1.Multiple Acyl-CoA Dehydrogenase Deficiency: Phenotypic and Genetic Features of a Malaysian Cohort
Jie Ping SCHEE ; Joo San TAN ; Cheng Yin TAN ; Nortina SHAHRIZAILA ; Kum Thong WONG ; Khean Jin GOH
Journal of Clinical Neurology 2024;20(4):422-430
Background:
and Purpose Multiple acyl-CoA dehydrogenase deficiency (MADD) is an inherited disorder of fatty acid oxidation that causes lipid storage myopathy (LSM). This is the first report on MADD that describes the phenotypic and genetic features of a Malaysian cohort.
Methods:
Among the >2,500 patients in a local muscle biopsy database, patients with LSM were identified and their genomic DNA were extracted from muscle samples and peripheral blood.All 13 exons of the electron-transfer flavoprotein dehydrogenase gene (ETFDH) were subsequently sequenced. Fifty controls were included to determine the prevalence of identified mutations in the normal population.
Results:
Fourteen (82%) of the 17 LSM patients had MADD with ETFDH mutations. Twelve (86%) were Chinese and two were Malay sisters. Other unrelated patients reported that they had no relevant family history. Nine (64%) were females. The median age at onset was 18.5 years (interquartile range=16–37 years). All 14 demonstrated proximal limb weakness, elevated serum creatine kinase levels, and myopathic changes in electromyography. Three patients experienced a metabolic crisis at their presentation. Sanger sequencing of ETFDH revealed nine different variants/mutations, one of which was novel: c.998A>G (p.Y333C) in exon 9. Notably, 12 (86%) patients, including the 2 Malay sisters, carried a common c.250G>A (p.A84T) variant, consistent with the hotspot mutation reported in southern China. All of the patients responded well to riboflavin therapy.
Conclusions
Most of our Malaysian cohort with LSM had late-onset, riboflavin-responsive MADD with ETFDH mutations, and they demonstrated phenotypic and genetic features similar to those of cases reported in southern China. Furthermore, we report a novel ETFDH mutation and possibly the first ever MADD patients of Malay descent.
2.Japanese encephalitis virus: Biological clones from a clinical isolate quasispecies show differing neurovirulence in vitro and in a mouse model
Shu Pin Yu ; Kien Chai Ong ; Soon Hao Tan ; David Perera ; Kum Thong Wong
Neurology Asia 2020;25(3):279-284
The Japanese encephalitis virus (JEV), a leading cause of encephalitis, exists as quasispecies in clinical
isolates. Using a limiting dilution method combined with immunohistochemistry to detect viral antigens,
10 biological clones were isolated and purified from a clinical JEV isolate (CNS138/9) derived from
an autopsy brain. These biological clones were tested for neurovirulence in SK-N-MC and NIE-115
neuronal cells, and a 2-week-old, footpad-infected, JE mouse model. Nine clones were found to be
neurovirulent; one clone neuroattenuated. Although further studies are needed to determine genotypic
differences, if any, in these clones, the limiting dilution purification and neurovirulence testing methods
described herein should be useful for phenotypic studies of quasispecies of neurotropic viruses in
general, and JEV and other flaviviruses in particular.
3.Level 4 comprehensive epilepsy program in Malaysia, a resource-limited country
Kheng-Seang LIM ; Sherrini Ahmad Bazir Ahmad ; Vairavan NARAYANAN ; Kartini RAHMAT ; Norlisah Mohd RAMLI ; Kein-Seong MUN ; Kum-Thong WONG ; Noraini ISMAIL ; Shweh-Fern LOO ; Chong-Tin TAN
Neurology Asia 2017;22(4):299-305
Background and Objective: There is a great challenge to establish a level 4 epilepsy care offeringcomplete evaluation for epilepsy surgery including invasive monitoring in a resource-limited country.This study aimed to report the setup of a level 4 comprehensive epilepsy program in Malaysia and theoutcome of epilepsy surgery over the past 4 years. Methods: This is a retrospective study analyzingcases with intractable epilepsy in a comprehensive epilepsy program in University Malaya MedicalCenter (UMMC), Kuala Lumpur, from January 2012 to August 2016. Results: A total of 92 caseshad comprehensive epilepsy evaluation from January 2012 till August 2016. The mean age was 35.57years old (range 15-59) and 54 (58.7%) were male. There were 17 cases having epilepsy surgeryafter stage-1 evaluation. Eleven cases had mesial temporal sclerosis and 81% achieved Engel classI surgical outcome. Six cases had lesionectomy and 60% had Engel class I outcome. A total of 16surgeries were performed after stage-2 evaluation, including invasive EEG monitoring in 9 cases.Among those with surgery performed more than 12 months from the time of data collection, 5/10(50%) achieved Engel I outcome, whereas 2 (20%) had worthwhile improvement (Engel class III)with 75% and 90% seizure reduction.Conclusion: Level 4 epilepsy care has an important role and is possible with joint multidisciplinaryeffort in a middle-income country like Malaysia despite resource limitation.
