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  1. Sinniah D, Lin HP, Kwan PW, Somasundram K
    PMID: 7344086
    A review of 20 cases of neuroblastoma at the University Hospital, Kuala Lumpur from 1967 to 1980 reveals six infants aged 2 to 13 months with stage IV·S disease, associated with an unusually good prognosis. Four of the six patients presented with hepatomegaly, one had skin nodules and another paresis of the lower limbs. The primary tumour was located infra-diaphragmatically in all cases, four had disease in the bone marrow but none had radiological evidence of bone involvement. Although not systematic, with limited treatment of low dose radiation and mild chemotherapy, four patients are alive and well, one absconded and one died of septicaemia. It is important to define this special category as an unexpectedly good survival is possible with minimal therapy. Death is more likely to result from over-zealous treatment than from the disease itself.
  2. Ng KP, Soo-Hoo TS, Koh MT, Kwan PW
    Med J Malaysia, 1994 Dec;49(4):424-6.
    PMID: 7674982
    Intensive chemotherapy has prolonged survival in cancer patients. Unfortunately it has also predisposed them to unusual infections because of their immunocompromised state. We report a case of fungal septicaemia caused by Geotrichum candidum, an imperfect yeast of low virulence in a young girl with acute lymphoblastic leukaemia. It was successfully treated with amphotericin B. The morphological characteristics of this fungus leading to its identification are described.
  3. Lim KS, Lotay N, White R, Kwan P
    Epilepsy Behav, 2016 Jul 1;61:224-230.
    PMID: 27376872 DOI: 10.1016/j.yebeh.2016.05.018
    The purpose of this study was to evaluate the efficacy and safety of adjunctive retigabine/ezogabine (RTG/EZG) therapy in Asian adults with partial-onset seizures.
  4. Kwan PW, Khoo BH, Lam KL, Puthucheary SD
    Med J Malaysia, 1979 Sep;34(1):71-5.
    PMID: 396463
  5. Haerian BS, Baum L, Tan HJ, Kwan P, Raymond AA, Saruwatari J, et al.
    Pharmacogenomics, 2012 Oct;13(13):1477-85.
    PMID: 23057548 DOI: 10.2217/pgs.12.127
    Approximately 30% of epilepsy patients do not response to antiepileptic drugs (AEDs). The functional SCN1A IVS5N+5 polymorphism may play a role in response to some AEDs. The purpose of this study was to examine this hypothesis in a cohort study of Malaysian and Hong Kong Chinese epilepsy patients on sodium valproate (VPA) monotherapy and in a meta-analysis.
  6. Paudel YN, Angelopoulou E, Jones NC, O'Brien TJ, Kwan P, Piperi C, et al.
    ACS Chem Neurosci, 2019 10 16;10(10):4199-4212.
    PMID: 31532186 DOI: 10.1021/acschemneuro.9b00460
    Emerging findings point toward an important interconnection between epilepsy and Alzheimer's disease (AD) pathogenesis. Patients with epilepsy (PWE) commonly exhibit cognitive impairment similar to AD patients, who in turn are at a higher risk of developing epilepsy compared to age-matched controls. To date, no disease-modifying treatment strategy is available for either epilepsy or AD, reflecting an immediate need for exploring common molecular targets, which can delineate a possible mechanistic link between epilepsy and AD. This review attempts to disentangle the interconnectivity between epilepsy and AD pathogenesis via the crucial contribution of Tau protein. Tau protein is a microtubule-associated protein (MAP) that has been implicated in the pathophysiology of both epilepsy and AD. Hyperphosphorylation of Tau contributes to the different forms of human epilepsy and inhibition of the same exerted seizure inhibitions and altered disease progression in a range of animal models. Moreover, Tau-protein-mediated therapy has demonstrated promising outcomes in experimental models of AD. In this review, we discuss how Tau-related mechanisms might present a link between the cause of seizures in epilepsy and cognitive disruption in AD. Untangling this interconnection might be instrumental in designing novel therapies that can minimize epileptic seizures and cognitive deficits in patients with epilepsy and AD.
  7. Haerian BS, Baum L, Kwan P, Tan HJ, Raymond AA, Mohamed Z
    Pharmacogenomics, 2013 Jul;14(10):1153-66.
    PMID: 23859570 DOI: 10.2217/pgs.13.104
    Aim: Approximately a third of newly diagnosed epilepsy patients do not respond to antiepileptic drugs (AEDs). Evidence suggests that low penetrance variants in the genes of drug targets such as voltage-gated sodium channels may be involved in drug responsiveness. To examine this hypothesis, we compared data from two epilepsy cohorts from Malaysia and Hong Kong, as well as a meta-analysis from published data.

