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3.071 ATYPICAL HEREDITARY HYPEREKPLEXIA CAUSED BY HETEROZYGOUS DELETION MUTATION IN THE GLRA1 EXON-1
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Wednesday, 14 December 2011 / Parkinsonism and Related Disorders 18S2 (2012) S161–S234
an important copper-transporting P-type ATP-ase. Its dysfunction leads to copper accumulation in the liver and extrahepatic organs such as brain and cornea. Objective: To report a patient with compound heterozygotic ATP7B mutations, already described in WD, but with no clinical manifestation of the disease. Case report: The authors report an adult patient with a longterm history of psychiatric disorders in whom a compound heterozygotic ATP7B mutation, already described in Wilson’s disease (WD) (p.Met645Arg (C1934t>G)/ c.51+4A→T), was found. Hypoceruloplasminemia and hypocupremia were detected but no overt clinical manifestations (hepatic and central nervous system) of WD were present. Conclusion: It is conceivable that some patients might carry a combination of heterozygous mutations, where each mutation encodes distinct parts of exonic and/or intronic zones of ATP7B gene that may eventually lead to a more or less severe functional impairment of copper metabolism and even to no overt clinical hepatic and/or central nervous system manifestations as observed in our patient. 3.068 MOLECULAR GENETIC STUDIES ON INDIAN WILSON’S DISEASE PATIENTS K. Ray1 , S. Mukherjee1 , S. Dutta1 , M. Sengupta1 , P.K. Gangopadhyay2 , A. Bavdekar3 , S.K. Das4 . 1 Molecular & Human Genetics, CSIR-Indian Institute of Chemical Biology, 2 Calcutta National Medical College, Kolkata, 3 King Edward Memorial Hospital, Pune, 4 Bangur Institute of Neurosciences, Kolkata, India Introduction: Wilson’s disease (WD) is an autosomal recessive disorder caused by defects in the ATP7B resulting in accumulation of copper in liver and brain and have overlapping clinical features with other neurological disesaes including Parkinson’s Disease (PD). Identification of mutations in the ATP7B gene is the best way to diagnose WD. Objectives: We aim to identify the molecular bases of WD in Indian patients, attempt to correlate ATP7B genotype with the WD phenotype, examine role of modifier genes and translate the study for the benefit of patients by unequivocal diagnosis of the disease. Materials and Methods: Mostly neurological patients from 177 unrelated Indian families and their first-degree relatives comprising 658 individuals were enrolled in this study. Microsatellite and SNP markers linked to ATP7B were used to build haplotypes and PCRsequencing based approach was taken to identify genetic variants. Results: Both mutations were detected in 102 and single mutation in 57 unrelated WD patients. A total of 8 common (70% of characterized defects) and 52 private mutations were detected. Interestingly, homozygotes for different mutations that would be expected to produce similar disease outcome showed phenotypic heterogeneity including severity of the disease. Conclusions: The common mutations identified in Indian WD patients would aid in detection of carriers and presymptomatic cases with much higher efficiency. Dissection of phenotypic heterogeneity under similar mutation background would let us explore roles of modifier loci. The study is supported by Council of Scientific and Industrial Research (CSIR) Government of India 3.069 EXOME SEQUENCING IDENTIFIES NOVEL SACSIN GENE MUTATIONS IN A CHINESE FAMILY L. Shen1 , Z. Zhan1 , X. Liao1 , Z. Hu1 , J. Wang2 , J. Du1 , B. Tang1 . 1 Department of Neurology, 2 Xiangya Hospital, Central South University, Changsha, China Object: To investigate the disease-causing mutations of a autosomal recessive spastic paraplegia families. Patients and Methods: The two generations non-consanguineous family containing five family members (the proband and her