4.Primary angiitis of the central nervous system with myelopathy as initial clinical presentation
Cheng Yin Tan ; Ganeshwara Lingam ; Kartini Rahmat ; Suhailah Abdullah ; Ai Huey Tan ; Mei-Ling Sharon Tai ; Norlisah Ramli ; Wong Kum Thong ; Chong Tin Tan
Neurology Asia 2015;20(1):79-84
Primary angiitis of the central nervous system (PACNS) is a rare vasculitis restricted to the central
nervous system without systemic involvement. Delay in diagnosis and treatment is common due to its
non-specific symptoms and lack of non-invasive diagnostic tests. Myelopathy can occur in PACNS,
during the clinical course of the illness, with or without cerebral symptoms. We describe here a 51
year-old ethnic Chinese woman who presented initially with paraparesis without cerebral symptoms.
The diagnosis of PACNS was eventually made from brain biopsy when she subsequently developed
cerebral involvement. Despite aggressive treatment, the patient developed progressive neurological
deterioration and died. This patient demonstrates the rare occurrence of myelopathy as the sole initial
presentation of PACNS.
Central Nervous System
;
Spinal Cord Diseases
5.Pathological findings in a mouse model for Coxsackievirus A16 infection
Yuan Teng Hooi ; Kien Chai Ong ; David Perera ; Kum Thong Wong
Neurology Asia 2015;20(3):343-347
Coxsackievirus A16 (CV-A16) is the leading cause of hand-foot-mouth disease (HFMD), which usually
presents as mild and self-limiting symptoms in young children. Rarely, CV-A16 has been reported
to cause severe and fatal neurological complications but little is known about these complications.
In the present study, 1-day and 7-day old mouse models of CV-A16 were developed using a clinical
strain via subcutaneous inoculation. All infected mice exhibited clinical signs of infection, including
reduced mobility, limb weakness and paralysis between 3 to 6 days post-infection. Pathologically,
the main organs involved were the central nervous system (CNS), skeletal muscles and brown fat. In
the CNS, viral antigens as demonstrated by immunohistochemistry, were localized mainly to neurons
in the brain stem and spinal cord, suggesting that CV-A16 is neurotropic although inflammation is
very mild. The skeletal muscles showed necrosis and myositis due to viral infection as evidenced by
the dense viral antigens. Focal viral antigens were also detected in the brown fat. These preliminary
pathological findings indicate that our mouse models can be further developed to be useful models
for pathogenesis studies, and vaccine and anti-viral drug evaluation.
6.Pathological findings in a mouse model of Japanese encephalitis infected via the footpad
Tzeh Long Fu ; Kien Chai Ong ; Kum Thong Wong
Neurology Asia 2015;20(3):349-354
We have developed and characterised a mouse model of Japanese encephalitis virus (JEV) infection via
footpad inoculation in order to better mimic viral transmission by mosquito bites. Two-week-old and
5-week-old mice consistently developed signs of infection such as ruffled fur, weight loss, hunchback
posture, tremors, mask-like facies and occasionally, hindlimb paralysis at 4 days post infection (dpi)
and 11-13 dpi, respectively. Most of the animals died within 24 to 48 hours following the onset of signs
of infection, with mortalities of 100% and 33.3% in 2-week-old and 5-week-old mice, respectively.
Mild meningitis and variable parenchymal inflammation with formation of microglial nodules, focal
necrosis and neuronophagia, and perivascular cuffing by inflammatory cells were observed in the
caudate nucleus, putamen, thalamus, cerebral cortex, brainstem, and spinal cord. Viral antigens/RNA
were demonstrated by immunohistochemisty and in situ hybridization, respectively, in most of these
areas as well as in the hippocampus and cerebellum, albeit more focally. The pathological findings in
this mouse model were generally similar to human Japanese encephalitis (JE) and other established JE
models but perhaps, compared to other JEV mouse models, it demonstrates lethal encephalitic infection
more consistently. We believe that our mouse model should be useful to study the pathogenesis of JE,
and for testing anti-viral drugs and vaccines
7.Pathological findings in a mouse model for Coxsackievirus A16 infection
Yuan Teng Hooi ; Kien Chai Ong ; David Perera ; Kum Thong Wong
Neurology Asia 2015;20(4):343-347
Coxsackievirus A16 (CV-A16) is the leading cause of hand-foot-mouth disease (HFMD), which usually
presents as mild and self-limiting symptoms in young children. Rarely, CV-A16 has been reported
to cause severe and fatal neurological complications but little is known about these complications.
