Publications by authors named "Ngai Chuen Sin"

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.

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In the majority of patients, epilepsy is a complex disorder with multiple susceptibility genes interacting with environmental factors. However, we understand little about its genetic risks. Here, we report the first genome-wide association study (GWAS) to identify common susceptibility variants of epilepsy in Chinese.

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Aim: To determine the association between polymorphisms of the multidrug transporter genes ABCC2, ABCC5 and ABCG2, and drug resistance in epilepsy by genotyping comprehensive sets of tagging SNPs.

Materials & Methods: A total of 25 tagging SNPs from ABCC2, ABCC5 and ABCG2 genes were genotyped in a total of 590 Han Chinese epilepsy patients (262 drug resistant and 328 drug responsive). Genotype and allele distributions in drug-responsive and drug-resistant patients were compared.

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Arecent study in Caucasians found an association between the single nucleotide polymorphism (SNP) of SCN1A, IVS5N +5 G>A (rs3812718), and febrile seizures (FS). We examined whether this and other tagging SNPs of SCN1A were associated with an increased risk of FS in Han Chinese. A total of 728 Han Chinese patients with focal epilepsy were recruited: 97 had a history of FS (58% male, mean age 35 ± 12 years) and 631 did not (50% male, mean age 40 ± 15 years).

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Aims: It remains controversial whether polymorphisms of the multidrug resistance gene ABCB1 are associated with pharmacoresistance in epilepsy. To further study the potential association, we genotyped a broad set of tagging SNPs, and explored whether any associations were affected by other host factors. We correlated any association with cerebral mRNA expression of ABCB1.

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Objectives: Many antiepileptic drugs (AEDs) prevent seizures by blocking voltage-gated brain sodium channels. However, treatment is ineffective in 30% of epilepsy patients, which might, at least in part, result from polymorphisms of the sodium channel genes. We investigated the association of AED responsiveness with genetic polymorphisms and correlated any association with mRNA expression of the neuronal sodium channels.

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There is accumulating evidence to suggest that overexpression of efflux drug transporters at the blood-brain barrier, by reducing antiepileptic drug (AED) accumulation in the seizure foci, contributes to drug resistance in epilepsy. P-glycoprotein, encoded by the ABCB1 gene, is the most studied drug transporter. There are conflicting data as to whether the CC genotype of the ABCB1 3435C>T polymorphism is associated with drug resistance in Caucasian patients with epilepsy.

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Objective: This was a prospective open study to establish the efficacy, tolerability, and problems associated with the use of topiramate as first-choice drug in children with infantile spasms.

Methods: Open-label follow-up study, ranging from 24 to 36 months, of the cases of 54 patients with infantile spasms treated initially with topiramate as first-choice drug.

Results: Thirty-one patients (57.

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An 11-year-old boy developed severe hypersensitivity reaction to phenobarbitone resulted in fulminant hepatic failure. During the course of illness, he developed clinical features compatible with severe acute respiratory syndrome (SARS) that may have complicated the recovery of his underlying hypersensitivity reaction, which was subsequently controlled with intravenous immune globulin and corticosteroids.

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