Journal of the Neurological Sciences 347 (2014) 322–324
Contents lists available at ScienceDirect
Journal of the Neurological Sciences journal homepage: www.elsevier.com/locate/jns
C9ORF72 repeat expansion is not a significant cause of late onset cerebellar ataxia syndrome Cheng-Tsung Hsiao a,b, Pei-Chien Tsai a,b,c, Yi-Chu Liao a,b,c, Yi-Chung Lee a,b,c, Bing-Wen Soong a,b,c,⁎ a b c
Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan Department of Neurology, National Yang-Ming University School of Medicine, Taipei, Taiwan Brain Research Center, National Yang-Ming University, Taipei, Taiwan
a r t i c l e
i n f o
Article history: Received 19 June 2014 Received in revised form 7 October 2014 Accepted 30 October 2014 Available online 6 November 2014 Keywords: C9ORF72 Spinocerebellar ataxia Multiple system atrophy
a b s t r a c t The GGGGCC hexanucleotide expansion in the C9ORF72 gene is the most common cause of familial amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) in Caucasian populations. The phenotypic spectrum of C9ORF72 hexanucleotide repeat expansion mutation has been reported to include parkinsonian syndrome, Huntington's disease-like syndrome and dementia syndrome. Although few individuals with cerebellar ataxia have also anecdotally been found to harbor the mutation, the relationship between the mutation and cerebellar ataxia awaits further clarification. We hereby screened for the presence of the C9ORF72 hexanucleotide repeat expansion in 331 patients with multiple system atrophy-cerebellar variant and 98 unrelated patients with molecularly un-assigned spinocerebellar ataxia in Taiwan utilizing a repeat-primed polymerase chain reaction assay. We found that none of the 429 patients had the C9ORF72 hexanucleotide repeat expansion mutation. Therefore, our study does not support that the mutation plays a significant role in cerebellar ataxia. © 2014 Published by Elsevier B.V.
1. Introduction A GGGGCC hexanucleotide repeat expansion mutation in the intron between non-coding exons 1a and 1b of the C9ORF72 gene has been initially demonstrated to be a common cause of familial amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) in Caucasian populations [1–3]. The phenotypic spectrum of the mutation has rapidly expanded with subsequent studies to include parkinsonian syndrome, Huntington's disease-like syndrome and dementia syndrome [4–7]. Intriguingly, several individuals with cerebellar ataxia have also been reported to harbor the C9ORF72 hexanucleotide repeat expansion mutation [8–10]. Still, the relationship between the mutation and cerebellar ataxia awaits further elucidation. The hypothesis that the C9ORF72 hexanucleotide repeat expansion mutation might possibly play a role in cerebellar ataxia was brought up based on the following observations. First, the p62 positive and TAR DNA binding protein (TDP-43) negative cytoplasmic inclusions in the hippocampus as well as the cerebellum is pathognomonic for patients with C9ORF72 hexanucleotide repeat expansion manifesting ALS, FTD, or ALS/FTD [11,12]. Second, a significant atrophy of the cerebellum was proposed as a useful clue to differentiate patients with
⁎ Corresponding author at: Department Neurology, National Yang-Ming University School of Medicine, #155, Section 2, Linung Street, Peitou District, Taipei 112, Taiwan. Tel.: +886 2 2872 7577. E-mail address: [email protected] (B.-W. Soong).
http://dx.doi.org/10.1016/j.jns.2014.10.042 0022-510X/© 2014 Published by Elsevier B.V.
