Genome-wide association analysis identifies PLA2G4C as a susceptibility locus for Multiple System Atrophy

doi:10.21203/rs.3.rs-3461290/v1

Download PDF

Article

Genome-wide association analysis identifies PLA2G4C as a susceptibility locus for Multiple System Atrophy

https://doi.org/10.21203/rs.3.rs-3461290/v1

This work is licensed under a CC BY 4.0 License

Version 1

posted

You are reading this latest preprint version

To elucidate the molecular basis of multiple system atrophy (MSA), a neurodegenerative disease, we conducted a genome-wide association study (GWAS) in a Japanese MSA case/control series followed by replication studies in Japanese, Korean, Chinese, European, and North American samples. In the GWAS stage, rs2303744 on chromosome 19 showed a suggestive association (P = 6.5 × 10^− 7) that was replicated in additional Japanese samples (P = 2.9 × 10^− 6, odds ratio (OR) = 1.58; 95% confidence interval (CI), 1.30–1.91), and then confirmed as highly significant in a meta-analysis of East Asian population data (P = 5.0 × 10^− 15, OR = 1.49; 95% CI 1.35–1.65). The association of rs2303744 with MSA remained significant in combined European/North American samples (P = 0.017, OR = 1.12; 95% CI 1.02–1.23) despite allele frequencies being quite different between these populations. rs2303744 leads to an amino acid substitution in PLA2G4C that encodes the cPLA2γ lysophospholipase/transacylase. The cPLA2γ-Ile143 isoform encoded by the MSA risk allele has significantly decreased transacylase activity compared with the alternate cPLA2γ-Val143 isoform, and may perturb membrane phospholipids and promote oligodendroglial pathology.

Health sciences/Diseases/Neurological disorders/Neurodegenerative diseases/Parkinson's disease

Biological sciences/Genetics/Genetic association study/Genome-wide association studies

Multiple system atrophy (MSA) is a neurodegenerative disease characterized by autonomic failure with various combinations of parkinsonism and cerebellar ataxia ^1,2. The cardinal neuropathological hallmark of MSA is the presence of argyrophilic glial cytoplasmic inclusions (GCIs) in oligodendroglia, of which α–synuclein is a major component ^1,2. MSA is classified into two subtypes, MSA-C (characterized predominantly by cerebellar ataxia) and MSA-P (characterized predominantly by parkinsonism) ³. The relative frequencies of MSA-P compared to MSA-C in Europe and North America are reported as 63% and 60% of cases. In contrast, MSA-C in Japan is reported in 65–67% of cases ^4-8. Although MSA is largely considered to have no heritable component, several multiplex MSA families with confirmed neuropathological diagnoses have been reported ^9-11.

To elucidate the molecular basis of MSA, association studies focusing on candidate genes ^12-23 including SNCA ^19-21, LRRK2 ²³, and GBA ¹⁴ have been conducted. A genome-wide association study (GWAS) on 918 MSA patients of European ancestry and 3,864 controls revealed several potentially interesting gene loci ²⁴. Focusing on multiplex MSA families, we identified homozygous or compound heterozygous COQ2 mutations in two multi-incident MSA families and implicated functionally impaired COQ2 variants in sporadic MSA ²⁵. COQ2 p.Val393Ala is a common polymorphism in East Asian populations, and meta-analyses have demonstrated significant associations of COQ2 p.Val393Ala with sporadic MSA^26,27 . It should be noted that COQ2 p.Val393Ala was not informative in European and North American populations as it is monomorphic.

To further elucidate the molecular basis of MSA, we conducted a GWAS of MSA in Japanese samples. We replicated the genome-wide association in East Asian samples to directly identify a coding variant in a new susceptibility gene, PLA2G4C, that affects the transacylation activity of the enzyme encoded.

Association of rs2303744 located in exon 5 of PLA2G4C with MSA.