brother are patients, but her sister and parents are nomal) were rectuited. The probrand, a 39 woman and her brother, a 36 man, suffering from gait disorder, dysarthria, and decreased vision since their early childhood were clinically diagnosed as autosomal recessive spastic paraplegia. Genomic DNA was prepared from venous blood by standard procedures. Direct sequencing had been performed on the proband and mutations of SPG11, SP15, SPG5, SPG7, SPG1, SPG2 had been ruled out. Exome sequencing was carried out on the genomic DNA of the proband and her brother. Bioinformatics analysis, cosegregated analysis and normal matched control analysis were done on the result of exome sequencing to identified the disease-causing mutation. Result: Peripheral lesion and cerebellar atrophy were showed on the proband by electromyologram and MRI scaing, respectively. Exome sequencing confirmed that two patients both had sacsin gene compound heterozygous mutations: c.5840G>G/C, p.P1947R and c.410delT, p.L410XfsX411. These novel variants were at a highly conserved position, were predicted to be damaging, completely cosegregated with the phenotype, and were absent among the 200 geographical matched controls. Conclusion: We identified the first Charlevoix-Saguenay-Spastic Ataxia family in Chinese population and expanded the sacsin gene mutation spectrum. The exome sequencing may be a effective tool for genetic diagnosis of rare autosomal recessive diease. This work was supported the National Natural Science Foundation of China: 30671151, 30971034 3.070 AUTOSOMAL DOMINANT CORTICAL MYOCLONUS AND EPILEPSY (ADCME) – NEW MUTATION IN POLISH FAMILY? S. Budrewicz1 , M. Koszewicz1 , E. Koziorowska-Gawron1 , K. Slotwinski1 , R. Podemski1 , P. Striano2 . 1 Neurology, Wroclaw Medical University, Wroclaw, Poland; 2 Muscular and Neurodegenerative Diseases Unit, University of Genoa, Genoa, Italy ADCME is a disorder of homogenous clinical phenotype, described all over the word, inherited autosomal dominant with high gene penetration, and heterogenic genotypes. In the course of ADCME positional and action tremor, prevailing in upper limbs and sporadic, generalized seizures are observed. The disorder has an unprogressive course. In Polish family, in 3 generations positional and action tremor as well as myoclonus in upper limbs, less pronounced in trunk and lower limbs were observed. Tremor and myoclonus occurred under the age of 20 and were exaggerated by emotions, touch and physical exercises (9 persons presented action and positional tremor, 3 of them had sporadic, epileptic seizures which appeared in older age – the forth decade of life). EMG revealed positional and action tremor with frequency of 7–8 Hz in upper limbs. Generalized slow waves, spike discharges and positive reaction for photostimulation were registered in EEG. In visual evoked potentials (VEP) high amplitude of potential P100 was recorded. There were no positive effect during therapy with beta-blockers or after alcoholic drinks. In genetic studies, in cooperation with the University in Genoa, linkage to chromosome 8, 2, and 5 was excluded. Clinical and electrophysiological data found in Polish family may fulfill criteria of ADCME. We are searching for the new mutation. 3.071 ATYPICAL HEREDITARY HYPEREKPLEXIA CAUSED BY HETEROZYGOUS DELETION MUTATION IN THE GLRA1 EXON-1 W.T. Yoon1 , W.Y. Lee2 , C.-S. Ki3 , J.W. Cho2 . 1 Neurology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, 2 Neurology, 3 Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea Background: Hyperekplexia, also known as startle disease is a rare non-epileptic, neurological disorder characterized by infantile generalized muscular stiffness and excessive startle responses
Wednesday, 14 December 2011 / Parkinsonism and Related Disorders 18S2 (2012) S161–S234
to unexpected acoustic or tactile stimuli. Genetic studies have linked mutations in the gene encoding the alpha-1 subunit of the inhibitory glycine receptor (GLRA1) with hereditary hyperekplexia. Cases: A 23-year-old man presented to us with gait disturbance and the stiffness of both legs seven months ago. He was previously diagnosed as myoclonic epilepsy, taking antiepileptic drugs for 20 years. His older sister, a 34-year-old woman had the same diagnosis and taking the same antiepileptic medication without gait disturbance. On neurological examination, patient and his sister showed the excessive startle and exaggerated reflex myoclonus. Additionally, he also had progressively aggravated muscular stiffness on both lower extremities in his early twenties. Routine blood and CSF laboratory findings, brain MR imaging, EMG and EEG with video monitoring were normal. Genetic studies revealed heterozygous deletion in the GLRA1 exon-1 with autosomal recessive pattern. Instead of previously treated antiepileptic drugs, proband and his sister were treated with low dose of clonazepam and most of neurological symptoms were dramatically improved only after three days of treatment. Conclusions: For now, we reported two siblings with hereditary hyperekplexia caused by heterozygous deletion in the GLRA1 exon-1. Male patient of two siblings showed atypical phenotype that included progressively aggravated muscular hypertonia and stiffness as well as startle symptom. Furthermore, low dose of clonazepam can be a good treatment option for hereditary hyperekplexia. 