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Fulltext A Novel Occulta-Type Spina Bifida Mediated by Murine Double Heterozygotes EphA2 and EphA4 Receptor Tyrosine Kinases

Abdullah NL, Mohd-Zin SW, Ahmad-Annuar A, Abdul-Aziz NM

Front Cell Dev Biol, 2017;5:105.
PMID: 29312933 DOI: 10.3389/fcell.2017.00105

Members of the Eph receptor tyrosine kinase have previously been implicated in cranial neural tube development. Failure of neural tube closure leads to the devastating conditions known as anencephaly and spina bifida. EphA2 and EphA4 are expressed at the tips of the closing spinal neural folds prior and during neural tube closure. We investigated the possible role of murine EphA2 and EphA4 during the last step of primary neural tube closure, which is adhesion and fusion. The individual mouse knockouts of EphA2 and EphA4 per se do not exhibit neural tube defects (NTDs). The embryos generated by the crossing of double heterozygotes Epha2tm1Jrui/+Epha4rb-2J/+ displayed NTDs with a wide degree of severity including close exencephaly and close spina bifida (spina bifida occulta). Interestingly, mutants displaying NTDs had skin covering the underlying lesion. The tissue sections revealed the elevated neural folds had not adhered and fused. The phenotypes seen in Epha2tm1Jrui/+Epha4rb-2J/+ double heterozygous embryos suggest both genes play a compensatory role with each other in the adhesion and fusion of the neural tube. In this study, there exists a >50% penetrance of NTDs in the mouse mutants, which genetically have a single allele each of EphA2 and EphA4 absent.
Fulltext A Patient with Beta-Propeller Protein-Associated Neurodegeneration: Treatment with Iron Chelation Therapy

Lim SY, Tan AH, Ahmad-Annuar A, Schneider SA, Bee PC, Lim JL, et al.

J Mov Disord, 2018 May;11(2):89-92.
PMID: 29860786 DOI: 10.14802/jmd.17082

We present a case of beta-propeller protein-associated neurodegeneration, a form of neurodegeneration with brain iron accumulation. The patient harbored a novel mutation in the WDR45 gene. A detailed video and description of her clinical condition are provided. Her movement disorder phenomenology was characterized primarily by limb stereotypies and gait dyspraxia. The patient's disability was advanced by the time iron-chelating therapy with deferiprone was initiated, and no clinical response in terms of cognitive function, behavior, speech, or movements were observed after one year of treatment.
Fulltext A Perspective on the Role of microRNA-128 Regulation in Mental and Behavioral Disorders

Ching AS, Ahmad-Annuar A

Front Cell Neurosci, 2015;9:465.
PMID: 26696825 DOI: 10.3389/fncel.2015.00465

MiRNAs are short, non-coding RNA molecules that regulate gene expression post-transcriptionally. Over the past decade, misregulated miRNA pathways have been associated with various diseases such as cancer, neurodegenerative diseases, and neurodevelopmental disorders. In this article, we aim to discuss the role played by miR-128 in neuropsychiatric disorders, and highlight potential target genes from an in silico analysis of predicted miR-128 targets. We also discuss the differences of target gene determination based on a bioinformatics or empirical approach. Using data from TargetScan and published reports, we narrowed the miR-128 target gene list to those that are known to be associated with neuropsychiatric disorders, and found that these genes can be classified into 29 gene clusters and are mostly enriched in cancer and MAPK signaling pathways. We also highlight some recent studies on several of the miR-128 targets which should be investigated further as potential candidate genes for therapeutic interventions.
Fulltext A survey on patients' disease perception and the impact of the COVID-19 pandemic on persons living with amyotrophic lateral sclerosis in Malaysia

Edgar S, Abdul-Aziz NA, Loh EC, Capelle D, Goh KJ, Latif LA, et al.