    Materials & methods: Genotype analysis of 39 polymorphisms located in the SCN1A, SCN2A and SCN3A genes was performed on 1504 epilepsy patients from Malaysia and Hong Kong who were receiving AEDs. Meta-analysis was performed for pooled data of SCN1A rs3812718 and rs2298771, and SCN2A rs17183814 polymorphisms.

    Results: Our data from the Hong Kong and Malaysia cohorts showed no significant allele, genotype and haplotype association of polymorphisms in the SCN1A, SCN2A, and SCN3A genes with drug responsiveness in epilepsy. This finding was supported by a meta-analysis for SCN1A rs3812718 and rs2298771, and for SCN2A rs17183814 polymorphisms.

    Conclusion: Our comprehensive study suggests that common polymorphisms in SCN1A, SCN2A and SCN3A do not play major roles in influencing response to AEDs.
  8. Kwan P, Cabral-Lim L, D'Souza W, Jain S, Lee BI, Liao W, et al.
    Epilepsia, 2015 May;56(5):667-73.
    PMID: 25823580 DOI: 10.1111/epi.12957
    The Asia-Oceanian region is the most populous region in the world. Although there has been substantial economic development and improvement in health services in recent years, epilepsy remains generally an underrecognized and understudied condition. To help promote research in the region, the Commission on Asian and Oceanian Affairs (CAOA) of the International League Against Epilepsy (ILAE) appointed the Research Task Force (RTF) to facilitate the development of research priorities for the region. Research that focuses on issues that are unique or of particular importance in the Asia-Oceanian region is encouraged, and that captures the impact of the dynamic socioeconomic changes taking place in the region is emphasized. Based on these considerations, we propose research "dimensions" as priorities within the Asia-Oceanian region. These are studies (1) that would lead to fuller appreciation of the health burden of epilepsy, particularly the treatment gap; (2) that would lead to better understanding of the causes of epilepsy; (3) that would alleviate the psychosocial consequences of epilepsy; (4) that would develop better therapies and improved therapeutic outcomes; and (5) that would improve the research infrastructure.
  9. Sha'ari HM, Haerian BS, Baum L, Saruwatari J, Tan HJ, Rafia MH, et al.
    Pharmacogenomics, 2014 Mar;15(4):459-66.
    PMID: 24624913 DOI: 10.2217/pgs.13.239
    To examine the relevance of ABCC2 polymorphisms to drug responsiveness in epilepsy cohorts from the Asia Pacific region.
  10. Haerian BS, Baum L, Kwan P, Cherny SS, Shin JG, Kim SE, et al.
    Mol Neurobiol, 2016 10;53(8):5457-67.
    PMID: 26452361 DOI: 10.1007/s12035-015-9457-y
    Gamma-aminobutyric acid receptor (GABA-A) is the most common receptor of fast synaptic inhibition in the human brain. Gamma protein encoded by the GABRG2 gene is one of the subunits of the GABA-A receptor, which plays an essential role in the function of this receptor. Several studies have identified various febrile seizure (FS) and epilepsy risk variants of GABRG2 gene in different populations, but some others did not support these results. The aim of this case-control study is to investigate whether GABRG2 polymorphisms contribute to susceptibility for FS and epilepsy in pooled data of three cohorts, from Malaysia (composed of Malay, Chinese, and Indian), Hong Kong, and Korea. Furthermore, the