Papers by Thien Thien Lim
Annals of the Academy of Medicine, Singapore, 2013
The G2385R and R1628P LRRK2 gene variants have been associated with an increased risk of Parkinso... more The G2385R and R1628P LRRK2 gene variants have been associated with an increased risk of Parkinson's disease (PD) in the Asian population. Recently, a new LRRK2 gene variant, A419V, was reported to be a third risk variant for PD in Asian patients. Our objective was to investigate this finding in our cohort of Asian subjects. Eight hundred and twenty-eight subjects (404 PD patients, and 424 age and gender-matched control subjects without neurological disorders) were recruited. Genotyping was done by Taqman® allelic discrimination assay on an Applied Biosystems 7500 Fast Real-Time PCR machine. The heterozygous A419V genotype was found in only 1 patient with PD, compared to 3 in the control group (0.4% vs 1.3%), giving an odds ratio of 0.35 (95% confidence interval (CI), 0.01 to 3.79; P = 0.624). A419V is not an important LRRK2 risk variant in our Asian cohort of patients with PD. Our data are further supported by a literature review which showed that 4 out of 6 published studies r...
BioMed research international, 2014
The LRRK2 gene has been associated with both familial and sporadic forms of…
Annals of the Academy of Medicine, Singapore, 2013
The G2385R and R1628P LRRK2 gene variants have been associated with an increased risk of Parkinso... more The G2385R and R1628P LRRK2 gene variants have been associated with an increased risk of Parkinson's disease (PD) in the Asian population. Recently, a new LRRK2 gene variant, A419V, was reported to be a third risk variant for PD in Asian patients. Our objective was to investigate this finding in our cohort of Asian subjects. Eight hundred and twenty-eight subjects (404 PD patients, and 424 age and gender-matched control subjects without neurological disorders) were recruited. Genotyping was done by Taqman® allelic discrimination assay on an Applied Biosystems 7500 Fast Real-Time PCR machine. The heterozygous A419V genotype was found in only 1 patient with PD, compared to 3 in the control group (0.4% vs 1.3%), giving an odds ratio of 0.35 (95% confidence interval (CI), 0.01 to 3.79; P = 0.624). A419V is not an important LRRK2 risk variant in our Asian cohort of patients with PD. Our data are further supported by a literature review which showed that 4 out of 6 published studies r...
BioMed research international, 2014
The LRRK2 gene has been associated with both familial and sporadic forms of Parkinson's disea... more The LRRK2 gene has been associated with both familial and sporadic forms of Parkinson's disease (PD). The G2019S variant is commonly found in North African Arab and Caucasian PD patients, but this locus is monomorphic in Asians. The G2385R and R1628P variants are associated with a higher risk of developing PD in certain Asian populations but have not been studied in the Malaysian population. Therefore, we screened the G2385R and R1628P variants in 1,202 Malaysian subjects consisting of 695 cases and 507 controls. The G2385R and R1628P variants were associated with a 2.2-fold (P = 0.019) and 1.2-fold (P = 0.054) increased risk of PD, respectively. Our data concur with other reported findings in Chinese, Taiwanese, Singaporean, and Korean studies.
Handbook of Parkinson’s Disease, 2013
Journal of Neuroimmunology, 2014
Objective: Neuromyelitis optica (NMO) is an autoimmune, inflammatory disorder preferentially caus... more Objective: Neuromyelitis optica (NMO) is an autoimmune, inflammatory disorder preferentially causing optic neuritis (ON) and transverse myelitis (TM). We investigated the clinical features and disease course of aquaporin 4 antibody-positive (AQP4+) NMO/ NMO spectrum disorder (NMOSD) in an Asian population. Before AQP4 antibody discovery, many of these Asian patients were treated as multiple sclerosis or as Asian optico-spinal multiple sclerosis. Methods: All patients diagnosed to have AQP4+ NMO/NMOSD at Penang General Hospital, Penang, Malaysia were included. Case notes were reviewed to collect necessary data. Results: Thirteen patients were identified, and all (100%) were female, with 12 ethnic Chinese and 1 ethnic Malay. The median disease duration was 184 months (range: 2–405 months), with 77% had the disease for N10 years. Mean age at disease onset was 36 years (range: 18–84 years). Onset attacks were: ON (46%), TM (46%) and brainstem (8%). Eleven patients (85%) had relapsing course (10 NMO, 1 relapsing ON) while 2 (15%) had monophasic TM. Mean annualized relapse rate was 0.574, and median time to 1st relapse was 8 months (range: 3–45 months). The median time to NMO phenotype was 25 months (range: 3–63 months). After median disease duration of 184 months, 31% of patients had permanent bilateral visual disability (visual acuity b6/36 in the best eye), 46% had permanent motor disability (unable to walk N100 m unaided), 15% were wheelchair dependent, and 7% had died. Paroxysmal tonic spasm was present in 67% of patients with TM, while 82% of patients with ON eventually had bilateral eye involvement. Antinuclear antibody was positive in 31% of patients, and 2 patients had concomitant autoimmune disorders — one had systemic lupus erythematosus and the other had mixed connective tissue disease. The median time from disease onset to the diagnosis of AQP4 positivity was a long 154 months (range: 2– 402 months), as knowledge of AQP4 antibody was only made known in recent years and the AQP4 assay was only available to us recently. Conclusions: The clinical features and disease course of an AQP4+ NMO patient population in a multiethnic Asian country was described. Types of onset attacks and disabilities were comparable to the UK and Japanese series, apart from a worse visual disability in current study likely due to a longer follow up period. Ethnic Chinese seems overrepresented in our patient population. Genetic factors may play a role in the disease course.
Neurosurgery, 2013
BACKGROUND AND IMPORTANCE: Chorea acanthocytosis is a progressive hereditary neurodegenerative di... more BACKGROUND AND IMPORTANCE: Chorea acanthocytosis is a progressive hereditary neurodegenerative disorder characterized by hyperkinetic movements, seizures, and acanthocytosis in the absence of any lipid abnormality. Medical treatment is typically limited and disappointing. CLINICAL PRESENTATION: We report on a 32-year-old patient with chorea acanthocytosis with a failed attempt at awake deep brain stimulation (DBS) surgery due to intraoperative seizures and postoperative intracranial hematoma. He then underwent a second DBS operation, but under general anesthesia and with intraoperative magnetic resonance imaging guidance. Marked improvement in his dystonia, chorea, and overall quality of life was noted 2 and 8 months postoperatively. CONCLUSION: DBS surgery of the bilateral globus pallidus pars interna may be useful in controlling the hyperkinetic movements in neuroacanthocytosis. Because of the high propensity for seizures in this disorder, DBS performed under general anesthesia, w...
Acta Neurologica Belgica, 2013
The most common cause of suprasellar masses associated with hypopituitarism is pituitary adenoma ... more The most common cause of suprasellar masses associated with hypopituitarism is pituitary adenoma [1]. However, there are a variety of other causes of suprasellar masses, such as germ cell tumour (commonly involving the pineal gland), craniopharyngioma (usually in children), histiocytosis (usually presenting with diabetes insipidus), granulomatous lesions, leptomeningeal spread of tuberculosis (TB), metastases and brain lymphoma. We report a case of a woman with suprasellar mass, initially treated as TB of the central nervous system (CNS), with the diagnosis being revised to CNS lymphoma after a biopsy.
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Papers by Thien Thien Lim