We conducted GWAS with a total of 382 cases and 385 controls originating from Japan (Table 1). Genome-wide significance was set at P < 1.1 × 10^− 7 using a stringent Bonferroni’s correction that considered the 456,818 informative SNPs examined. Quartile-quartile (QQ) plots of observed and expected P value distributions showed no systematic bias or unrecognized population structure (λ_GC, 0.995) (Supplementary Fig. 1). Figure 1A provides a Manhattan plot of the single-point association data for the genotypes obtained. Although no loci with genome-wide significance (P < 1.1 × 10^− 7) were observed, rs2303744 on chromosome 19 (GRCh38 NC_000019.10:g.48099691T > C (plus (+) strand) showed a suggestive association with P = 6.5 × 10^− 7 (Fig. 1). Note PLA2G4C is in the reverse orientation and rs2303744 in exon 5 denotes an amino acid substitution corresponding to Ile [ATC] > Val [GTC] at codon 143 (NM_003706). rs2303744 is the most highly associated SNP in the locus albeit with a block of neighboring SNPs spanning the adjacent gene, LIG1, upstream of the PLA2G4C promoter. LIG1 variants are in linkage disequilibrium and less associated given relatively high rates of population recombination within PLA2G4C, flanking rs2303744, that compromises its pairwise correlation with neighboring variants (Fig. 1B). Since the major allele of rs2303744 is G in East Asian populations, odds ratios were subsequently calculated based on the G allele as the reference.

We replicated the chromosome 19 (rs2303744) association in a second, independent Japanese series (P = 2.9 × 10^− 6, OR = 1.58; 95% CI 1.30–1.91), that combined gave a highly significant result, P = 2.1 × 10^− 11, OR = 1.61; 95% CI 1.40–1.85 (Table 2). The 38K JPN (Integrative Japanese Variation Database, Tohoku University Tohoku Medical Megabank Organization (ToMMo) (https://jmorp.megabank.tohoku.ac.jp/) control data provides yet more assurance (P = 2.2 × 10^− 16, OR = 1.62; 95% CI 1.46–1.80) (Supplementary Table 1).

Next, we sought to extend this observation beyond Japan to independent Korean, Chinese, European and North American samples. One caveat is that frequencies of the rs2303744 A allele in Japanese, Korean and Chinese controls are 0.394, 0.459 and 0.434, respectively, while those in European/North American, European, North American, or European (UCL) controls are 0.784, 0.781, 0.771, and 0.791, respectively.

Significant associations were observed in Korean (P = 2.6 × 10^− 4, OR = 1.38; 95% CI 1.16–1.63) and Chinese series (P = 0.031, OR = 1.33; 95% CI 1.03–1.72) (Table 2). Meta-analysis of East Asian populations combined (Japanese, Korean, and Chinese) sums the evidence for a highly significant association between rs2303744 and MSA (P = 5.0 × 10^− 15. OR = 1.49; 95% CI 1.35–1.65) (Fig. 2B). However, no association was observed between rs2303744 and MSA in any single European or North American series (Table 2). Nevertheless, meta-analysis of European/North American samples combined provided marginal support (P = 0.017, OR = 1.12; 95% CI 1.02–1.23) and meta-analysis of all the sample series remained highly significant (P = 0.0015, OR = 1.31; 95% CI 1.16–1.48) (Fig. 2).

Given these results we conducted multiple logistic regression analysis, adjusted for sex and population, to evaluate rs2303744 genotypic associations with MSA in East Asian samples (P = 6.6 × 10^− 16, OR = 1.51; 95% CI 1.37–1.67). Intriguingly, linear regression analysis adjusted for sex and population demonstrates a correlation between rs2303744 genotype and age at onset of MSA, with AA genotypes showing the youngest mean ages at onset in the Japanese, Korean and Chinese samples (P = 0.0010) (Fig. 3). Meta-analysis including Japanese, Korean and Chinese populations, using a recessive model demonstrated the most evidence for association between the AA genotype and MSA (P = 1.8 × 10^− 12, OR = 1.86; 95% CI 1.57–2.21). When patients with MSA were subdivided into MSA-C and MSA-P subtypes, multiple regression analysis adjusted for sex and population showed significant associations in MSA-C (P = 8.6 × 10^− 14, OR = 1.57; 95% CI 1.39–1.77) and MSA-P (P = 7.2 × 10^− 6, OR = 1.38; 95% CI 1.20–1.59) in East Asian populations (Supplementary Table 2).