pooled dataset of these cohorts with previous reports were meta-analyzed for determining the risk effect size of the rs211037 polymorphism on FS and symptomatic epilepsy (SE). The rs211037, rs210987, rs440218, rs2422106, rs211014, and rs401750 polymorphisms were genotyped in the 6442 subjects (1729 epilepsy and 4713 controls). Results of the case-control study showed associations between rs211037 and the risk of SE in the pooled data from all cohorts (T vs. C, p = 3 × 10(-5), and TT vs. CC, p = 2 × 10(-5)) and the risk of partial seizure in the combined data of Malaysia and Hong Kong (both T vs. C and TT vs. CC, p = 2 × 10(-6)). The rs211037-rs210987 and rs2422106-rs211014-rs401750 haplotypes were also associated with susceptibility to SE in Chinese. Meta-analysis of all Asians identified association between rs211037 and FS and SE (T vs. C, p = 4 × 10(-4), and p = 4 × 10(-3), respectively). In conclusion, rs211037 alone may be a risk factor for FS, partial seizure, and SE, and in linkage disequilibrium with rs210987 can contribute to FS and SE in Asians, particularly in Chinese.
  11. Sha'ari HM, Haerian BS, Baum L, Tan HJ, Rafia MH, Kwan P, et al.
    Mol Neurobiol, 2016 07;53(5):2869-2877.
    PMID: 25876511 DOI: 10.1007/s12035-015-9150-1
    Epilepsy is a common neurological disease characterized by recurrent unprovoked seizures. Evidence suggested that abnormal activity of brain-derived neurotrophic factor (BDNF) contributes to the pathogenesis of epilepsy. Some previous studies identified association between genetic variants of BDNF and risk of epilepsy. In this study, this association has been examined in the Hong Kong and Malaysian epilepsy cohorts. Genomic DNA of 6047 subjects (1640 patients with epilepsy and 4407 healthy individuals) was genotyped for rs6265, rs11030104, rs7103411, and rs7127507 polymorphisms by using Sequenom MassArray and Illumina HumanHap 610-Quad or 550-Duo BeadChip arrays techniques. Results showed significant association between rs6265 T, rs7103411 C, and rs7127507 T and cryptgenic epilepsy risk (p = 0.00003, p = 0.0002, and p = 0.002, respectively) or between rs6265 and rs7103411 and symptomatic epilepsy risk in Malaysian Indians (TT vs. CC, p = 0.004 and T vs. C, p = 0.0002, respectively) as well as between rs6265 T and risk of cryptogenic epilepsy in Malaysian Chinese (p = 0.005). The Trs6265-Crs7103411-Trs7127507 was significantly associated with cryptogenic epilepsy in Malaysian Indians (p = 0.00005). In conclusion, our results suggest that BDNF polymorphisms might contribute to the risk of epilepsy in Malaysian Indians and Chinese.
  12. Mullan KA, Anderson A, Shi YW, Ding JH, Ng CC, Chen Z, et al.
    Epilepsia, 2022 Feb 16.
    PMID: 35170024 DOI: 10.1111/epi.17182
    OBJECTIVE: Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are severe cutaneous adverse drug reactions. Antiseizure medications (ASMs) with aromatic ring structure, including carbamazepine, are among the most common culprits. Screening for human leukocyte antigen (HLA) allele HLA-B*15:02 is recommended prior to initiating treatment with carbamazepine in Asians, but this allele has low positive predictive value.

    METHODS: We performed whole genome sequencing and analyzed 6 199 696 common variants among 113 aromatic ASM-induced SJS/TEN cases and 84 tolerant controls of Han Chinese ethnicity.