FTD and C9ORF72 hexanucleotide repeat expansion mutation from those without the mutation [13]. Herein, we screened for the hexanucleotide repeat mutation in C9ORF72 in large cohorts of Chinese patients with idiopathic lateonset cerebellar ataxia and healthy controls in Taiwan. 2. Subjects and methods The protocol for this study was approved by the institutional review board of Taipei Veterans General Hospital. Written informed consents were obtained from all participants. Three hundred and thirty one patients with MSA-C, 98 unrelated patients with molecularly unassigned SCA, and 323 unselected healthy controls were enlisted. The diagnosis of MSA-C was made according to the following criteria: (1) a clinical history of sporadic and progressive ataxia, (2) definitive evidence of autonomic failure for “probable” MSA-C, or features suggesting autonomic dysfunction for “possible” MSA-C, (3) exclusion of trinucleotide repeat expansion mutations in ATXN1, ATXN2, ATXN3, CACNA1A and TATA box binding protein gene [14]. Among the patients with SCA, 75 had autosomal dominant inheritance and 23 had apparently autosomal recessive diseases. The patients with at least one symptomatic sibling and asymptomatic parents were categorized into the apparently autosomal recessive group. SCA1, 2, 3, 6, 7, 8, 10, 12, 17, 22, 31, 35, 36 and dentatorubral-pallidoluysian atrophy (DRPLA) had been excluded in all the SCA patients by extensive genetic testing. We ascertained the GGGGCC hexanucleotide repeat expansion by the method previously described [15]. In brief, the hexanucleotide
C.-T. Hsiao et al. / Journal of the Neurological Sciences 347 (2014) 322–324
repeat region in C9ORF72 was PCR amplified using primers with one of them fluorescently labeled. Fragment length analysis was conducted on an ABI Prism 3700 Genetic Analyzer. Because the alleles with an expanded hexanucleotide repeat are usually too large to be amplified by conventional PCR, the patients with only one single allele in the fragment length analysis were further investigated using the repeat-primed PCR method [1,2]. The amplicons generated by the repeat-primed PCR from an expanded repeat would give rise to a characteristic sawtooth pattern with a 6-bp periodicity on the electropheregram. The genomic DNA of a patient with ALS and the C9ORF72 hexanucleotide repeat expansion mutation was used as a positive control [15]. 3. Results The demographic features of the patients in this study were summarized in supplemental table 1. In our case cohorts, the length of the hexanucleotide repeat in C9ORF72 ranged from 3 to 15 (Fig. 1). Most of the participants (37.06%) harbored 3 repeats. Another cluster of hexanucleotide repeats ranged between 7 and 12. The clustering patterns of hexanucleotide repeats in C9ORF72 were of no difference between the unselected healthy controls and the patients. The largest size of C9ORF72 hexanucleotide repeat was 15 (3 of 429 participants, 0.70%) in the patient cohort. Pathological hexanucleotide repeat expansion (≧31 repeats) was not found in C9ORF72 in any of the cohorts studied. 4. Discussion We looked for the C9ORF72 hexanucleotide repeat expansion in 331 patients with MSA-C, 98 patients with idiopathic SCA and 323 unselected healthy controls and found that none of them carried the mutation. These results indicate that the C9ORF72 hexanucleotide repeat expansion mutation does not play a significant role in cerebellar ataxia. Several explanations might be plausible. First, the co-occurrence of the C9ORF72 mutation and cerebellar ataxia in the few previously reported cases [8–10] might have just been co-incidences. Second, a weaker expressivity to manifest ALS might explain the absence of the signs of motor neuron disease (MND) in those cases. Third, the penetrance of the C9ORF72 hexanucleotide repeat expansion has been shown to be incomplete and variable in most ALS/FTD pedigrees [5]. The penetrance of this mutation increased with age and was estimated to be 0 in the third decade, 0.5 in the fifth decade, and 1 in the eighth decade [16]. In the families of the previously reported three cases with the C9ORF72 hexanucleotide repeat expansion mutation and cerebellar ataxia, no other member with verified C9ORF72 mutation had cerebellar ataxia [8–10]. One patient was clinically diagnosed to have olivopontocerebellar degeneration at first and years later
323