Functional evaluation of PLA2G4C with rs2303744

Functional analysis of transiently expressed cPLA2γ, the gene product of PLA2G4C, was conducted to examine the effect of the rs2303744 SNP [PLA2G4C c.427A > G (cPLA2γ p.Ile143Val) (NM_001159323.1; NP_001152795.1)]. Recombinant proteins for alternate alleles were transiently expressed in HEK293 cells and lysophospholipase/transacylation activities were examined. Western blotting revealed the expression of each allele was not significantly altered (Fig. 4A). When the substrate [¹⁴C]lysophosphatidylcholine (LPC, 1-[¹⁴C]oleoyl-glycerophosphocholine (GPC)) was incubated with protein extract from FLAG-cPLA2γ-transfected HEK293 cells, both [¹⁴C]FFA ([¹⁴C]oleic acid) and [¹⁴C]PC(1,2-diacyl-GPC) reaction products were observed (Fig. 4B, C). In contrast, no reaction products were observed using mock (empty pcDNA4/TO vector)-transfected cell lysate. Recombinant FLAG-cPLA2γ catalyzes lysophospholipase activity but as shown by the release of [¹⁴C]FFA from [¹⁴C]LPC, the recombinant enzyme also catalyzes the transacylation reaction of [¹⁴C]FFA from [¹⁴C]LPC to another [¹⁴C]LPC to form [¹⁴C]PC (Fig. 4B, E).

Next, the activities of alternate alleles, cPLA2γ-Ile143 and cPLA2γ-Val143, were compared. Although the lysophospholipase activities for both enzymes were similar, the transacylation activity of cPLA2γ-143Val was significantly higher than that of cPLA2γ-Ile143 (P = 0.038) (Fig. 4B, C). We conclude the cPLA2γ p.Ile143Val amino acid substitution alters the transacylation activity of cPLA2γ.

The three-dimensional (3D) structural relationship between Ile143 and the active Ser82 residue of cPLA2γ was previously predicted by SWISS-Model based on the 3D-structure of cPLA2α and cPLA2δ, extrapolated from X-ray crystallography data^28,29. Using the revised AlphaFold program³⁰, five 3D-structures of cPLA2γ were predicted. In silico docking experiments were carried out between the modeled 3D-structure of cPLA2γ and LPC (1-acyl-sn-glycero-3-phosphocholine) using Autodock Vina³¹. Energy minimization and molecular dynamics (MD) calculations were continued using the docking model with the highest AutoDock score including calculations of heating and equilibration. Among the five 3D-structures, one structure was selected showing the highest score with the in silico binding of LPC (Fig. 4D).

In silico docking experiments between the 3D-structure of cPLA2γ and LPC predicted that Ile143 (Val143) is located in a surface hydrophobic cavity in the catalytic pocket including the catalytic Ser82. The distance between HO- of Ser82 and two CH₃- of Ile143 was calculated as approximately 7.9 and 8.1 Å, respectively (Fig. 4D). The catalytic Ser82 is shown to be close to the phosphate moiety of LPC with the distance calculated as 3.5 Å (Fig. 4D lower), but distant from the sn-1 ester bond of LPC to react with hydrolysis or transacylation, suggesting that Ser82 and the sn-1 ester bond needs to get closer after binding of LPC. Increasing the space by the substitution from Ile to Val in a methyl unit may facilitate the movement of sn-1 ester bond to react with Ser82 and result in the augmented transacylation activity.