3.072 AUTISM SPECTRUM DISORDER ASSOCIATED WITH LOW BRAIN SEROTONIN AND MUTATIONS IN THE SEROTONIN TRANSPORTER SLC29A4 AND IN SEROTONIN RELATED GENES D. Adamsen1 , V. Ramaekers2 , R. Bruggmann3 , H. Ho4 , J. Wang4 , B. Thony ¨ 1 . 1 Department of Paediatrics, University of Zurich, Zurich, Switzerland; 2 Division of Pediatric Neurology, University Hospital Liege, Li`ege, Belgium; 3 Functional Genomics Centre Zurich, University of Zurich, Zurich, Switzerland; 4 Department of Pharmaceutics, University of Washington, Seattle, WA, USA Using candidate gene approach and complete exome sequencing, we identified in two unrelated patients with infantile autism and Asperger syndrome associated with reduced brain serotonin turnover a combination of heterozygous mutations in the serotoninrelated genes SLC29A4 and SLC6A4 or ITGB3. Besides the known autism-associated mutations p.L33P in ITGB3 encoding integrin b3, and p.G56A in SLC6A4 encoding elevated activity in SERT, we identified two new mutations p.A138T or p.D326E of the brain monoamine transporter gene SLC29A4 encoding PMAT, a recently described serotonin re-uptake transporter protein. Both mutations lead to reduced function of the PMAT protein. DNA sequencing of SLC29A4/PMAT in 125 individuals with ASD and 300 unaffected (control) subjects revealed the non-synonymous heterozygous alteration p.M24L or p.D29G in 7 additional subjects with ASD (and not in 300 control subjects). According to a hypothetical “genetic accumulation-model” where the affected subjects must differ from non-affected family members (parents and siblings) in the sum of all mutations, the two patients showed additional alterations in mainly serotonin homeostasis, but also other candidate genes that have previously been linked to ASD and/or intellectual disability. Our findings link a combination of mutations in several serotoninrelated genes to ASD concomitant to low serotonin in CNS.
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3.073 EPIGENETIC DNA-METHYLATION IN THE CORE ATAXIN-2 GENE PROMOTER: NOVEL PHYSIOLOGICAL AND PATHOLOGICAL IMPLICATIONS J. Laffita1 , P.O. Bauer2 , V. Kour´ı3 , L. Pena ˜ Serrano4 , J. Roskams5 , 4 D. Almaguer Gotay , J. Aguiar Santiago6 , Y. Gonzalez-Zald´ ´ ıvar4 , L.E. Almaguer Mederos4 , D.A. Cuello-Almarales4 , J.C. Montes Brown4 . 1 Neurobiology, CIRAH, Holguin, Cuba; 2 Laboratory for Structural Neuropathology, Riken Brain Institute, Saitama, Japan; 3 Virology, Institute of Tropical Medicine “Pedro Kour´ı”, Havana, 4 Molecular Neurobiology, CIRAH, Holguin, Cuba; 5 University of British Columbia, Vancouver, BC, Canada; 6 Gene Therapy, Center for Genetic Engineering and Biotechnology (CIGB), Holguin, Cuba Introduction: Pathogenic CAG (Cytosine-Adenine-Guanine) expansions beyond certain thresholds in the ataxin-2 (ATXN2) gene cause spinocerebellar ataxia type 2 (SCA2) and were shown to contribute to Parkinson disease, amyotrophic lateral sclerosis and frontotemporal lobar degeneration. Regulation of ATXN2 gene expression and the function of the protein product are not known. SCA2 exhibits an inverse correlation between the size of the CAG repeat and the age at disease onset. However, a wide range of age at onset is typically observed, with CAG repeat number alone explaining only partly this variability. Objective: In this study, we explored the hypothesis that ATXN2 levels could be controlled by DNA methylation and that the derangement of this control may lead to escalation of disease severity and influencing the age at onset. Results: We found that CpG methylation in human ATXN2 gene promoter is associated with pathogenic CAG expansions in SCA2 patients. Different levels of methylation in a SCA2 pedigree without an intergenerational CAG repeat instability caused the disease anticipation in an SCA2 family. DNA methylation also influenced the disease onset in SCA2 homozygotes and SCA3 patients. Conclusions: In conclusion, our study points to a novel regulatory mechanism of ATXN2 expression involving an epigenetic event resulting in differential disease course in SCA2 patients. 