developed signs of MND and frontotemporal atrophy on neuroimages [10]. It is reasonable to assume that that case might have an agedependent and incomplete penetrance, in terms of MND, at the younger age and coincidentally a sporadic ataxia phenotype. Another pedigree had a family history of MND and the index case developed cerebellar ataxia in her second decade and upper motor neuron signs in the fifth decade [8]. The prospect of developing lower motor neuron signs remained uncertain. In the third case with a family history of MND [9] the sibling and father both had a classic and pure MND phenotype and only the index case had symptoms of cerebellar ataxia and parkinsonism [9]. None of the three cases with both C9ORF72 hexanucleotide repeat expansion mutation and cerebellar ataxia provided unequivocal evidence to support their association. The C9ORF72 hexanucleotide repeat expansion might, at most, only play a minor role in cerebellar ataxia, and the rarity of the co-occurrence of the mutation and cerebellar ataxia suggests that other environmental or genetic modifiers are influencing the manifestation. For example, in the case reported by Goldman, et al. [9], other environmental or genetic modifiers might have contributed to the pathological process of C9ORF72 mutation. Recently, transmembrane protein 106B (TMEM106B) was reported to be a genetic modifier of C9ORF72 hexanucleotide repeat expansion mutation in FTD [17]. Whether there is a genetic modifier affecting the C9ORF72 expansion mutation in ataxia remains enigmatic. Although we are not able to absolutely exclude the possibility that the C9ORF72 hexanucleotide repeat expansion mutation might still be one of the rare causes of cerebellar ataxia syndrome, several facts are against this possibility, including the low prevalence of the mutation in sporadic late onset ataxia syndrome in another study (one out of 209) [8], the absence of available example of co-segregation of the mutation and cerebellar ataxia in the literature and the absence of the mutation in a large cohort of patients with MSA-C or SCA in our study. In conclusion, the C9ORF72 hexanucleotide repeat expansion mutation is extremely rare in patients with cerebellar ataxia. Our finding does not support that the mutation plays any significant role in cerebellar ataxia. Supplementary data to this article can be found online at http://dx. doi.org/10.1016/j.jns.2014.10.042. Disclosure statement The authors declare no conflicts of interest. The protocol for this study was approved by the Institutional Review Board of Taipei Veterans General Hospital. Written informed consents were obtained from all of the participants. Acknowledgments The authors thank the patients who participated in this study. This work was supported by grants from the National Science Council, Taiwan (NSC99-2314-B-010-013-MY3, NSC100-2314-B-075-020MY2), Taipei Veterans General Hospital (V100C-008, V102C-124), and the Ministry of Education, Aim for the Top University Plan (V100-E6006 and V101-E7-005), and the High-throughput Genome Analysis Core Facility of National Core Facility Program for Biotechnology, Taiwan (NSC-100-2319-B-010-001), as well as the research funds from the Taiwan Ataxia Association and the Hsu Tsung Pei Medical Research Fund. References
Fig. 1. The length of C9ORF72 hexanucleotide repeats in the study cohorts and healthy controls: Most participants harbored 3 GGGGCC hexanucleotide repeats in C9ORF72. Another cluster with a repeat size ranging from 7 to 12 was also observed. The largest repeat size was 15.
[1] DeJesus-Hernandez M, Mackenzie IR, Boeve BF, Boxer AL, Baker M, Rutherford NJ, et al. Expanded GGGGCC hexanucleotide repeat in noncoding region of C9ORF72 causes chromosome 9p-linked FTD and ALS. Neuron 2011;72(2):245–56. [2] Renton AE, Majounie E, Waite A, Simon-Sanchez J, Rollinson S, Gibbs JR, et al. A hexanucleotide repeat expansion in C9ORF72 is the cause of chromosome 9p21linked ALS-FTD. Neuron 2011;72(2):257–68. [3] Gijselinck I, Van Langenhove T, van der Zee J, Sleegers K, Philtjens S, Kleinberger G, et al. A C9ORF72 promoter repeat expansion in a Flanders–Belgian cohort with
324
[4]
[5]
[6] [7]
[8]
[9]
[10]
C.-T. Hsiao et al. / Journal of the Neurological Sciences 347 (2014) 322–324 disorders of the frontotemporal lobar degeneration-amyotrophic lateral sclerosis spectrum: a gene identification study. Lancet Neurol 2012;11(1):54–65. Davina J, Moss Hensman, Poulter Mark, Beck Jon, Hehir Jason, Polke James M, Campbell Tracy, et al. C9ORF72 expansions are the most common genetic cause of Huntington disease phenocopies. Neurology 2014;82(19):292–9. Beck J, Poulter M, Hensman D, Rohrer JD, Mahoney CJ, Adamson G, et al. Large C9ORF72 hexanucleotide repeat expansions are seen in multiple neurodegenerative syndromes and are more frequent than expected in the UK population. Am J Hum Genet 2013;92(3):345–53. Majounie E, Abramzon Y, Renton AE, Perry R, Bassett SS, Pletnikova O, et al. Repeat expansion in C9ORF72 in Alzheimer's disease. N Engl J Med 2012;366(3):283–4. Cooper-Knock J, Shaw PJ, Kirby J. The widening spectrum of C9ORF72-related disease; genotype/phenotype correlations and potential modifiers of clinical phenotype. Acta Neuropathol 2014;127(3):333–45. Fogel BL, Pribadi M, Pi S, Perlman SL, Geschwind DH, Coppola G. C9ORF72 expansion is not a significant cause of sporadic spinocerebellar ataxia. Mov Disord 2012; 27(14):1832–3. Goldman JS, Quinzii C, Dunning-Broadbent J, Waters C, Mitsumoto H, Brannagan III TH, et al. Multiple system atrophy and amyotrophic lateral sclerosis in a family with hexanucleotide repeat expansions in C9ORF72. JAMA Neurol 2014;71(6): 771–4. Lindquist SG, Duno M, Batbayli M, Puschmann A, Braendgaard H, Mardosiene S, et al. Corticobasal and ataxia syndromes widen the spectrum of C9ORF72 hexanucleotide expansion disease. Clin Genet 2013;83(3):279–83.