Genome-wide association analysis of MSA in the Japanese population and subsequent meta-analysis in Japanese, Korean, and Chinese patients demonstrates that rs2303744 G > A is significantly associated with MSA (P = 5.0 × 10^− 15, Fig. 2B, Table 2). In East Asia, the rs2303744 ‘A’ risk allele is marginally more prominent in the cerebellar subtype (MSA-C) (P = 8.6 × 10^− 14, OR = 1.57; 95% CI 1.39–1.77) than in the parkinsonism subtype (MSA-P) (P = 7.2 × 10^− 6, OR = 1.38; 95% CI 1.20–1.59), and the AA genotype is associated with younger onset disease (P = 0.001).

While an association between rs2303744 and MSA was observed in North American and European populations, it was considerably less significant than in the Japanese population and East Asia. In part, the difference may reflect the frequencies of the rs2303744 ‘A’ risk allele which is 0.39–0.46 in East Asia (Japan, Korea, and China) compared to 0.77–0.79 in European/North American populations (Table 2; Supplementary Fig. 2). However, the magnitude of association may also reflect population differences in rs2303744 tagged haplotype composition and linkage disequilibrium. The high frequency of the rs2303744 ‘A’ risk allele and modest effect size, most especially in MSA in North American and European populations, raises a possibility that variability in cis may contribute to or underlie the association. Moreover, other genetic factors or environmental factors most likely contribute to population-specific differences in the association of rs2303744 with MSA. Further analysis of rs2303744 ‘A’ risk alleles and associated haplotypes including long-read sequencing is warranted in MSA cases in both populations.

The rs2303744 SNP, located in exon 5 of PLA2G4C c.427G > A, encodes p.Val143Ile allelic isoforms of cytosolic phospholipase A2 gamma (cPLA2γ). cPLA2γ was originally identified as a phospholipase A2 (PLA2) belonging to the PLA2G4 family ³². It is predominantly expressed in the brain, heart and skeletal muscle ^33,34 and appears to be involved in remodeling and clearance of membrane phospholipids ^35–37. In brain, single cell RNA sequencing reveals enhanced expression in rod photoreceptor cells and oligodendrocytes³⁸. cPLA2γ has two enzyme activities catalyzing both lysophospholipase and transacylation reactions. Curiously, while lysophospholipase activity is equivalent for cPLA2γ Val143 and Ile143 isoforms, we demonstrate cPLA2γ Ile143 has decreased transacylation activity (Fig. 4B, C, E). The physiologic consequence, if any, is unclear. However, activation of PLA2 enzymes, including cPLA2 (PLA2G4A) and iPLA2 (PLA2G6A), will lead to lysophospholipid accumulation if those products are not reacylated to parent phospholipids through acyl-CoA acyltransferases³⁹. High levels of 1-O-alkyl or 1-O-alkenyl phospholipids are present in brain³⁸, and 1-O-alkyl or 1-O-alkenyl lysophospholipids are formed primarily by the activation of PLA2. However, acyl-CoA acyltransferase activity for 1-O-alkyl or 1-O-alkenyl lysophospholipids is lower than that for 1-acyl lysophospholipids ³⁹. In addition, 1-O-alkyl or 1-O-alkenyl lysophospholipids are resistant to degradation by lysophospholipase activity. The transacylation activity of cPLA2γ is able to remodel the ether-linked lysophospholipids to phospholipids through the transfer of fatty acid of sn-1 position of 1-O-acyl lysophospholipids to ether-linked lysophospholipids (Fig. 4E). Hence, the higher clearance of sn-1 ether-linked lysophospholipids by cPLA2γ-Val143 over cPLA2γ-Ile143 may also play a protective role against neurodegeneration.