3.074 TRANSCRIPTOME PROFILING OF BLOOD MONONUCLEAR CELLS FROM SCA2 PATIENTS ACCORDING TO CEREBELLAR OR PARKINSONIAN PHENOTYPES C. Simonin1,2 , E. Mutez1,2 , B. Sablonniere ` 3 , A. Duflot1 , M. Figeac1 , F. Lepretre1 , L. Defebvre2 , A. Kreisler1,2 , C. Vanbesien-Mailliot1,4 , D. Devos2 , B. Frigard5 , A. Destee ´ 1,2 , M.-C. Chartier-Harlin1 . 1 JPArc – UMR837 – Team 6, INSERM/Univ Lille, 2 Neurology & Movement Disorders, CHU Lille, 3 JPArc – UMR837 – Team 1, INSERM/Univ Lille, Lille, 4 Neurosciences, University Lille 1/Sciences & Technologies, Villeneuve d’Ascq, 5 CH g´eriatrique, Wasquehal, France Objective: To study genetic and transcriptomic abnormalities associated with cerebellar and parkinsonian phenotypes of spinocerebellar ataxia type 2 (SCA2) using peripheral blood mononuclear cells (PBMC). Background: Except for a suspected role of the length and interruption (by CAA triplets) of the CAG expansion in ataxin-2, little is known about the molecular events leading to parkinsonian or cerebellar phenotype. An implication of ataxin-2 in RNA metabolism has been shown. A better understanding of pathological events might help to find a cure to SCA2 and perhaps to other parkinsonian or cerebellar diseases. Design/Methods: Transcriptomes of 7 parkinsonian and 6 cerebellar patients carrying SCA2 mutations identified by sequencing and 13 age-matched controls were profiled using 2 platforms of whole human genome expression micro-arrays (Agilent and Illumina). Analyses of differential expression in cerebellar and parkinsonian patients vs their respective controls were performed with GeneSpring GX software. Genes with significant differences (fold change >1.3 and Welch t-test p < 0.05) were analyzed using
Wednesday, 14 December 2011 / Parkinsonism and Related Disorders 18S2 (2012) S161–S234
an important copper-transporting P-type ATP-ase. Its dysfunction leads to copper accumulation in the liver and extrahepatic organs such as brain and cornea. Objective: To report a patient with compound heterozygotic ATP7B mutations, already described in WD, but with no clinical manifestation of the disease. Case report: The authors report an adult patient with a longterm history of psychiatric disorders in whom a compound heterozygotic ATP7B mutation, already described in Wilson’s disease (WD) (p.Met645Arg (C1934t>G)/ c.51+4A→T), was found. Hypoceruloplasminemia and hypocupremia were detected but no overt clinical manifestations (hepatic and central nervous system) of WD were present. Conclusion: It is conceivable that some patients might carry a combination of heterozygous mutations, where each mutation encodes distinct parts of exonic and/or intronic zones of ATP7B gene that may eventually lead to a more or less severe functional impairment of copper metabolism and even to no overt clinical hepatic and/or central nervous system manifestations as observed in our patient. 3.068 MOLECULAR GENETIC STUDIES ON INDIAN WILSON’S DISEASE PATIENTS K. Ray1 , S. Mukherjee1 , S. Dutta1 , M. Sengupta1 , P.K. Gangopadhyay2 , A. Bavdekar3 , S.K. Das4 . 1 Molecular & Human Genetics, CSIR-Indian Institute of Chemical Biology, 2 Calcutta National Medical College, Kolkata, 3 King Edward Memorial Hospital, Pune, 4 Bangur Institute of Neurosciences, Kolkata, India Introduction: Wilson’s disease (WD) is an autosomal recessive disorder caused by defects in the ATP7B resulting in accumulation of copper in liver and brain and have overlapping clinical features with other neurological disesaes including Parkinson’s Disease (PD). Identification of mutations in the ATP7B gene is the best way to diagnose WD. Objectives: We aim to identify the molecular bases of WD in Indian patients, attempt to correlate ATP7B genotype with the WD phenotype, examine role of modifier genes and translate the study for the benefit of patients by unequivocal diagnosis of the disease. Materials and Methods: Mostly neurological patients from 177 unrelated Indian families and their first-degree relatives comprising 658 individuals