Publications (9) View all
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Article: Widespread Lewy body and tau accumulation in childhood and adult onset dystonia-parkinsonism cases with PLA2G6 mutations.
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ABSTRACT: The 2 major types of neurodegeneration with brain iron accumulation (NBIA) are the pantothenate kinase type 2 (PANK2)-associated neurodegeneration (PKAN) and NBIA2 or infantile neuroaxonal dystrophy (INAD) due to mutations in the phospholipase A2, group VI (PLA2G6) gene. We have recently demonstrated clinical heterogeneity in patients with mutations in the PLA2G6 gene by identifying a poorly defined subgroup of patients who present late with dystonia and parkinsonism. We report the clinical and genetic features of 7 cases with PLA2G6 mutations. Brain was available in 5 cases with an age of death ranging from 8 to 36 years and showed widespread alpha-synuclein-positive Lewy pathology, which was particularly severe in the neocortex, indicating that the Lewy pathology spread corresponded to Braak stage 6 and was that of the "diffuse neocortical type". In 3 cases there was hyperphosphorylated tau accumulation in both cellular processes as threads and neuronal perikarya as pretangles and neurofibrillary tangles. Later onset cases tended to have less tau involvement but still severe alpha-synuclein pathology. The clinical and neuropathological features clearly represent a link between PLA2G6 and parkinsonian disorders.Neurobiology of aging 04/2012; 33(4):814-23. · 5.94 Impact Factor -
Article: Pantothenate kinase-associated neurodegeneration is not a synucleinopathy.
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ABSTRACT: Aims: Mutations in the pantothenate kinase 2 gene (PANK2) are responsible for the most common type of neurodegeneration with brain iron accumulation (NBIA), known as pantothenate kinase-associated neurodegeneration (PKAN). Historically, NBIA is considered a synucleinopathy with numerous reports of NBIA cases with Lewy bodies and Lewy neurites and some cases reporting additional abnormal tau accumulation. However, clinicopathological correlations in genetically proven PKAN cases are rare. We describe the clinical, genetic and neuropathological features of three unrelated PKAN cases. Methods: All three cases were genetically screened for the PANK2 gene mutations using standard Sanger PCR sequencing. A detailed neuropathological assessment of the three cases was performed using histochemical and immunohistochemical preparations. Results: All cases had classical axonal swellings and Perl's positive iron deposition in the basal ganglia. In contrast to neuroaxonal dystrophies due to mutation of the phospholipase A2, group VI (PLA2G6) gene, in which Lewy body (LB) pathology is widespread, no α-synuclein accumulation was detected in any of our PKAN cases. In one case (20-year-old male) there was significant tau pathology comprising neurofibrillary tangles and neuropil threads, with very subtle tau pathology in another case. Conclusions: These findings indicate that PKAN is not a synucleinopathy and, hence the cellular pathways implicated in this disease are unlikely to be relevant for the pathomechanism of Lewy body disorders. © 2012 The Authors. Neuropathology and Applied Neurobiology © 2012 British Neuropathological Society.Neuropathology and Applied Neurobiology 03/2012; · 3.80 Impact Factor -
Article: Mutational analysis of parkin and PINK1 in multiple system atrophy.
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ABSTRACT: Multiple system atrophy (MSA) and Parkinson's disease (PD) are progressive neurodegenerative disorders with overlapping clinical, biochemical and genetic features. To test the hypothesis that the PD genes parkin and PINK1 also play a role in the pathogenesis of MSA, we performed a mutational screening study involving 87 pathologically proven MSA cases. In parkin we identified eight sequence variants and four heterozygous deletions and in PINK1 we identified nine variants of which two silent mutations have not been previously reported (p.Gly189Gly and p.Arg337Arg). The frequencies of the observed variants were not significantly different from previously published control data and none of the possibly pathogenic variants were found in a homozygous state. Our results indicate that genetic variants at the parkin and PINK1 loci do not play a critical role in the pathogenesis of MSA.Neurobiology of aging 03/2011; 32(3):548.e5-7. · 5.94 Impact Factor -
Article: An ITPR1 gene deletion causes spinocerebellar ataxia 15/16: a genetic, clinical and radiological description.
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ABSTRACT: The purpose of this study was to characterise a novel family with very slowly progressive pure spinocerebellar ataxia (SCA) caused by a deletion in the inositol 1,4,5-triphosphate receptor 1 (ITPR1) gene on chromosome 3. This is a detailed clinical, genetic, and radiological description of the genotype. Deletions in ITPR1 have been shown to cause SCA15/SCA16 in six families to date. A further Japanese family has been identified with an ITPR1 point mutation. The exact prevalence is as yet unknown, but is probably higher than previously thought. The clinical phenotype of the family is described, and videotaped clinical examinations are presented. Serial brain magnetic resonance imaging studies were carried out on one affected individual, and genetic analysis was performed on several family members. Protein analysis confirmed the ITPR1 deletion. Affected subjects display a remarkably slow, almost pure cerebellar syndrome. Serial magnetic resonance imaging shows moderate cerebellar atrophy with mild inferior parietal and temporal cortical volume loss. Genetic analysis shows a deletion of 346,487 bp in ITPR1 (the second largest ITPR1 deletion reported to date), suggesting SCA15 is due to a loss of ITPR1 function. Western blotting of lymphoblastoid cell line protein confirms reduced ITPR1 protein levels. SCA15 is a slowly or nonprogressive pure cerebellar ataxia, which appears to be caused by a loss of ITPR1 function and a reduction in the translated protein. Patients with nonprogressive or slowly progressive ataxia should be screened for ITPR1 defects.Movement Disorders 10/2010; 25(13):2176-82. · 4.51 Impact Factor -
Article: A Huntington's disease phenocopy characterized by pallido-nigro-luysian degeneration with brain iron accumulation and p62-positive glial inclusions.
Neuropathology and Applied Neurobiology 05/2010; 36(6):551-7. · 3.80 Impact Factor