Intriguingly, the physiologic and pathologic roles of α-synuclein have been shown to be intimately related to lipid composition and trafficking ^40–43. Of interest, recessively-inherited mutations in iPLA2 (PLA2G6) cause infantile neuroaxonal dystrophy (neurodegeneration with brain iron accumulation-2A) with clinical presentations of dystonia/parkinsonism and cerebellar ataxia ⁴⁴. Pathologic features include prominent Lewy bodies/neurites (albeit without notable GCIs), neurofibrillary tangles/threads and axonal spheroids, often associated with iron deposition in the globus pallidus and substantia nigra ⁴⁵. iPLA2 (PLA2G6) is also involved in remodeling phospholipids through the release of sn-2 fatty acid and 1-radyl lysophospholipid. Although no pathology or α-synuclein biology in the context of cPLA2γ has been examined, the present study suggests altered cPLA2γ expression and/or transacylase activity may underlie remodeling of membrane phospholipids, and enhance α-synuclein aggregation in oligodendroglia. Further genomic and functional studies are necessary to elaborate the role of cPLA2γ in neurons versus oligodendroglia, its effect on α-synuclein biology, and the pathobiologic mechanism of this devastating neurodegenerative disease.

Acknowledgments

We deeply thank the patients for participating in the study. We acknowledge Drs. Takahisa Kawaguchi and Tatsuhiko Tsunoda at RIKEN Center for Integrative Medical Sciences, Yokohama, Japan, for their kind advices for the genome-wide association study including the PCA analysis. We also acknowledge Prof. Yukinori Okada for his valuable advice on the effect of regional differences in the genome variations on the results of GWAS. This work was supported in part by KAKENHI (Grants-in-Aid for Scientific Research on Innovative Areas Nos. 22129001 and 22129002) from the Ministry of Education, Culture, Sports, Science and Technology of Japan, Grants-in-Aid [H23-Jitsuyoka (Nanbyo)-Ippan-004 and H26-Jitsuyoka (Nanbyo)-Ippan-080] from the Ministry of Health, Welfare and Labour, Japan, and grants (Nos. 15ek0108065h0002, 16kk0205001h0001, 17kk0205001h0002, and 17ek0109279h0001) from the Japan Agency for Medical Research and Development (AMED) to S.T. This work was in part supported under the framework of international cooperation program managed by National Research Foundation of Korea (Grant Number: NRF-2015K2A1A2070274) to B. J. Korean DNA samples for this study were provided by the Seoul National University Hospital Human Biobank, a member of the National Biobank of Korea, which is supported by the Ministry of Health and Welfare. All samples derived from the National Biobank of Korea were obtained with informed consent under institutional review board-approved protocols and we thank Erika Scott⁵ for technical assistance. MJF gratefully acknowledges support from the Lee & Lauren Fixel Chair for Parkinson’s disease research. VC received grants from the Multiple System Atrophy Trust (PROSPECT-M-UK), Multiple System Atrophy Coalition Grant 567540, The Guarantors of Brain Grant 565908, King Baudouin Foundation/ Sophia Fund. VC received grants from the Multiple System Atrophy Trust (PROSPECT-M-UK), Multiple System Atrophy Coalition Grant 567540, The Guarantors of Brain Grant 565908, King Baudouin Foundation/ Sophia Fund.

