

Background

Decreased regulatory T cells (Tregs) and Treg dysfunction are hallmarks of a various autoimmune and inflammatory diseases. While low-dose IL-2 therapy induces Treg expansion in vivo and has clinical benefits in some diseases (e.g., SLE and chronic graft-versus-host disease [GvHD]), there are many concerns about adverse events due to low Treg-selectivity. Furthermore, frequent dosing is needed due to the short half-life.

Objectives

We discovered a novel site-specific PEGylated IL-2 variant, KKC80, with high Treg selectivity and a long half-life in vivo, which overcomes the issues of low-dose IL-2 therapy.

Methods

Based on the co-crystal structure of wild-type IL-2 and its heterotrimeric receptor (PBD ID: 2ERJ), amino acid residues that were to be PEGylation sites were substituted with oAzZLys, an azide-containing lysine derivative. The PEG molecule was site-specifically attached to oAzZLys-incorporated IL-2 by copper-free click chemistry. The binding property to the IL-2 receptors were measured by surface plasmon resonance (SPR). In vitro, Treg selectivity was evaluated by the IL-2-dependent proliferation activity of Tregs and NK cells from human peripheral blood mononuclear cells (PBMCs). In vivo pharmacological activity after the single subcutaneous administration in cynomolgus monkeys was measured by changes in Treg count and Treg activation status in peripheral blood by flow cytometry. Pharmacokinetic parameters were calculated according to serum PEGylated IL-2 concentration. Efficacy in mouse xenogeneic GvHD model using human PBMC-transplanted NOG mice and in monkey DTH model were evaluated.

Results

A novel PEGylated IL-2, KKC80 (human IL-2 desA1/C125S /I129oAzZLys_W-shaped 80 kDa PEG) was discovered by optimizing the PEGylation site and PEG structure based on Treg selectivity and PK. SPR analysis showed that the binding affinity of KKC80 to CD25 was moderately decreased from wild-type IL-2, while binding affinity of KKC80 to IL-2Rβγ was remarkably decreased due to a significant change of the association rate constant. In vitro, wild-type IL-2 activated both Tregs and NK cells in the same concentration range, whereas KKC80 selectively activated Tregs. The Treg selectivity of KKC80 was comparable to another IL-2 mutein, Fc.IL-2 V91K. KKC80, but not Fc.IL-2 V91K, retained its biological activity, even in the presence of a large amount of recombinant soluble CD25, which mimicked the endogenous decoy receptor for IL-2. In monkeys, KKC80 selectively increased peripheral blood Tregs in a dose-dependent manner; the average maximum rate of increase of Treg count in animals treated with 0.01, 0.03, 0.1, 0.3 and 1 mg/kg was 1.5, 3.5, 28, 50 and 154-fold, respectively. In contrast to Tregs, the rates of increase of conventional CD4+ T, CD8+ T and NK cells were low. The Treg increase peaked on day 8 or 11 and lasted for over day 29. KKC80 showed a more sustained upregulation of functional Treg markers (e.g., Foxp3 and CD25) in comparison to Fc.IL-2 V91K. The half-life of KKC80 was calculated as 83.5 to 150 h. At high doses, inflammation-related adverse effects, including increased CRP (≥0.3 mg/kg) and deterioration of general conditions (1 mg/kg) were observed. In the mouse xenogenic GvHD model, KKC80 ameliorated GvHD symptoms and suppressed multiple tissue inflammation markers. Decreased soluble CD25 and IFN-γ were also confirmed, suggesting Treg-mediated anti-inflammatory effect by KKC80 administration were exerted in vivo. In the monkey DTH model, KKC80 suppressed skin inflammation and antibody production.

Conclusion

Among next-generation IL-2 variants, KKC80 showed a best-in-class biological profile for Treg activation. A drastic and sustained increase of Tregs with high Treg-selectivity and anti-inflammatory effects were observed in vivo. These data suggest that in comparison to current IL-2 therapy, KKC80 provides superior therapeutic index and efficacy in patients with autoimmune and inflammatory diseases.

Figure 1.