[11] Al-Sarraj S, King A, Troakes C, Smith B, Maekawa S, Bodi I, et al. p62 positive, TDP-43 negative, neuronal cytoplasmic and intranuclear inclusions in the cerebellum and hippocampus define the pathology of C9ORF72-linked FTLD and MND/ALS. Acta Neuropathol 2011;122(6):691–702. [12] Mori K, Lammich S, Mackenzie IR, Forne I, Zilow S, Kretzschmar H, et al. hnRNP A3 binds to GGGGCC repeats and is a constituent of p62-positive/TDP43-negative inclusions in the hippocampus of patients with C9ORF72 mutations. Acta Neuropathol 2013;125(3):413–23. [13] Whitwell JL, Weigand SD, Boeve BF, Senjem ML, Gunter JL, DeJesus-Hernandez M, et al. Neuroimaging signatures of frontotemporal dementia genetics: C9ORF72, tau, progranulin and sporadics. Brain 2012;135(Pt 3):794–806. [14] Lee YC, Liao YC, Wang PS, Lee IH, Lin KP, Soong BW. Comparison of cerebellar ataxias: a three-year prospective longitudinal assessment. Mov Disord 2011; 26(11):2081–7. [15] Tsai CP, Soong BW, Tu PH, Lin KP, Fuh JL, Tsai PC, et al. A hexanucleotide repeat expansion in C9ORF72 causes familial and sporadic ALS in Taiwan. Neurobiol Aging 2012;33(9):e11–8. [16] Majounie E, Renton A, Mok K, Dopper E, Waite A, Rollinson S, et al. Frequency of the C9ORF72 hexanucleotide repeat expansion in patients with amyotrophic lateral sclerosis and frontotemporal dementia: a cross-sectional study. Lancet Neurol 2012;11(4):323–30. [17] van Blitterswijk M, Mullen B, Nicholson AM, Bieniek KF, Heckman MG, Baker MC, et al. TMEM106B protects C9ORF72 expansion carriers against frontotemporal dementia. Acta Neuropathol 2014;127(3):397–406.
Contents lists available at ScienceDirect
Journal of the Neurological Sciences journal homepage: www.elsevier.com/locate/jns
C9ORF72 repeat expansion is not a significant cause of late onset cerebellar ataxia syndrome Cheng-Tsung Hsiao a,b, Pei-Chien Tsai a,b,c, Yi-Chu Liao a,b,c, Yi-Chung Lee a,b,c, Bing-Wen Soong a,b,c,⁎ a b c
Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan Department of Neurology, National Yang-Ming University School of Medicine, Taipei, Taiwan Brain Research Center, National Yang-Ming University, Taipei, Taiwan
a r t i c l e
i n f o
Article history: Received 19 June 2014 Received in revised form 7 October 2014 Accepted 30 October 2014 Available online 6 November 2014 Keywords: C9ORF72 Spinocerebellar ataxia Multiple system atrophy
a b s t r a c t The GGGGCC hexanucleotide expansion in the C9ORF72 gene is the most common cause of familial amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) in Caucasian populations. The phenotypic spectrum of C9ORF72 hexanucleotide repeat expansion mutation has been reported to include parkinsonian syndrome, Huntington's disease-like syndrome and dementia syndrome. Although few individuals with cerebellar ataxia have also anecdotally been found to harbor the mutation, the relationship between the mutation and cerebellar ataxia awaits further clarification. We hereby screened for the presence of the C9ORF72 hexanucleotide repeat expansion in 331 patients with multiple system atrophy-cerebellar variant and 98 unrelated patients with molecularly un-assigned spinocerebellar ataxia in Taiwan utilizing a repeat-primed polymerase chain reaction assay. We found that none of the 429 patients had the C9ORF72 hexanucleotide repeat expansion mutation. Therefore, our study does not support that the mutation plays a significant role in cerebellar ataxia. © 2014 Published by Elsevier B.V.