Wakabayashi, K., Yoshimoto, M., Tsuji, S. & Takahashi, H. Alpha-synuclein immunoreactivity in glial cytoplasmic inclusions in multiple system atrophy. Neurosci Lett 249, 180-2 (1998).
Tu, P.H. et al. Glial cytoplasmic inclusions in white matter oligodendrocytes of multiple system atrophy brains contain insoluble alpha-synuclein. Ann Neurol 44, 415-22 (1998).
Gilman, S. et al. Second consensus statement on the diagnosis of multiple system atrophy. Neurology 71, 670-6 (2008).
Watanabe, H. et al. Progression and prognosis in multiple system atrophy: an analysis of 230 Japanese patients. Brain 125, 1070-83 (2002).
Tsuji, S., Onodera, O., Goto, J., Nishizawa, M. & Study Group on Ataxic, D. Sporadic ataxias in Japan--a population-based epidemiological study. Cerebellum 7, 189-97 (2008).
Geser, F. et al. The European Multiple System Atrophy-Study Group (EMSA-SG). J Neural Transm (Vienna) 112, 1677-86 (2005).
Ozawa, T. et al. Difference in MSA phenotype distribution between populations: genetics or environment? J Parkinsons Dis 2, 7-18 (2012).
Yabe, I. et al. MSA-C is the predominant clinical phenotype of MSA in Japan: analysis of 142 patients with probable MSA. J Neurol Sci 249, 115-21 (2006).
Hara, K. et al. Multiplex families with multiple system atrophy. Arch Neurol 64, 545-51 (2007).
Wullner, U., Schmitt, I., Kammal, M., Kretzschmar, H.A. & Neumann, M. Definite multiple system atrophy in a German family. J Neurol Neurosurg Psychiatry 80, 449-50 (2009).
Itoh, K. et al. Definite familial multiple system atrophy with unknown genetics. Neuropathology 34, 309-13 (2014).
Nishimura, M. et al. Contribution of the interleukin-1beta gene polymorphism in multiple system atrophy. Mov Disord 17, 808-11 (2002).
Combarros, O., Infante, J., Llorca, J. & Berciano, J. Interleukin-1A (-889) genetic polymorphism increases the risk of multiple system atrophy. Mov Disord 18, 1385-6 (2003).
Mitsui, J. et al. Variants associated with Gaucher disease in multiple system atrophy. Ann Clin Transl Neurol 2, 417-26 (2015).
Soma, H. et al. Associations between multiple system atrophy and polymorphisms of SLC1A4, SQSTM1, and EIF4EBP1 genes. Mov Disord 23, 1161-7 (2008).
Infante, J., Llorca, J., Berciano, J. & Combarros, O. Interleukin-8, intercellular adhesion molecule-1 and tumour necrosis factor-alpha gene polymorphisms and the risk for multiple system atrophy. J Neurol Sci 228, 11-3 (2005).
Furiya, Y. et al. Alpha-1-antichymotrypsin gene polymorphism and susceptibility to multiple system atrophy (MSA). Brain Res Mol Brain Res 138, 178-81 (2005).
Nishimura, M., Kuno, S., Kaji, R. & Kawakami, H. Influence of a tumor necrosis factor gene polymorphism in Japanese patients with multiple system atrophy. Neurosci Lett 374, 218-21 (2005).
Scholz, S.W. et al. SNCA variants are associated with increased risk for multiple system atrophy. Ann Neurol 65, 610-4 (2009).
Al-Chalabi, A. et al. Genetic variants of the alpha-synuclein gene SNCA are associated with multiple system atrophy. PLoS One 4, e7114 (2009).
Yun, J.Y. et al. SNCA variants and multiple system atrophy. Ann Neurol 67, 554-5 (2010).
Guo, X.Y. et al. An association analysis of the rs1572931 polymorphism of the RAB7L1 gene in Parkinson's disease, amyotrophic lateral sclerosis and multiple system atrophy in China. Eur J Neurol 21, 1337-43 (2014).
Heckman, M.G. et al. LRRK2 exonic variants and risk of multiple system atrophy. Neurology 83, 2256-61 (2014).