    RESULTS: In the primary analysis, nine variants reached genome-wide significance (p p = .001; homozygotes: relative risk = .23, p p < 5e-6) identified through the primary and subanalyses (stratified by HLA-B*15:02 status and drug exposure) suggests that genetic variation within regulatory DNA may contribute to risk indirectly by disrupting the regulation of pathology-related genes. The genes implicated were specific either to the primary analysis (CD9), HLA-B*15:02 carriers (DOCK10), noncarriers (ABCA1), carbamazepine exposure (HLA-E), or phenytoin exposure (CD24).

    SIGNIFICANCE: We identified variants that could explain why some carriers of HLA-B*15:02 tolerate treatment, and why some noncarriers develop ASM-induced SJS/TEN. Additionally, this analysis suggests that the mixing of HLA-B*15:02 carrier status in previous studies might have masked variants contributing to susceptibility, and that inheritance of risk for ASM-induced SJS/TEN is complex, likely involving multiple risk variants.

  13. Hakeem H, Feng W, Chen Z, Choong J, Brodie MJ, Fong SL, et al.
    JAMA Neurol, 2022 Oct 01;79(10):986-996.
    PMID: 36036923 DOI: 10.1001/jamaneurol.2022.2514
    IMPORTANCE: Selection of antiseizure medications (ASMs) for epilepsy remains largely a trial-and-error approach. Under this approach, many patients have to endure sequential trials of ineffective treatments until the "right drugs" are prescribed.

    OBJECTIVE: To develop and validate a deep learning model using readily available clinical information to predict treatment success with the first ASM for individual patients.

    DESIGN, SETTING, AND PARTICIPANTS: This cohort study developed and validated a prognostic model. Patients were treated between 1982 and 2020. All patients were followed up for a minimum of 1 year or until failure of the first ASM. A total of 2404 adults with epilepsy newly treated at specialist clinics in Scotland, Malaysia, Australia, and China between 1982 and 2020 were considered for inclusion, of whom 606 (25.2%) were excluded from the final cohort because of missing information in 1 or more variables.

    EXPOSURES: One of 7 antiseizure medications.

    MAIN OUTCOMES AND MEASURES: With the use of the transformer model architecture on 16 clinical factors and ASM information, this cohort study first pooled all cohorts for model training and testing. The model was trained again using the largest cohort and externally validated on the other 4 cohorts. The area under the receiver operating characteristic curve (AUROC), weighted balanced accuracy, sensitivity, and specificity of the model were all assessed for predicting treatment success based on the optimal probability cutoff. Treatment success was defined as complete seizure freedom for the first year of treatment while taking the first ASM. Performance of the transformer model was compared with other machine learning models.

    RESULTS: The final pooled cohort included 1798 adults (54.5% female; median age, 34 years [IQR, 24-50 years]). The transformer model that was trained using the pooled cohort had an AUROC of 0.65 (95% CI, 0.63-0.67) and a weighted balanced accuracy of 0.62 (95% CI, 0.60-0.64) on the test set. The model that was trained using the largest cohort only had AUROCs ranging from 0.52 to 0.60 and a weighted balanced accuracy ranging from 0.51 to 0.62 in the external validation cohorts. Number of pretreatment seizures, presence of psychiatric disorders, electroencephalography, and brain imaging findings were the most important clinical variables for predicted outcomes in both models. The transformer model that was developed using the pooled cohort outperformed 2 of the 5 other models tested in terms of AUROC.

    CONCLUSIONS AND RELEVANCE: In this cohort study, a deep learning model showed the feasibility of personalized prediction of response to ASMs based on clinical information. With improvement of performance, such as by incorporating genetic and imaging data, this model may potentially assist clinicians in selecting the right drug at the first trial.