1. Introduction A GGGGCC hexanucleotide repeat expansion mutation in the intron between non-coding exons 1a and 1b of the C9ORF72 gene has been initially demonstrated to be a common cause of familial amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) in Caucasian populations [1–3]. The phenotypic spectrum of the mutation has rapidly expanded with subsequent studies to include parkinsonian syndrome, Huntington's disease-like syndrome and dementia syndrome [4–7]. Intriguingly, several individuals with cerebellar ataxia have also been reported to harbor the C9ORF72 hexanucleotide repeat expansion mutation [8–10]. Still, the relationship between the mutation and cerebellar ataxia awaits further elucidation. The hypothesis that the C9ORF72 hexanucleotide repeat expansion mutation might possibly play a role in cerebellar ataxia was brought up based on the following observations. First, the p62 positive and TAR DNA binding protein (TDP-43) negative cytoplasmic inclusions in the hippocampus as well as the cerebellum is pathognomonic for patients with C9ORF72 hexanucleotide repeat expansion manifesting ALS, FTD, or ALS/FTD [11,12]. Second, a significant atrophy of the cerebellum was proposed as a useful clue to differentiate patients with
⁎ Corresponding author at: Department Neurology, National Yang-Ming University School of Medicine, #155, Section 2, Linung Street, Peitou District, Taipei 112, Taiwan. Tel.: +886 2 2872 7577. E-mail address: [email protected] (B.-W. Soong).
http://dx.doi.org/10.1016/j.jns.2014.10.042 0022-510X/© 2014 Published by Elsevier B.V.
FTD and C9ORF72 hexanucleotide repeat expansion mutation from those without the mutation [13]. Herein, we screened for the hexanucleotide repeat mutation in C9ORF72 in large cohorts of Chinese patients with idiopathic lateonset cerebellar ataxia and healthy controls in Taiwan. 2. Subjects and methods The protocol for this study was approved by the institutional review board of Taipei Veterans General Hospital. Written informed consents were obtained from all participants. Three hundred and thirty one patients with MSA-C, 98 unrelated patients with molecularly unassigned SCA, and 323 unselected healthy controls were enlisted. The diagnosis of MSA-C was made according to the following criteria: (1) a clinical history of sporadic and progressive ataxia, (2) definitive evidence of autonomic failure for “probable” MSA-C, or features suggesting autonomic dysfunction for “possible” MSA-C, (3) exclusion of trinucleotide repeat expansion mutations in ATXN1, ATXN2, ATXN3, CACNA1A and TATA box binding protein gene [14]. Among the patients with SCA, 75 had autosomal dominant inheritance and 23 had apparently autosomal recessive diseases. The patients with at least one symptomatic sibling and asymptomatic parents were categorized into the apparently autosomal recessive group. SCA1, 2, 3, 6, 7, 8, 10, 12, 17, 22, 31, 35, 36 and dentatorubral-pallidoluysian atrophy (DRPLA) had been excluded in all the SCA patients by extensive genetic testing. We ascertained the GGGGCC hexanucleotide repeat expansion by the method previously described [15]. In brief, the hexanucleotide
C.-T. Hsiao et al. / Journal of the Neurological Sciences 347 (2014) 322–324
repeat region in C9ORF72 was PCR amplified using primers with one of them fluorescently labeled. Fragment length analysis was conducted on an ABI Prism 3700 Genetic Analyzer. Because the alleles with an expanded hexanucleotide repeat are usually too large to be amplified by conventional PCR, the patients with only one single allele in the fragment length analysis were further investigated using the repeat-primed PCR method [1,2]. The amplicons generated by the repeat-primed PCR from an expanded repeat would give rise to a characteristic sawtooth pattern with a 6-bp periodicity on the electropheregram. The genomic DNA of a patient with ALS and the C9ORF72 hexanucleotide repeat expansion mutation was used as a positive control [15]. 3. Results The demographic features of the patients in this study were summarized in supplemental table 1. In our case cohorts, the length of the hexanucleotide repeat in C9ORF72 ranged from 3 to 15 (Fig. 1). Most of the participants (37.06%) harbored 3 repeats. Another cluster of hexanucleotide repeats ranged between 7 and 12. The clustering patterns of hexanucleotide repeats in C9ORF72 were of no difference between the unselected healthy controls and the patients. The largest size of C9ORF72 hexanucleotide repeat was 15 (3 of 429 participants, 0.70%) in the patient cohort. Pathological hexanucleotide repeat expansion (≧31 repeats) was not found in C9ORF72 in any of the cohorts studied. 