Disclosure of Interests

Masahiro Ikeda Employee of: Kyowa Kirin Co., Ltd., Shinpei Yamaguchi Employee of: Kyowa Kirin Co., Ltd., Masumi Murakami Employee of: Kyowa Kirin Co., Ltd., Shigeki Takaoka Employee of: Kyowa Kirin Co., Ltd., Yasuko Sakaguchi Employee of: Kyowa Kirin Co., Ltd., Shunki Yasui Employee of: Kyowa Kirin Co., Ltd., Kousuke Iijima Employee of: Kyowa Kirin Co., Ltd., Kenichiro Nanya Employee of: Kyowa Kirin Co., Ltd., Hideyuki Onodera Employee of: Kyowa Kirin Co., Ltd., Toru Amano Employee of: Kyowa Kirin Co., Ltd.

Mapping genomic loci implicates genes and synaptic biology in schizophrenia

Schizophrenia has a heritability of 60-80%1, much of which is attributable to common risk alleles. Here, in a two-stage genome-wide association study of up to 76,755 individuals with schizophrenia and 243,649 control individuals, we report common variant associations at 287 distinct genomic loci. Associations were concentrated in genes that are expressed in excitatory and inhibitory neurons of the central nervous system, but not in other tissues or cell types. Using fine-mapping and functional genomic data, we identify 120 genes (106 protein-coding) that are likely to underpin associations at some of these loci, including 16 genes with credible causal non-synonymous or untranslated region variation. We also implicate fundamental processes related to neuronal function, including synaptic organization, differentiation and transmission. Fine-mapped candidates were enriched for genes associated with rare disruptive coding variants in people with schizophrenia, including the glutamate receptor subunit GRIN2A and transcription factor SP4, and were also enriched for genes implicated by such variants in neurodevelopmental disorders. We identify biological processes relevant to schizophrenia pathophysiology; show convergence of common and rare variant associations in schizophrenia and neurodevelopmental disorders; and provide a resource of prioritized genes and variants to advance mechanistic studies.

Novel missense SETD1A variants in Japanese patients with schizophrenia: Resequencing and association analysis

SETD1A has been identified as a substantial risk gene for schizophrenia. To further investigate the role of SETD1A in the genetic etiology of schizophrenia in the Japanese population, we performed resequencing and association analyses. First, we resequenced the SETD1A coding regions of 974 patients with schizophrenia. Then, we genotyped variants, prioritized via resequencing, in 2,027 patients with schizophrenia and 2,664 controls. Next, we examined the association between SETD1A and schizophrenia in 3,001 patients with schizophrenia and 2,664 controls. Finally, we performed a retrospective chart review of patients with prioritized SETD1A variants. We identified two novel missense variants (p.Ser575Pro and p.Glu857Gln) via resequencing. We did not detect these variants in 4,691 individuals via genotyping. These variants were not significantly associated with schizophrenia in the association analysis. Additionally, we found that a schizophrenia patient with the p.Glu857Gln variant had developmental delays. In conclusion, novel SETD1A missense variants were exclusively identified in Japanese patients with schizophrenia. However, our study does not provide evidence for the contribution of these variants to the genetic etiology of schizophrenia in the Japanese population.

Precise Measurement of Differential Cross Sections of the Σ^{-}p→Λn Reaction in Momentum Range 470-650 MeV/c

The differential cross sections of the Σ^{-}p→Λn reaction were measured accurately for the Σ^{-} momentum (p_{Σ}) ranging from 470 to 650  MeV/c at the J-PARC Hadron Experimental Facility. Precise angular information about the Σ^{-}p→Λn reaction was obtained for the first time by detecting approximately 100 reaction events at each angular step of Δcosθ=0.1. The obtained differential cross sections show a slightly forward-peaking structure in the measured momentum regions. The cross sections integrated for -0.7≤cosθ≤1.0 were obtained as 22.5±0.68 [statistical error(stat.)] ±0.65 [systematic error(syst.)] mb and 15.8±0.83(stat)±0.52(syst)  mb for 470<p_{Σ}(MeV/c)<550 and 550<p_{Σ}(MeV/c)<650, respectively. These results show a drastic improvement compared with past measurements of the hyperon-proton scattering experiments. They will play essential roles in updating the theoretical models of the baryon-baryon interactions.