Neurodegener Dis Manag, 2021 08;11(4):307-314.
PMID: 34284643 DOI: 10.2217/nmt-2021-0004

Aim: To investigate the patients' perception of their disease, its management and the impact of the COVID-19 pandemic on persons living with amyotrophic lateral sclerosis (ALS) in Malaysia. Patients & methods: An online survey comprising 42 questions was conducted on ALS patients during the peak of the COVID-19 pandemic. Results: Responses were received from 37/60 (62%) participants with ALS directly or through their caregivers. During the COVID-19 pandemic, two-thirds of patients were negatively impacted by the sudden disruption to their hospital appointments, rehabilitation sessions and reduced social interactions. Conclusion: This study provided insight into patients' perception of their care and management of ALS in Malaysia which will facilitate in implementing changes that can improve care to persons living with this devastating illness.
Ala97Ser mutation is common among ethnic Chinese Malaysians with transthyretin familial amyloid polyneuropathy

Low SC, Tan CY, Md Sari NA, Ahmad-Annuar A, Wong KT, Lin KP, et al.

Amyloid, 2019 7 26;26(sup1):7-8.
PMID: 31343308 DOI: 10.1080/13506129.2019.1582479
Fulltext Alternating Hemiplegia of Childhood in a Person of Malay Ethnicity with Diffusion Tensor Imaging Abnormalities

Tan AH, Ong TL, Ramli N, Tan LK, Lim JL, Azhan MA, et al.

J Mov Disord, 2019 May;12(2):132-134.
PMID: 31158946 DOI: 10.14802/jmd.18063
Fulltext Analysis of CTG repeat length variation in the DMPK gene in the general population and the molecular diagnosis of myotonic dystrophy type 1 in Malaysia

Ambrose KK, Ishak T, Lian LH, Goh KJ, Wong KT, Ahmad-Annuar A, et al.

BMJ Open, 2017 03 31;7(3):e010711.
PMID: 28363916 DOI: 10.1136/bmjopen-2015-010711

OBJECTIVE: The lack of epidemiological data and molecular diagnostic services in Malaysia has hampered the setting-up of a comprehensive management plan for patients with myotonic dystrophy type 1 (DM1), leading to delayed diagnosis, treatment and support for patients and families. The aim of this study was to estimate the prevalence of DM1 in the 3 major ethnic groups in Malaysia and evaluate the feasibility of a single tube triplet-primed PCR (TP-PCR) method for diagnosis of DM1 in Malaysia.
DESIGN, SETTING AND PARTICIPANTS: We used PCR to determine the size of CTG repeats in 377 individuals not known to be affected by DM and 11 DM1 suspected patients, recruited from a tertiary hospital in Kuala Lumpur. TP-PCR was performed on selected samples, followed by Southern blot hybridisation of PCR amplified fragments to confirm and estimate the size of CTG expansion.
OUTCOME MEASURES: The number of individuals not known to be affected by DM with (CTG)>18 was determined according to ethnic group and as a whole population. The χ2 test was performed to compare the distribution of (CTG)>18 with 12 other populations. Additionally, the accuracy of TP-PCR in detecting CTG expansion in 11 patients with DM1 was determined by comparing the results with that from Southern blot hybridisation.
RESULTS: Of the 754 chromosomes studied, (CTG)>18 frequency of 3.60%, 1.57% and 4.00% in the Malay, Chinese and Indian subpopulations, respectively, was detected, showing similarities to data from Thai, Taiwanese and Kuwaiti populations. We also successfully detected CTG expansions in 9 patients using the TP-PCR method followed by the estimation of CTG expansion size via Southern blot hybridisation.
CONCLUSIONS: The results show a low DM1 prevalence in Malaysia with the possibility of underdiagnosis and demonstrates the feasibility of using a clinical and TP-PCR-based approach for rapid and cost-effective DM1 diagnosis in developing countries.
Analysis of dynein intermediate chains, light intermediate chains and light chains in a cohort of hereditary peripheral neuropathies

Tey S, Ahmad-Annuar A, Drew AP, Shahrizaila N, Nicholson GA, Kennerson ML

Neurogenetics, 2014 Oct;15(4):229-35.
PMID: 25028179 DOI: 10.1007/s10048-014-0414-0