In the present study, 1-day and 7-day old mouse models of CV-A16 were developed using a clinical
strain via subcutaneous inoculation. All infected mice exhibited clinical signs of infection, including
reduced mobility, limb weakness and paralysis between 3 to 6 days post-infection. Pathologically,
the main organs involved were the central nervous system (CNS), skeletal muscles and brown fat. In
the CNS, viral antigens as demonstrated by immunohistochemistry, were localized mainly to neurons
in the brain stem and spinal cord, suggesting that CV-A16 is neurotropic although inflammation is
very mild. The skeletal muscles showed necrosis and myositis due to viral infection as evidenced by
the dense viral antigens. Focal viral antigens were also detected in the brown fat. These preliminary
pathological findings indicate that our mouse models can be further developed to be useful models
for pathogenesis studies, and vaccine and anti-viral drug evaluation.
Coxsackievirus Infections
8.Pathological findings in a mouse model of Japanese encephalitis infected via the footpad
Tzeh Long Fu ; Kien Chai Ong ; Kum Thong Wong
Neurology Asia 2015;20(4):349-354
We have developed and characterised a mouse model of Japanese encephalitis virus (JEV) infection via
footpad inoculation in order to better mimic viral transmission by mosquito bites. Two-week-old and
5-week-old mice consistently developed signs of infection such as ruffled fur, weight loss, hunchback
posture, tremors, mask-like facies and occasionally, hindlimb paralysis at 4 days post infection (dpi)
and 11-13 dpi, respectively. Most of the animals died within 24 to 48 hours following the onset of signs
of infection, with mortalities of 100% and 33.3% in 2-week-old and 5-week-old mice, respectively.
Mild meningitis and variable parenchymal inflammation with formation of microglial nodules, focal
necrosis and neuronophagia, and perivascular cuffing by inflammatory cells were observed in the
caudate nucleus, putamen, thalamus, cerebral cortex, brainstem, and spinal cord. Viral antigens/RNA
were demonstrated by immunohistochemisty and in situ hybridization, respectively, in most of these
areas as well as in the hippocampus and cerebellum, albeit more focally. The pathological findings in
this mouse model were generally similar to human Japanese encephalitis (JE) and other established JE
models but perhaps, compared to other JEV mouse models, it demonstrates lethal encephalitic infection
more consistently. We believe that our mouse model should be useful to study the pathogenesis of JE,
and for testing anti-viral drugs and vaccines
Encephalitis, Japanese
;
Virus Diseases
9.Single mitochondrial DNA deletions in chronic progressive external ophthalmoplegia (CPEO) and Kearns-Sayre syndrome (KSS) patients from a multiethnic Asian population
Jia-Woei Chong ; Azlina Ahmad Annuar ; Kum-Thong Wong ; Meow-Keong Thong ; Khean-Jin Goh
Neurology Asia 2014;19(1):27-36
Mitochondrial DNA (mtDNA) deletions are a major cause of chronic progressive external ophthalmoplegia
(CPEO) and Kearns-Sayre syndrome (KSS). We analyzed single mtDNA deletions in 11 CPEO and
one KSS patients by means of Southern blot and long polymerase chain reaction (PCR) assays. The
deletion sizes ranged from 3.4 kb to 6.9 kb whereas the heteroplasmy level varied from 18.8% to
85.5%. Two unique deletions sized 4320 bp and 4717 bp were found. This study represents the first
genetic screen of mtDNA disorders in Malaysia, and it follows the data seen in other published reports
on CPEO and KSS genetic aetiology.
10.Cognitive impairments in mild traumatic brain injury apolipoprotein E: A preliminary study in a Level I trauma center
Vigneswaran Veeramuthu ; Devaraj Pancharatnam MSurg ; Anada Raj Poovindran ; Nur Atikah Musthapha ; Wong Kum Thong ; Mazlina Mazlah ; Vicknes Waran ; Dharmendra Ganesan
Neurology Asia 2014;19(1):69-77
The complex pathophysiology of traumatic brain injury, its cascading effects and a varied outcome
suggest that factors such as genetics may permeate and modulate the neurocognitive outcomes
in patients with mild traumatic brain injury (mTBI). This study was conducted to determine the
relationship between genetic polymorphism of apolipoprotein E, and neurocognitive and functional
outcomes in mTBI. Twenty-one patients with mTBI were recruited prospectively. The severity of the
injury was established with the Glasgow Coma Score (GCS). Other assessments included the CT Scan
of the head on admission, Disability Rating Scale, Chessington Occupational Therapy Neurological
Assessment (COTNAB) and Glasgow Outcome Scale (GOS). The Spearmen correlation analysis
of ApoE allele status and the cognitive and functional assessments saw some association with the
Sensory Motor Ability - Coordination (-0.526, p<0.05), Communication Ability (-0.651, p<0.05),
and the Employability (Return to Work) at 1st month (0.455, p<0.05). Notably, the deficits of specific
attributes of visuospatial and sensory motor function were seen with greater impairment consistently
observed in patients with ApoE e4 allele. In conclusion, the preliminary findings support the possible
relationship that exists between ApoE e4 and neurocognitive impairment in mTBI, despite good
functional recovery in 6 months post injury.


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