Increased plasma drug concentration and decreased additional insulin secretion following oral administration of glimepiride in Spontaneously Diabetic Torii rats

We aimed to evaluate the pharmacokinetics and pharmacological effects of glimepiride in the Spontaneously Diabetic Torii (SDT) rat, which is a non-obese model of type 2 diabetes. After oral administration of glimepiride (10 mg/kg), the maximum plasma concentrations and the area under the curve from 0 to 6 h of glimepiride in SDT rats were significantly higher than those in age-matched Sprague-Dawley rats. Whereas, additional insulin secretion following glimepiride treatment was markedly reduced in SDT rats. Thus, the SDT rat can be regarded as a model that reflects type 2 diabetes with reduced insulin secretory capacity. Our findings suggested that glimepiride could be ineffective in sever type 2 diabetic patients.

Varlitinib plus capecitabine in second-line advanced biliary tract cancer: a randomized, phase II study (TreeTopp)

Background

Patients with advanced biliary tract cancer who progress on first-line therapy have limited treatment options. The TreeTopp study assessed varlitinib, a reversible small molecule pan-human epidermal growth factor receptor inhibitor, plus capecitabine in previously treated advanced biliary tract cancer.

Patients and methods

This global, double-blind, randomized, placebo-controlled phase II study enrolled patients with confirmed unresectable or metastatic biliary tract cancer and disease progression after one prior line of gemcitabine-containing chemotherapy. Patients received oral varlitinib 300 mg or placebo twice daily (b.i.d.) for 21 days, plus oral capecitabine 1000 mg/m² b.i.d. on days 1-14, in 21-day treatment cycles. Co-primary endpoints were objective response rate and progression-free survival (PFS) according to RECIST v1.1 by Independent Central Review.

Results

In total, 127 patients received varlitinib plus capecitabine (n = 64) or placebo plus capecitabine (n = 63). The objective response rate was 9.4% with varlitinib plus capecitabine versus 4.8% with capecitabine alone (odds ratio 2.28; P = 0.42). Median PFS was 2.83 versus 2.79 months [hazard ratio (HR), 0.90; 95% confidence interval (CI), 0.60-1.37; P = 0.63] and overall survival was 7.8 versus 7.5 months (HR, 1.11; 95% CI, 0.69-1.79; P = 0.66), respectively. In a subgroup analysis, the addition of varlitinib appeared to provide a PFS benefit in female patients (median, 4.1 versus 2.8 months; HR, 0.59; 95% CI, 0.28-1.23) and those with gallbladder cancer (median, 2.9 versus 1.6 months; HR, 0.55; 95% CI, 0.26-1.19). Grade ≥3 treatment-emergent adverse events were reported in 65.6% of patients receiving varlitinib plus capecitabine versus 58.7% of those receiving capecitabine alone.

Conclusions

In patients with advanced biliary tract cancer, second-line treatment with varlitinib plus capecitabine was well tolerated but did not improve efficacy versus capecitabine alone. A PFS benefit was suggested in female patients and those with gallbladder cancer.

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In advanced biliary tract cancer, second-line varlitinib plus capecitabine did not improve efficacy versus capecitabine alone.

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Varlitinib was well tolerated in combination with capecitabine.

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Subgroup analyses suggested varlitinib plus capecitabine may benefit female patients and those with gallbladder cancer.

Cost effectiveness of pharmacogenetic-guided clozapine administration based on risk of HLA variants in Japan and the UK