  14. Baum L, Haerian BS, Ng HK, Wong VC, Ng PW, Lui CH, et al.
    Hum Genet, 2014 May;133(5):651-9.
    PMID: 24337656 DOI: 10.1007/s00439-013-1405-1
    High-frequency action potentials are mediated by voltage-gated sodium channels, composed of one large α subunit and two small β subunits, encoded mainly by SCN1A, SCN2A, SCN3A, SCN1B, and SCN2B genes in the brain. These play a key role in epilepsy, with the most commonly mutated gene in epilepsy being SCN1A. We examined whether polymorphisms in the above genes affect epilepsy risk in 1,529 epilepsy patients and 1,935 controls from four ethnicities or locations: Malay, Indian, and Chinese, all from Malaysia, and Chinese from Hong Kong. Of patients, 19 % were idiopathic, 42 % symptomatic, and 40 % cryptogenic. We genotyped 43 polymorphisms: 27 in Hong Kong, 28 in Malaysia, and 12 in both locations. The strongest association with epilepsy was rs3812718, or SCN1A IVS5N+5G>A: odds ratio (OR) = 0.85 for allele G (p = 0.0009) and 0.73 for genotype GG versus AA (p = 0.003). The OR was between 0.76 and 0.87 for all ethnicities. Meta-analysis confirmed the association (OR = 0.81 and p = 0.002 for G, and OR = 0.67 and p = 0.007 for GG versus AA), which appeared particularly strong for Indians and for febrile seizures. Allele G affects splicing and speeds recovery from inactivation. Since SCN1A is preferentially expressed in inhibitory neurons, G may decrease epilepsy risk. SCN1A rs10188577 displayed OR = 1.20 for allele C (p = 0.003); SCN2A rs12467383 had OR = 1.16 for allele A (p = 0.01), and displayed linkage disequilibrium with rs2082366 (r (2) = 0.67), whose genotypes tended toward association with SCN2A brain expression (p = 0.10). SCN1A rs2298771 was associated in Indians (OR = 0.56, p = 0.005) and SCN2B rs602594 with idiopathic epilepsy (OR = 0.62, p = 0.002). Therefore, sodium channel polymorphisms are associated with epilepsy.
  15. Paton NI, Gurumurthy M, Lu Q, Leek F, Kwan P, Koh HWL, et al.
    J Infect Dis, 2024 Mar 25.
    PMID: 38527849 DOI: 10.1093/infdis/jiae104
    BACKGROUND: Interleukin-4 (IL-4), increased in tuberculosis infection, may impair bacterial killing. Blocking IL-4 confers benefit in animal models. We evaluated safety and efficacy of pascolizumab (humanised anti-IL-4 monoclonal antibody) as adjunctive tuberculosis treatment.

    METHODS: Participants with rifampicin-susceptible pulmonary tuberculosis received a single intravenous infusion of pascolizumab or placebo; and standard 6-month tuberculosis treatment. Pascolizumab dose increased in successive cohorts: [1] non-randomised 0.05 mg/kg (n = 4); [2] non-randomised 0.5 mg/kg (n = 4); [3] randomised 2.5 mg/kg (n = 9) or placebo (n = 3); [4] randomised 10 mg/kg (n = 9) or placebo (n = 3). Co-primary safety outcome was study-drug-related grade 4 or serious adverse event (G4/SAE); in all cohorts (1-4). Co-primary efficacy outcome was week-8 sputum culture time-to-positivity (TTP); in randomised cohorts (3-4) combined.

    RESULTS: Pascolizumab levels exceeded IL-4 50% neutralising dose for 8 weeks in 78-100% of participants in cohorts 3-4. There were no study-drug-related G4/SAEs. Median week-8 TTP was 42 days in pascolizumab and placebo groups (p = 0.185). Rate of TTP increase was greater with pascolizumab (difference from placebo 0.011 [95% Bayesian credible interval 0.006 to 0.015] log10TTP/day.

    CONCLUSIONS: There was no evidence to suggest blocking IL-4 was unsafe. Preliminary efficacy findings are consistent with animal models. This supports further investigation of adjunctive anti-IL-4 interventions for tuberculosis in larger phase 2 trials.