The cytoplasmic dynein heavy chain (DYNC1H1) gene has been increasingly associated with neurodegenerative disorders including axonal Charcot-Marie-Tooth disease (CMT2), intellectual disability and malformations of cortical development. In addition, evidence from mouse models (Loa, catabolite repressor-activator (Cra) and Sprawling (Swl)) has shown that mutations in Dync1h1 cause a range of neurodegenerative phenotypes with motor and sensory neuron involvement. In this current study, we examined the possible contribution of other cytoplasmic dynein subunits that bind to DYNC1H1 as a cause of inherited peripheral neuropathy. We focused on screening the cytoplasmic dynein intermediate, light intermediate and light chain genes in a cohort of families with inherited peripheral neuropathies. Nine genes were screened and ten variants were detected, but none was identified as pathogenic, indicating that cytoplasmic dynein intermediate, light intermediate and light chains are not a cause of neuropathy in our cohort.
Fulltext Analysis of non-synonymous-coding variants of Parkinson's disease-related pathogenic and susceptibility genes in East Asian populations

Foo JN, Tan LC, Liany H, Koh TH, Irwan ID, Ng YY, et al.

Hum Mol Genet, 2014 Jul 15;23(14):3891-7.
PMID: 24565865 DOI: 10.1093/hmg/ddu086

To evaluate the contribution of non-synonymous-coding variants of known familial and genome-wide association studies (GWAS)-linked genes for Parkinson's disease (PD) to PD risk in the East Asian population, we sequenced all the coding exons of 39 PD-related disease genes and evaluated the accumulation of rare non-synonymous-coding variants in 375 early-onset PD cases and 399 controls. We also genotyped 782 non-synonymous-coding variants of these genes in 710 late-onset PD cases and 9046 population controls. Significant enrichment of LRRK2 variants was observed in both early- and late-onset PD (odds ratio = 1.58; 95% confidence interval = 1.29-1.93; P = 8.05 × 10(-6)). Moderate enrichment was also observed in FGF20, MCCC1, GBA and ITGA8. Half of the rare variants anticipated to cause loss of function of these genes were present in healthy controls. Overall, non-synonymous-coding variants of known familial and GWAS-linked genes appear to make a limited contribution to PD risk, suggesting that clinical sequencing of these genes will provide limited information for risk prediction and molecular diagnosis.
Fulltext Association of LRRK2 Haplotype With Age at Onset in Parkinson Disease

Xiao B, Deng X, Ng EY, Allen JC, Lim SY, Ahmad-Annuar A, et al.

JAMA Neurol, 2018 01 01;75(1):127-128.
PMID: 29131875 DOI: 10.1001/jamaneurol.2017.3363
Association study of MCCC1/LAMP3 and DGKQ variants with Parkinson's disease in patients of Malay ancestry

Lim JL, Ng EY, Lim SY, Tan AH, Abdul-Aziz Z, Ibrahim KA, et al.

Neurol Sci, 2021 Oct;42(10):4203-4207.
PMID: 33559030 DOI: 10.1007/s10072-021-05056-x

BACKGROUND: Genome-wide association studies (GWAS) have shown that variants in the 3-methylcrotonyl-CoA carboxylase (MCCC1)/lysosome-associated membrane protein 3 (LAMP3) loci (rs10513789, rs12637471, rs12493050) reduce the risk of Parkinson's disease (PD) in Caucasians, Chinese and Ashkenazi-Jews while the rs11248060 variant in the diacylglycerol kinase theta (DGKQ) gene increases the risk of PD in Caucasian and Han Chinese cohorts. However, their roles in Malays are unknown. Therefore, this study aims to investigate the association of these variants with the risk of PD in individuals of Malay ancestry.
METHODS: A total of 1114 subjects comprising of 536 PD patients and 578 healthy controls of Malay ancestry were recruited and genotyped using Taqman® allelic discrimination assays.
RESULTS: The G allele of rs10513789 (OR = 0.83, p = 0.001) and A allele of rs12637471 (OR = 0.79, p = 0.007) in the MCCC1/LAMP3 locus were associated with a protective effect against developing PD in the Malay population. A recessive model of penetrance showed a protective effect of the GG genotype for rs10513789 and the AA genotype for rs12637471. No association with PD was found with the other MCCC1/LAMP3 rs12493050 variant or with the DGKQ (rs11248060) variant. No significant associations were found between the four variants with the age at PD diagnosis.
CONCLUSION: MCCC1/LAMP3 variants rs10513789 and rs12637471 protect against PD in the Malay population.
Fulltext COVID-19 pandemic: Lessons learned for undergraduate research training