were enrolled in this study. Microsatellite and SNP markers linked to ATP7B were used to build haplotypes and PCRsequencing based approach was taken to identify genetic variants. Results: Both mutations were detected in 102 and single mutation in 57 unrelated WD patients. A total of 8 common (70% of characterized defects) and 52 private mutations were detected. Interestingly, homozygotes for different mutations that would be expected to produce similar disease outcome showed phenotypic heterogeneity including severity of the disease. Conclusions: The common mutations identified in Indian WD patients would aid in detection of carriers and presymptomatic cases with much higher efficiency. Dissection of phenotypic heterogeneity under similar mutation background would let us explore roles of modifier loci. The study is supported by Council of Scientific and Industrial Research (CSIR) Government of India 3.069 EXOME SEQUENCING IDENTIFIES NOVEL SACSIN GENE MUTATIONS IN A CHINESE FAMILY L. Shen1 , Z. Zhan1 , X. Liao1 , Z. Hu1 , J. Wang2 , J. Du1 , B. Tang1 . 1 Department of Neurology, 2 Xiangya Hospital, Central South University, Changsha, China Object: To investigate the disease-causing mutations of a autosomal recessive spastic paraplegia families. Patients and Methods: The two generations non-consanguineous family containing five family members (the proband and her
brother are patients, but her sister and parents are nomal) were rectuited. The probrand, a 39 woman and her brother, a 36 man, suffering from gait disorder, dysarthria, and decreased vision since their early childhood were clinically diagnosed as autosomal recessive spastic paraplegia. Genomic DNA was prepared from venous blood by standard procedures. Direct sequencing had been performed on the proband and mutations of SPG11, SP15, SPG5, SPG7, SPG1, SPG2 had been ruled out. Exome sequencing was carried out on the genomic DNA of the proband and her brother. Bioinformatics analysis, cosegregated analysis and normal matched control analysis were done on the result of exome sequencing to identified the disease-causing mutation. Result: Peripheral lesion and cerebellar atrophy were showed on the proband by electromyologram and MRI scaing, respectively. Exome sequencing confirmed that two patients both had sacsin gene compound heterozygous mutations: c.5840G>G/C, p.P1947R and c.410delT, p.L410XfsX411. These novel variants were at a highly conserved position, were predicted to be damaging, completely cosegregated with the phenotype, and were absent among the 200 geographical matched controls. Conclusion: We identified the first Charlevoix-Saguenay-Spastic Ataxia family in Chinese population and expanded the sacsin gene mutation spectrum. The exome sequencing may be a effective tool for genetic diagnosis of rare autosomal recessive diease. This work was supported the National Natural Science Foundation of China: 30671151, 30971034 3.070 AUTOSOMAL DOMINANT CORTICAL MYOCLONUS AND EPILEPSY (ADCME) – NEW MUTATION IN POLISH FAMILY? S. Budrewicz1 , M. Koszewicz1 , E. Koziorowska-Gawron1 , K. Slotwinski1 , R. Podemski1 , P. Striano2 . 1 Neurology, Wroclaw Medical University, Wroclaw, Poland; 2 Muscular and Neurodegenerative Diseases Unit, University of Genoa, Genoa, Italy ADCME is a disorder of homogenous clinical phenotype, described all over the word, inherited autosomal dominant with high gene penetration, and heterogenic genotypes. In the course of ADCME positional and action tremor, prevailing in upper limbs and sporadic, generalized seizures are observed. The disorder has an unprogressive course. In Polish family, in 3 generations positional and action tremor as well as myoclonus in upper limbs, less pronounced in trunk and lower limbs were observed. Tremor and myoclonus occurred under the age of 20 and were exaggerated by emotions, touch and physical exercises (9 persons presented action and positional tremor, 3 of them had sporadic, epileptic seizures which appeared in older age – the forth decade of life). EMG revealed positional and action tremor with frequency of 7–8 Hz in upper limbs. Generalized slow waves, spike discharges and positive reaction for photostimulation were registered in EEG. In visual evoked potentials (VEP) high amplitude of potential P100 was recorded. There were no positive effect during therapy with beta-blockers or after alcoholic drinks. In genetic studies, in cooperation with the University in Genoa, linkage to chromosome 8, 2, and 5 was excluded. Clinical and electrophysiological data found in Polish family may fulfill criteria of ADCME. We are searching for the new mutation. 