Pharmacogenetics/pharmacogenomics have enabled the detection of risk of human leukocyte antigen (HLA) variants for clozapine-induced agranulocytosis/granulocytopenia (CIAG). To apply this evidence to the clinical setting, we compared the cost-effectiveness of the proposed "HLA-guided treatment schedule" and the "current schedule" being used in Japan and the United Kingdom (UK) (absolute neutrophil count (ANC) cutoff at 1500/mm³); in the "HLA-guided treatment schedules," we considered a situation wherein the HLA test performed before clozapine initiation could provide "a priori information" by detecting patients harboring risk of HLA variants (HLA-B*59:01 and "HLA-B 158T/HLA-DQB1 126Q" for Japanese and Caucasian populations, respectively), a part of whom can then avoid CIAG onset (assumed 30% "prevention rate"). For the primary analysis, we estimated the incremental cost-effectiveness ratio (ICER) of "HLA-guided treatment schedule" and "current schedule" used in Japan and the UK, using a Markov model to calculate the cost and quality-adjusted life years (QALYs) over a 10-year time period. Furthermore, as an explorative analysis, we simulated several situations with various ANC cutoffs (1000/mm³ and 500/mm³) and plotted the cost/QALYs for each option to identify the best, or estimate the next best candidate option applicable in actual clinical settings. The primary probabilistic analysis showed that the "HLA-guided treatment schedule" was more cost effective than the "current schedule"; the ICER was £20,995 and £21,373 for the Japanese and the UK populations, respectively. Additional simulation revealed that the treatment option of ANC cutoff at 500/mm³ without HLA screening was the most cost-effective option; however, several options may be candidates to break away from the "current schedule" of ANC cutoff at 1500/mm³. Owing to its cost-effectiveness, we propose such pharmacogenetic-guided/pharmacogenomic-guided clozapine treatment for use in the real-world setting, which provides key information for optimization of clinical guidelines for high-risk patients for gradual change of clozapine treatment schedule under the safety consideration.

Genome-wide association study of more than 40,000 bipolar disorder cases provides new insights into the underlying biology

Bipolar disorder is a heritable mental illness with complex etiology. We performed a genome-wide association study of 41,917 bipolar disorder cases and 371,549 controls of European ancestry, which identified 64 associated genomic loci. Bipolar disorder risk alleles were enriched in genes in synaptic signaling pathways and brain-expressed genes, particularly those with high specificity of expression in neurons of the prefrontal cortex and hippocampus. Significant signal enrichment was found in genes encoding targets of antipsychotics, calcium channel blockers, antiepileptics and anesthetics. Integrating expression quantitative trait locus data implicated 15 genes robustly linked to bipolar disorder via gene expression, encoding druggable targets such as HTR6, MCHR1, DCLK3 and FURIN. Analyses of bipolar disorder subtypes indicated high but imperfect genetic correlation between bipolar disorder type I and II and identified additional associated loci. Together, these results advance our understanding of the biological etiology of bipolar disorder, identify novel therapeutic leads and prioritize genes for functional follow-up studies.

Impact of the 12-gene recurrence score assay on deciding adjuvant chemotherapy for stage II and IIIA/B colon cancer: the SUNRISE-DI study

BACKGROUND

Recent advances in adjuvant chemotherapy for early colon cancer have widened physicians' recommendations on the regimen and duration (3 or 6 months) of the treatment. We conducted this prospective study to evaluate whether the 12-gene recurrence score (12-RS) assay affected physicians' recommendations on adjuvant treatment selection.

PATIENTS AND METHODS

Patients with stage IIIA/IIIB or stage II colon cancer were enrolled. After the patients discussed adjuvant treatment with their treating physicians, the physicians filled in the questionnaire before assay indicating the treatment recommendation. When the 12-RS assay results were available, the physicians again filled in the questionnaire after assay. The primary endpoint was the rate of change in treatment recommendations from before to after the assay, with a threshold rate of change being 20%. Patients with stage IIIA/B to II were enrolled in a ratio of 2 : 1.

RESULTS

Overall, the treatment recommendations changed in 40% of cases after obtaining 12-RS assay results. Recommendations were changed in 45% (80/178; 95% confidence interval, 37% to 53%; P < 0.001) and 30% (29/97; 95% confidence interval, 21% to 40%; P < 0.001) of patients with stage IIIA/B and II colon cancer, respectively. Patients with stage IIIA/B cancer had significantly more change than those with stage II cancer (P = 0.0148). From before to after the 12-RS assay, the percentage of patients whose physicians reported being confident in their treatment recommendations significantly increased from 54% to 81% in stage IIIA/B (P < 0.001) and from 65% to 83% in stage II (P < 0.001).

CONCLUSION

Our study confirmed the usefulness of the 12-RS assay in aiding the physician-patient decision-making process for tailoring adjuvant chemotherapy for stage IIIA/B colon cancer.