Ibrahim K, Ahmad-Annuar A

Biochem Mol Biol Educ, 2022 09;50(5):476-478.
PMID: 36054325 DOI: 10.1002/bmb.21665

This article reports a session from the virtual international 2021 IUBMB/ASBMB workshop, "Teaching Science on Big Data." The awareness of using publicly available research data sets for undergraduate training is low in certain parts of the world. Final year projects always revolve around wet-lab based projects. The challenges occur during COVID-19 pandemic when it forces full lockdown to the nation, but at the same time faculty members need to provide consistent training to the students and projects to work with. We aim to identify supervisors in the faculty that are ready to convert their proposed project from wet-lab to an online-based project. As coordinators of the course we created an online survey to identify projects that can be converted into dry-lab/online projects. Our surveys identified only 32.5% projects implemented dry-lab/online based projects. Most academicians described that they are not ready or familiar to apply changes for their research design. With the unknown future of the world living with COVID-19 and directional changes of life science research toward big data driven research indeed we should be ready to adopt such changes. Awareness on reusing public data sets as tools for research should be provided to strengthen undergraduate training. Life science undergraduates should be exposed to reusing public data sets as these materials are readily available case studies that allow in depth exploration to answer specific research questions. Members of the faculty should take part to pave the way for them, ensuring that they understand that life science research revolves around a multidisciplinary field.
Fulltext Clinical Phenotype of LRRK2 R1441C in 2 Chinese Sisters

Lim SY, Lim JL, Ahmad-Annuar A, Lohmann K, Tan AH, Lim KB, et al.

Neurodegener Dis, 2020;20(1):39-45.
PMID: 32580205 DOI: 10.1159/000508131

Pathogenic and risk variants in the LRRK2 gene are among the main genetic contributors to Parkinson's disease (PD) worldwide, and LRRK2-targeted therapies for patients with PARK-LRRK2are now entering clinical trials. However, in contrast to the LRRK2 G2019S mutation commonly found in Caucasians, North-African Arabs, and Ashkenazi Jews, relatively little is known about other causative LRRK2 mutations, and data on genotype-phenotype correlations are largely lacking. This report is from an ongoing multicentre study in which next-generation sequencing-based PD gene panel testing has so far been conducted on 499 PD patients of various ethnicities from Malaysia. We describe 2 sisters of Chinese ancestry with PD who carry the R1441C mutation in LRRK2 (which in Asians has been reported in only 2 Chinese patients previously), and highlight interesting clinical observations made over a decade of close follow-up. We further explored the feasibility of using a brief, expert-administered rating scale (the Clinical Impression of Severity Index; CISI-PD) to capture data on global disease severity in a large (n = 820) unselected cohort of PD patients, including severely disabled individuals typically excluded from research studies. All patients in this study were managed and evaluated by the same PD neurologist, and these data were used to make broad comparisons between the monogenic PD cases versus the overall "real world" PD cohort. This report contributes to the scarce literature on R1441C PARK-LRRK2, offering insights into natural history and epidemiological aspects, and provides support for the application of a simple and reliable clinical tool that can improve the inclusion of under-represented patient groups in PD research.
Congenital myasthenic syndrome due to novel CHAT mutations in an ethnic kadazandusun family

Tan JS, Ambang T, Ahmad-Annuar A, Rajahram GS, Wong KT, Goh KJ

Muscle Nerve, 2016 May;53(5):822-826.
PMID: 26789281 DOI: 10.1002/mus.25037

Choline acetyltransferase (CHAT) gene mutations cause a rare presynaptic congenital myasthenic syndrome due to impaired acetylcholine resynthesis.
Fulltext Cranial neural tube defect after trimethoprim exposure

Abdullah NL, Gunasekaran R, Mohd-Zin SW, Lim BH, Maniam P, Mohd-Salleh AS, et al.