3.071 ATYPICAL HEREDITARY HYPEREKPLEXIA CAUSED BY HETEROZYGOUS DELETION MUTATION IN THE GLRA1 EXON-1 W.T. Yoon1 , W.Y. Lee2 , C.-S. Ki3 , J.W. Cho2 . 1 Neurology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, 2 Neurology, 3 Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea Background: Hyperekplexia, also known as startle disease is a rare non-epileptic, neurological disorder characterized by infantile generalized muscular stiffness and excessive startle responses
Wednesday, 14 December 2011 / Parkinsonism and Related Disorders 18S2 (2012) S161–S234
to unexpected acoustic or tactile stimuli. Genetic studies have linked mutations in the gene encoding the alpha-1 subunit of the inhibitory glycine receptor (GLRA1) with hereditary hyperekplexia. Cases: A 23-year-old man presented to us with gait disturbance and the stiffness of both legs seven months ago. He was previously diagnosed as myoclonic epilepsy, taking antiepileptic drugs for 20 years. His older sister, a 34-year-old woman had the same diagnosis and taking the same antiepileptic medication without gait disturbance. On neurological examination, patient and his sister showed the excessive startle and exaggerated reflex myoclonus. Additionally, he also had progressively aggravated muscular stiffness on both lower extremities in his early twenties. Routine blood and CSF laboratory findings, brain MR imaging, EMG and EEG with video monitoring were normal. Genetic studies revealed heterozygous deletion in the GLRA1 exon-1 with autosomal recessive pattern. Instead of previously treated antiepileptic drugs, proband and his sister were treated with low dose of clonazepam and most of neurological symptoms were dramatically improved only after three days of treatment. Conclusions: For now, we reported two siblings with hereditary hyperekplexia caused by heterozygous deletion in the GLRA1 exon-1. Male patient of two siblings showed atypical phenotype that included progressively aggravated muscular hypertonia and stiffness as well as startle symptom. Furthermore, low dose of clonazepam can be a good treatment option for hereditary hyperekplexia. 3.072 AUTISM SPECTRUM DISORDER ASSOCIATED WITH LOW BRAIN SEROTONIN AND MUTATIONS IN THE SEROTONIN TRANSPORTER SLC29A4 AND IN SEROTONIN RELATED GENES D. Adamsen1 , V. Ramaekers2 , R. Bruggmann3 , H. Ho4 , J. Wang4 , B. Thony ¨ 1 . 1 Department of Paediatrics, University of Zurich, Zurich, Switzerland; 2 Division of Pediatric Neurology, University Hospital Liege, Li`ege, Belgium; 3 Functional Genomics Centre Zurich, University of Zurich, Zurich, Switzerland; 4 Department of Pharmaceutics, University of Washington, Seattle, WA, USA Using candidate gene approach and complete exome sequencing, we identified in two unrelated patients with infantile autism and Asperger syndrome associated with reduced brain serotonin turnover a combination of heterozygous mutations in the serotoninrelated genes SLC29A4 and SLC6A4 or ITGB3. Besides the known autism-associated mutations p.L33P in ITGB3 encoding integrin b3, and p.G56A in SLC6A4 encoding elevated activity in SERT, we identified two new mutations p.A138T or p.D326E of the brain monoamine transporter gene SLC29A4 encoding PMAT, a recently described serotonin re-uptake transporter protein. Both mutations lead to reduced function of the PMAT protein. DNA sequencing of SLC29A4/PMAT in 125 individuals with ASD and 300 unaffected (control) subjects revealed the non-synonymous heterozygous alteration p.M24L or p.D29G in 7 additional subjects with ASD (and not in 300 control subjects). According to a hypothetical “genetic accumulation-model” where the affected subjects must differ from non-affected family members (parents and siblings) in the sum of all mutations, the two patients showed additional alterations in mainly serotonin homeostasis, but also other candidate genes that have previously been linked to ASD and/or intellectual disability. Our findings link a combination of mutations in several serotoninrelated genes to ASD concomitant to low serotonin in CNS.