1q21.1 distal copy number variants are associated with cerebral and cognitive alterations in humans

Low-frequency 1q21.1 distal deletion and duplication copy number variant (CNV) carriers are predisposed to multiple neurodevelopmental disorders, including schizophrenia, autism and intellectual disability. Human carriers display a high prevalence of micro- and macrocephaly in deletion and duplication carriers, respectively. The underlying brain structural diversity remains largely unknown. We systematically called CNVs in 38 cohorts from the large-scale ENIGMA-CNV collaboration and the UK Biobank and identified 28 1q21.1 distal deletion and 22 duplication carriers and 37,088 non-carriers (48% male) derived from 15 distinct magnetic resonance imaging scanner sites. With standardized methods, we compared subcortical and cortical brain measures (all) and cognitive performance (UK Biobank only) between carrier groups also testing for mediation of brain structure on cognition. We identified positive dosage effects of copy number on intracranial volume (ICV) and total cortical surface area, with the largest effects in frontal and cingulate cortices, and negative dosage effects on caudate and hippocampal volumes. The carriers displayed distinct cognitive deficit profiles in cognitive tasks from the UK Biobank with intermediate decreases in duplication carriers and somewhat larger in deletion carriers-the latter potentially mediated by ICV or cortical surface area. These results shed light on pathobiological mechanisms of neurodevelopmental disorders, by demonstrating gene dose effect on specific brain structures and effect on cognitive function.

Functional Characterization of the Effects of N-acetyltransferase 2 Alleles on N-acetylation of Eight Drugs and Worldwide Distribution of Substrate-Specific Diversity

Variability in the enzymatic activity of N-acetyltransferase 2 (NAT2) is an important contributor to interindividual differences in drug responses. However, there is little information on functional differences in N-acetylation activities according to NAT2 phenotypes, i.e., rapid, intermediate, slow, and ultra-slow acetylators, between different substrate drugs. Here, we estimated NAT2 genotypes in 990 Japanese individuals and compared the frequencies of different genotypes with those of different populations. We then calculated in vitro kinetic parameters of four NAT2 alleles (NAT2^∗4, ^∗5, ^∗6, and ^∗7) for N-acetylation of aminoglutethimide, diaminodiphenyl sulfone, hydralazine, isoniazid, phenelzine, procaineamide, sulfamethazine (SMZ), and sulfapyrizine. NAT2^∗5, ^∗6, and ^∗7 exhibited significantly reduced N-acetylation activities with lower Vmax and CLint values of all drugs when compared with NAT2^∗4. Hierarchical clustering analysis revealed that 10 NAT2 genotypes were categorized into three or four clusters. According to the results of in vitro metabolic experiments using SMZ as a substrate, the frequencies of ultra-slow acetylators were calculated to be 29.05–54.27% in Europeans, Africans, and South East Asians, whereas Japanese and East Asian populations showed lower frequencies (4.75 and 11.11%, respectively). Our findings will be helpful for prediction of responses to drugs primarily metabolized by NAT2.

Identification and functional characterization of the extremely long allele of the serotonin transporter-linked polymorphic region

SLC6A4, which encodes the serotonin transporter, has a functional polymorphism called the serotonin transporter-linked polymorphic region (5-HTTLPR). The 5-HTTLPR consists of short (S) and long (L) alleles, each of which has 14 or 16 tandem repeats. In addition, the extralong (XL) and other rare alleles have been reported in 5-HTTLPR. Although they are more frequent in Asian and African than in other populations, the extent of variations and allele frequencies (AFs) were not addressed in a large population. Here, we report the AFs of the rare alleles in a large number of Japanese subjects (N = 2894) consisting of two cohorts. The first cohort (case-control study set, CCSS) consisted of 1366 subjects, including 485 controls and 881 patients with psychosis (bipolar disorder or schizophrenia). The second cohort (the Arao cohort study set, ACSS) consisted of 1528 elderly subjects. During genotyping, we identified 11 novel 5-HTTLPR alleles, including 3 XL alleles. One novel allele had the longest subunit ever reported, consisting of 28 tandem repeats. We named this XL_28-A. An in vitro luciferase assay revealed that XL_28-A has no transcriptional activity. XL_28-A was found in two unrelated patients with bipolar disorder in the CCSS and one healthy subject in the ACSS who did not show depressive symptoms or a decline in cognitive function. Therefore, it is unlikely that XL_28-A is associated with psychiatric disorders, despite its apparent functional deficit. Our results suggest that unraveling the complex genetic variations of 5-HTTLPR will be important for further understanding its role in psychiatric disorders.