BMC Res Notes, 2018 Jul 16;11(1):475.
PMID: 30012199 DOI: 10.1186/s13104-018-3593-1

OBJECTIVES: The Neural Tube Defects Research Group of University of Malaya was approached to analyze a tablet named TELSE, which may have resulted in a baby born with central nervous system malformation at the University of Malaya Medical Centre. In this animal experimental study, we investigated the content of TELSE and exposure of its contents that resulted in failure of primary neurulation.
RESULTS: Liquid Chromatography Tandem Mass spectrophotometry analysis of the TELSE tablet confirmed the presence of trimethoprim as the active compound. The TELSE tablet-treated females produced significant numbers of embryos with exencephaly (n = 8, 36.4%, *P
Fulltext DRD and GRIN2B polymorphisms and their association with the development of impulse control behaviour among Malaysian Parkinson's disease patients

Zainal Abidin S, Tan EL, Chan SC, Jaafar A, Lee AX, Abd Hamid MH, et al.

BMC Neurol, 2015;15:59.
PMID: 25896831 DOI: 10.1186/s12883-015-0316-2

Impulse control disorder (ICD) and behaviours (ICB) represent a group of behavioural disorders that have become increasingly recognised in Parkinson's disease (PD) patients who previously used dopaminergic medications, particularly dopamine agonists and levodopa. It has been suggested that these medications can lead to the development of ICB through the abnormal modulation of dopaminergic transmission and signalling in the mesocorticolimbic dopaminergic system. Several studies have reported an association between polymorphisms in the dopamine receptor (DRD) and N-methyl-D-aspartate 2B (GRIN2B) genes with the development of ICB in PD (PD-ICB) patients. Thus, this study aimed to investigate the association of selected polymorphisms within the DRD and GRIN2B genes with the development of ICB among PD patients using high resolution melt (HRM) analysis.
Fulltext DTI Profiles for Rapid Description of Cohorts at the Clinical-Research Interface

Lock C, Kwok J, Kumar S, Ahmad-Annuar A, Narayanan V, Ng ASL, et al.

Front Med (Lausanne), 2018;5:357.
PMID: 30687707 DOI: 10.3389/fmed.2018.00357

Normal pressure hydrocephalus (NPH) is a syndrome comprising gait disturbance, cognitive decline and urinary incontinence that is an unique model of reversible brain injury, but it presents as a challenging spectrum of disease cohorts. Diffusion Tensor Imaging (DTI), with its ability to interrogate structural white matter patterns at a microarchitectural level, is a potentially useful tool for the confirmation and characterization of disease cohorts at the clinical-research interface. However, obstacles to its widespread use involve the need for consistent DTI analysis and interpretation tools across collaborator sites. We present the use of DTI profiles, a simplistic methodology to interpret white matter injury patterns based on the morphology of diffusivity parameters. We examined 13 patients with complex NPH, i.e., patients with NPH and overlay from multiple comorbidities, including vascular risk burden and neurodegenerative disease, undergoing extended CSF drainage, clinical assessments, and multi-modal MR imaging. Following appropriate exclusions, we compared the morphology of DTI profiles in such complex NPH patients (n = 12, comprising 4 responders and 8 non-responders) to exemplar DTI profiles from a cohort of classic NPH patients (n = 16) demonstrating responsiveness of white matter injury to ventriculo-peritoneal shunting. In the cohort of complex NPH patients, mean age was 71.3 ± 7.6 years (10 males, 2 females) with a mean MMSE score of 21.1. There were 5 age-matched healthy controls, mean age was 73.4 ± 7.2 years (1 male, 4 females) and mean MMSE score was 26.8. In the exemplar cohort of classic NPH patients, mean age was 74.7 ± 5.9 years (10 males, 6 females) and mean MMSE score was 24.1. There were 9 age-matched healthy controls, mean age was 69.4 ± 9.7 years (4 males, 5 females) and mean MMSE score was 28.6. We found that, despite the challenges of acquiring DTI metrics from differing scanners across collaborator sites and NPH patients presenting as differing cohorts along the spectrum of disease, DTI profiles for responsiveness to interventions were comparable. Distinct DTI characteristics were demonstrated for complex NPH responders vs. non-responders. The morphology of DTI profiles for complex NPH responders mimicked DTI patterns found in predominantly shunt-responsive patients undergoing intervention for classic NPH. However, DTI profiles for complex NPH non-responders was suggestive of atrophy. Our findings suggest that it is possible to use DTI profiles to provide a methodology for rapid description of differing cohorts of disease at the clinical-research interface. By describing DTI measures morphologically, it was possible to consistently compare white matter injury patterns across international collaborator datasets.
Fulltext Deregulation of microRNAs in blood and skeletal muscles of myotonic dystrophy type 1 patients

Ambrose KK, Ishak T, Lian LH, Goh KJ, Wong KT, Ahmad-Annuar A, et al.