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3.073 EPIGENETIC DNA-METHYLATION IN THE CORE ATAXIN-2 GENE PROMOTER: NOVEL PHYSIOLOGICAL AND PATHOLOGICAL IMPLICATIONS J. Laffita1 , P.O. Bauer2 , V. Kour´ı3 , L. Pena ˜ Serrano4 , J. Roskams5 , 4 D. Almaguer Gotay , J. Aguiar Santiago6 , Y. Gonzalez-Zald´ ´ ıvar4 , L.E. Almaguer Mederos4 , D.A. Cuello-Almarales4 , J.C. Montes Brown4 . 1 Neurobiology, CIRAH, Holguin, Cuba; 2 Laboratory for Structural Neuropathology, Riken Brain Institute, Saitama, Japan; 3 Virology, Institute of Tropical Medicine “Pedro Kour´ı”, Havana, 4 Molecular Neurobiology, CIRAH, Holguin, Cuba; 5 University of British Columbia, Vancouver, BC, Canada; 6 Gene Therapy, Center for Genetic Engineering and Biotechnology (CIGB), Holguin, Cuba Introduction: Pathogenic CAG (Cytosine-Adenine-Guanine) expansions beyond certain thresholds in the ataxin-2 (ATXN2) gene cause spinocerebellar ataxia type 2 (SCA2) and were shown to contribute to Parkinson disease, amyotrophic lateral sclerosis and frontotemporal lobar degeneration. Regulation of ATXN2 gene expression and the function of the protein product are not known. SCA2 exhibits an inverse correlation between the size of the CAG repeat and the age at disease onset. However, a wide range of age at onset is typically observed, with CAG repeat number alone explaining only partly this variability. Objective: In this study, we explored the hypothesis that ATXN2 levels could be controlled by DNA methylation and that the derangement of this control may lead to escalation of disease severity and influencing the age at onset. Results: We found that CpG methylation in human ATXN2 gene promoter is associated with pathogenic CAG expansions in SCA2 patients. Different levels of methylation in a SCA2 pedigree without an intergenerational CAG repeat instability caused the disease anticipation in an SCA2 family. DNA methylation also influenced the disease onset in SCA2 homozygotes and SCA3 patients. Conclusions: In conclusion, our study points to a novel regulatory mechanism of ATXN2 expression involving an epigenetic event resulting in differential disease course in SCA2 patients. 3.074 TRANSCRIPTOME PROFILING OF BLOOD MONONUCLEAR CELLS FROM SCA2 PATIENTS ACCORDING TO CEREBELLAR OR PARKINSONIAN PHENOTYPES C. Simonin1,2 , E. Mutez1,2 , B. Sablonniere ` 3 , A. Duflot1 , M. Figeac1 , F. Lepretre1 , L. Defebvre2 , A. Kreisler1,2 , C. Vanbesien-Mailliot1,4 , D. Devos2 , B. Frigard5 , A. Destee ´ 1,2 , M.-C. Chartier-Harlin1 . 1 JPArc – UMR837 – Team 6, INSERM/Univ Lille, 2 Neurology & Movement Disorders, CHU Lille, 3 JPArc – UMR837 – Team 1, INSERM/Univ Lille, Lille, 4 Neurosciences, University Lille 1/Sciences & Technologies, Villeneuve d’Ascq, 5 CH g´eriatrique, Wasquehal, France Objective: To study genetic and transcriptomic abnormalities associated with cerebellar and parkinsonian phenotypes of spinocerebellar ataxia type 2 (SCA2) using peripheral blood mononuclear cells (PBMC). Background: Except for a suspected role of the length and interruption (by CAA triplets) of the CAG expansion in ataxin-2, little is known about the molecular events leading to parkinsonian or cerebellar phenotype. An implication of ataxin-2 in RNA metabolism has been shown. A better understanding of pathological events might help to find a cure to SCA2 and perhaps to other parkinsonian or cerebellar diseases. Design/Methods: Transcriptomes of 7 parkinsonian and 6 cerebellar patients carrying SCA2 mutations identified by sequencing and 13 age-matched controls were profiled using 2 platforms of whole human genome expression micro-arrays (Agilent and Illumina). Analyses of differential expression in cerebellar and parkinsonian patients vs their respective controls were performed with GeneSpring GX software. Genes with significant differences (fold change >1.3 and Welch t-test p < 0.05) were analyzed using