  16. Shi YW, Min FL, Zhou D, Qin B, Wang J, Hu FY, et al.
    Neurology, 2017 Jun 06;88(23):2183-2191.
    PMID: 28476759 DOI: 10.1212/WNL.0000000000004008
    OBJECTIVE: To investigate the involvement of human leukocyte antigen (HLA) loci in aromatic antiepileptic drug-induced cutaneous adverse reactions.

    METHODS: A case-control study was performed to detect HLA loci involved in aromatic antiepileptic drug-induced Stevens-Johnson syndrome in a southern Han Chinese population. Between January 1, 2006, and December 31, 2015, 91 cases of Stevens-Johnson syndrome induced by aromatic antiepileptic drugs and 322 matched drug-tolerant controls were enrolled from 8 centers. Important genotypes were replicated in cases with maculopapular eruption and in the meta-analyses of data from other populations. Sequence-based typing determined the HLA-A, HLA-B, HLA-C, and HLA-DRB1 genotypes.

    RESULTS: HLA-B*15:02 was confirmed as strongly associated with carbamazepine-induced Stevens-Johnson syndrome (p = 5.63 × 10(-15)). In addition, HLA-A*24:02 was associated significantly with Stevens-Johnson syndrome induced by the aromatic antiepileptic drugs as a group (p = 1.02 × 10(-5)) and by individual drugs (carbamazepine p = 0.015, lamotrigine p = 0.005, phenytoin p = 0.027). Logistic regression analysis revealed a multiplicative interaction between HLA-B*15:02 and HLA-A*24:02. Positivity for HLA-A*24:02 and/or HLA-B*15:02 showed a sensitivity of 72.5% and a specificity of 69.0%. The presence of HLA-A*24:02 in cases with maculopapular exanthema was also significantly higher than in controls (p = 0.023). Meta-analysis of data from Japan, Korea, Malaysia, Mexico, Norway, and China revealed a similar association.

    CONCLUSIONS: HLA-A*24:02 is a common genetic risk factor for cutaneous adverse reactions induced by aromatic antiepileptic drugs in the southern Han Chinese and possibly other ethnic populations. Pretreatment screening is recommended for people in southern China.

  17. Ma RC, Hu C, Tam CH, Zhang R, Kwan P, Leung TF, et al.
    Diabetologia, 2013 Jun;56(6):1291-305.
    PMID: 23532257 DOI: 10.1007/s00125-013-2874-4
    AIMS/HYPOTHESIS: Most genetic variants identified for type 2 diabetes have been discovered in European populations. We performed genome-wide association studies (GWAS) in a Chinese population with the aim of identifying novel variants for type 2 diabetes in Asians.

    METHODS: We performed a meta-analysis of three GWAS comprising 684 patients with type 2 diabetes and 955 controls of Southern Han Chinese descent. We followed up the top signals in two independent Southern Han Chinese cohorts (totalling 10,383 cases and 6,974 controls), and performed in silico replication in multiple populations.

    RESULTS: We identified CDKN2A/B and four novel type 2 diabetes association signals with p p meta = 2.6 × 10(-8); OR [95% CI] 1.18 [1.11, 1.25]). In silico replication revealed consistent associations across multiethnic groups, including five East Asian populations (p meta = 2.3 × 10(-10)) and a population of European descent (p = 8.6 × 10(-3)). The rs10229583 risk variant was associated with elevated fasting plasma glucose, impaired beta cell function in controls, and an earlier age at diagnosis for the cases. The novel variant lies within an islet-selective cluster of open regulatory elements. There was significant heterogeneity of effect between Han Chinese and individuals of European descent, Malaysians and Indians.

    CONCLUSIONS/INTERPRETATION: Our study identifies rs10229583 near PAX4 as a novel locus for type 2 diabetes in Chinese and other populations and provides new insights into the pathogenesis of type 2 diabetes.

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