Neurol India, 2017 5 11;65(3):512-517.
PMID: 28488611 DOI: 10.4103/neuroindia.NI_237_16

INTRODUCTION: MicroRNAs (miRNAs) are short RNA molecules of approximately 22 nucleotides that function as post-transcriptional regulators of gene expression. They are expressed in a tissue-specific manner and show different expression patterns in development and disease; hence, they can potentially act as disease-specific biomarkers. Several miRNAs have been shown to be deregulated in plasma and skeletal muscles of myotonic dystrophy type 1 (DM1) patients.
METHODS: We evaluated the expression patterns of 11 candidate miRNAs using quantitative real-time PCR in whole blood (n = 10) and muscle biopsy samples (n = 9) of DM1 patients, and compared them to those of normal control samples (whole blood, n = 10; muscle, n = 9).
RESULTS: In DM1 whole blood, miRNA-133a, -29b, and -33a were significantly upregulated, whereas miRNA-1, -133a, and -29c were significantly downregulated in the skeletal muscles compared to controls.
CONCLUSIONS: Our findings align to those reported in other studies and point towards pathways that potentially contribute toward pathogenesis in DM1. However, the currently available data is not sufficient for these miRNAs to be made DM1-specific biomarkers because they seem to be common to many muscle pathologies. Hence, they lack specificity, but reinforce the need for further exploration of DM1 biomarkers.
Fulltext Editorial: Genetic and molecular diversity in Parkinson's disease

Abdul Murad NA, Sulaiman SA, Ahmad-Annuar A, Mohamed Ibrahim N, Mohamed W, Md Rani SA, et al.

Front Aging Neurosci, 2022;14:1094914.
PMID: 36589546 DOI: 10.3389/fnagi.2022.1094914
Embracing Monogenic Parkinson's Disease: The MJFF Global Genetic PD Cohort

Vollstedt EJ, Schaake S, Lohmann K, Padmanabhan S, Brice A, Lesage S, et al.

Mov Disord, 2023 Feb;38(2):286-303.
PMID: 36692014 DOI: 10.1002/mds.29288

BACKGROUND: As gene-targeted therapies are increasingly being developed for Parkinson's disease (PD), identifying and characterizing carriers of specific genetic pathogenic variants is imperative. Only a small fraction of the estimated number of subjects with monogenic PD worldwide are currently represented in the literature and availability of clinical data and clinical trial-ready cohorts is limited.
OBJECTIVE: The objectives are to (1) establish an international cohort of affected and unaffected individuals with PD-linked variants; (2) provide harmonized and quality-controlled clinical characterization data for each included individual; and (3) further promote collaboration of researchers in the field of monogenic PD.
METHODS: We conducted a worldwide, systematic online survey to collect individual-level data on individuals with PD-linked variants in SNCA, LRRK2, VPS35, PRKN, PINK1, DJ-1, as well as selected pathogenic and risk variants in GBA and corresponding demographic, clinical, and genetic data. All registered cases underwent thorough quality checks, and pathogenicity scoring of the variants and genotype-phenotype relationships were analyzed.
RESULTS: We collected 3888 variant carriers for our analyses, reported by 92 centers (42 countries) worldwide. Of the included individuals, 3185 had a diagnosis of PD (ie, 1306 LRRK2, 115 SNCA, 23 VPS35, 429 PRKN, 75 PINK1, 13 DJ-1, and 1224 GBA) and 703 were unaffected (ie, 328 LRRK2, 32 SNCA, 3 VPS35, 1 PRKN, 1 PINK1, and 338 GBA). In total, we identified 269 different pathogenic variants; 1322 individuals in our cohort (34%) were indicated as not previously published.
CONCLUSIONS: Within the MJFF Global Genetic PD Study Group, we (1) established the largest international cohort of affected and unaffected individuals carrying PD-linked variants; (2) provide harmonized and quality-controlled clinical and genetic data for each included individual; (3) promote collaboration in the field of genetic PD with a view toward clinical and genetic stratification of patients for gene-targeted clinical trials. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

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