Sailer, A. et al. A genome-wide association study in multiple system atrophy. Neurology 87, 1591-1598 (2016).
Collaboration, M.S.A.R. Mutations in COQ2 in familial and sporadic multiple-system atrophy. N Engl J Med 369, 233-44 (2013).
Porto, K.J. et al. COQ2 V393A confers high risk susceptibility for multiple system atrophy in East Asian population. J Neurol Sci 429, 117623 (2021).
Zhao, Q. et al. Association of the COQ2 V393A variant with risk of multiple system atrophy in East Asians: a case-control study and meta-analysis of the literature. Neurol Sci 37, 423-30 (2016).
Dessen, A. et al. Crystal structure of human cytosolic phospholipase A2 reveals a novel topology and catalytic mechanism. Cell 97, 349-60 (1999).
Wang, H. et al. Structure of Human GIVD Cytosolic Phospholipase A2 Reveals Insights into Substrate Recognition. J Mol Biol 428, 2769-79 (2016).
Mirdita, M. et al. ColabFold: making protein folding accessible to all. Nat Methods 19, 679-682 (2022).
Eberhardt, J., Santos-Martins, D., Tillack, A.F. & Forli, S. AutoDock Vina 1.2.0: New Docking Methods, Expanded Force Field, and Python Bindings. J Chem Inf Model 61, 3891-3898 (2021).
Asai, K. et al. Human group IVC phospholipase A2 (cPLA2gamma). Roles in the membrane remodeling and activation induced by oxidative stress. J Biol Chem 278, 8809-14 (2003).
Pickard, R.T., Strifler, B.A., Kramer, R.M. & Sharp, J.D. Molecular cloning of two new human paralogs of 85-kDa cytosolic phospholipase A2. J Biol Chem 274, 8823-31 (1999).
Underwood, K.W. et al. A novel calcium-independent phospholipase A2, cPLA2-gamma, that is prenylated and contains homology to cPLA2. J Biol Chem 273, 21926-32 (1998).
Stewart, A., Ghosh, M., Spencer, D.M. & Leslie, C.C. Enzymatic properties of human cytosolic phospholipase A(2)gamma. J Biol Chem 277, 29526-36 (2002).
Jenkins, C.M. et al. Purification of recombinant human cPLA2 gamma and identification of C-terminal farnesylation, proteolytic processing, and carboxymethylation by MALDI-TOF-TOF analysis. Biochemistry 42, 11798-807 (2003).
Yamashita, A. et al. Roles of C-terminal processing, and involvement in transacylation reaction of human group IVC phospholipase A2 (cPLA2gamma). J Biochem 137, 557-67 (2005).
Karlsson, M. et al. A single-cell type transcriptomics map of human tissues. Sci Adv 7(2021).
Yamashita, A. et al. Acyltransferases and transacylases that determine the fatty acid composition of glycerolipids and the metabolism of bioactive lipid mediators in mammalian cells and model organisms. Prog Lipid Res 53, 18-81 (2014).
Jiang, Z., de Messieres, M. & Lee, J.C. Membrane remodeling by alpha-synuclein and effects on amyloid formation. J Am Chem Soc 135, 15970-3 (2013).
Sharon, R. et al. The formation of highly soluble oligomers of alpha-synuclein is regulated by fatty acids and enhanced in Parkinson's disease. Neuron 37, 583-95 (2003).
Ruiperez, V., Darios, F. & Davletov, B. Alpha-synuclein, lipids and Parkinson's disease. Prog Lipid Res 49, 420-8 (2010).
Westphal, C.H. & Chandra, S.S. Monomeric synucleins generate membrane curvature. J Biol Chem 288, 1829-40 (2013).
Salih, M.A. et al. New findings in a global approach to dissect the whole phenotype of PLA2G6 gene mutations. PLoS One 8, e76831 (2013).
Paisan-Ruiz, C. et al. Widespread Lewy body and tau accumulation in childhood and adult onset dystonia-parkinsonism cases with PLA2G6 mutations. Neurobiol Aging 33, 814-23 (2012).

Table 1. Demographic data of MSA cases and controls

GWAS stage

	Genotyping	Populations	Number	Age at sampling	Age at onset	Male/Female	Phenotype (MSA-C/ MSA-P/ Unclassified)
MSA patients	HumanHap 550K/Human660W-Quad	Japanese	382	62.4 (8.1)	59.0 (8.2)	211/171	271/92/19
Control Subjects	HumanHap 550K/Human660W-Quad	Japanese	385	65.6 (16.2)	N.A.	198/187	N.A.

Replication stage

	Genotyping	Populations	Number	Age at sampling	Age at onset	Male/Female	Phenotype (MSA-C/ MSA-P/ Unclassified)
MSA patients	Exome	Japanese	373	63.4 (8.9)	59.6, 8.8	182/191	275/89/9
	TaqMan SNP Genotyping	Korean	642	N.A.	59.6, 8.9	316/326	218/276/148
	Sanger	Chinese	202	58.3(9.1)	54.8(8.0)	124/78	121/51/30
	Illumina genotyping BeadChips	European/North American	918	N.A.	N.A.	724/194	104/213/601
	Human660W-Quad	European	154	59.0, 7.9	56.6, 8.6	94/60	134/12/8
	Exome	North American	169	N.D.	58.4, 9.6	101/68	52/105/12
	Illumina NeuroBooster array	European (UCL)	1015	66, 8.49	58.5, 9.3	522/493	217/262/536
Control Subjects	Exome	Japanese	495	55.3 (15.6)	N.A.	198/297	N.A.
	TaqMan SNP Genotyping	Korean	446	N.A.	N.A.	187/259	N.A.
	Sanger	Chinese	274	59.1(7.8)	N.A.	151/123	N.A.
	Illumina genotyping BeadChips	European/North American	3884	N.A.	N.A.	3066/818	N.A.
	Human660W-Quad	European	162	62.0, 9.0	N.A.	82/80	N.A.
	Exome	North American	290	65.2 (9.0)	N.A.	153/137	N.A.
	Illumina NeuroBooster array	European (UCL)	4894	N.A.	N.A.	2747/2098	N.A.

Table 2. Allelic association test of rs2303744 (PLA2G4C) for multiple system atrophy (MSA) in Japanese, Chinese, Korean, European and North American series

dbSNP rs ID	Gene	Risk Allele	Allele	Stage	Case		Control		OR	P value
dbSNP rs ID	Gene	Risk Allele	Allele	Stage	A	G	A	G	OR	P value
rs2303744	PLA2G4C	A	A/G	GWAS^#	380 (0.497)	384 (0.503)	286 (0.371)	484 (0.629)	1.67 (1.37–2.05)	6.5×10^− 7
				Replication^#	391 (0.524)	355 (0.476)	407 (0.411)	583 (0.589)	1.58 (1.30–1.91)	2.9×10^− 6
				Combined^#	771 (0.511)	739 (0.489)	693 (0.394)	1067 (0.606)	1.61 (1.40–1.85)	2.1×10^− 11
				Korean	691 (0.538)	593 (0.462)	409 (0.459)	483 (0.541)	1.38 (1.16–1.63)	2.6×10^− 4
				Chinese	204 (0.500)	200 (0.500)	238 (0.434)	310 (0.566)	1.33 (1.03–1.72)	0.031
				European/North American*	1469 (0.804)	357 (0.196)	6087 (0.784)	1673 (0.216)	1.13 (1.00–1.28)	0.059
				European	250 (0.812)	58 (0.188)	253 (0.781)	71 (0.219)	1.21 (0.82–1.78)	0.34
				North American	269 (0.796)	69 (0.204)	447 (0.771)	133 (0.229)	1.16 (0.84–1.61)	0.37
				European (UCL)	1640 (0.808)	300 (0.192)	7744 (0.791)	2044 (0.209)	1.08 (0.91–1.29)	0.10

^#Japan

* Five MSA and four control samples were excluded based on the quality control (Sailer, A. et al. A genome-wide association study in multiple system atrophy. Neurology 87, 1591-1598 (2016)).

There is NO Competing Interest.

Supplementaryver20.pdf
Supplementary Fig.1, Supplementary Fig. 2, Supplementary Table 1 and Supplementary Table 2

Download PDF

Version 1

posted

You are reading this latest preprint version

Genome-wide association analysis identifies PLA2G4C as a susceptibility locus for Multiple System Atrophy

Status:

Version 1

Abstract

Figures

Introduction

RESULTS

DISCUSSION

Declarations

Acknowledgments

References

Tables

Additional Declarations

Supplementary Files

Status:

Version 1