4. Discussion We looked for the C9ORF72 hexanucleotide repeat expansion in 331 patients with MSA-C, 98 patients with idiopathic SCA and 323 unselected healthy controls and found that none of them carried the mutation. These results indicate that the C9ORF72 hexanucleotide repeat expansion mutation does not play a significant role in cerebellar ataxia. Several explanations might be plausible. First, the co-occurrence of the C9ORF72 mutation and cerebellar ataxia in the few previously reported cases [8–10] might have just been co-incidences. Second, a weaker expressivity to manifest ALS might explain the absence of the signs of motor neuron disease (MND) in those cases. Third, the penetrance of the C9ORF72 hexanucleotide repeat expansion has been shown to be incomplete and variable in most ALS/FTD pedigrees [5]. The penetrance of this mutation increased with age and was estimated to be 0 in the third decade, 0.5 in the fifth decade, and 1 in the eighth decade [16]. In the families of the previously reported three cases with the C9ORF72 hexanucleotide repeat expansion mutation and cerebellar ataxia, no other member with verified C9ORF72 mutation had cerebellar ataxia [8–10]. One patient was clinically diagnosed to have olivopontocerebellar degeneration at first and years later
323
developed signs of MND and frontotemporal atrophy on neuroimages [10]. It is reasonable to assume that that case might have an agedependent and incomplete penetrance, in terms of MND, at the younger age and coincidentally a sporadic ataxia phenotype. Another pedigree had a family history of MND and the index case developed cerebellar ataxia in her second decade and upper motor neuron signs in the fifth decade [8]. The prospect of developing lower motor neuron signs remained uncertain. In the third case with a family history of MND [9] the sibling and father both had a classic and pure MND phenotype and only the index case had symptoms of cerebellar ataxia and parkinsonism [9]. None of the three cases with both C9ORF72 hexanucleotide repeat expansion mutation and cerebellar ataxia provided unequivocal evidence to support their association. The C9ORF72 hexanucleotide repeat expansion might, at most, only play a minor role in cerebellar ataxia, and the rarity of the co-occurrence of the mutation and cerebellar ataxia suggests that other environmental or genetic modifiers are influencing the manifestation. For example, in the case reported by Goldman, et al. [9], other environmental or genetic modifiers might have contributed to the pathological process of C9ORF72 mutation. Recently, transmembrane protein 106B (TMEM106B) was reported to be a genetic modifier of C9ORF72 hexanucleotide repeat expansion mutation in FTD [17]. Whether there is a genetic modifier affecting the C9ORF72 expansion mutation in ataxia remains enigmatic. Although we are not able to absolutely exclude the possibility that the C9ORF72 hexanucleotide repeat expansion mutation might still be one of the rare causes of cerebellar ataxia syndrome, several facts are against this possibility, including the low prevalence of the mutation in sporadic late onset ataxia syndrome in another study (one out of 209) [8], the absence of available example of co-segregation of the mutation and cerebellar ataxia in the literature and the absence of the mutation in a large cohort of patients with MSA-C or SCA in our study. In conclusion, the C9ORF72 hexanucleotide repeat expansion mutation is extremely rare in patients with cerebellar ataxia. Our finding does not support that the mutation plays any significant role in cerebellar ataxia. Supplementary data to this article can be found online at http://dx. doi.org/10.1016/j.jns.2014.10.042. Disclosure statement The authors declare no conflicts of interest. The protocol for this study was approved by the Institutional Review Board of Taipei Veterans General Hospital. Written informed consents were obtained from all of the participants. Acknowledgments The authors thank the patients who participated in this study. This work was supported by grants from the National Science Council, Taiwan (NSC99-2314-B-010-013-MY3, NSC100-2314-B-075-020MY2), Taipei Veterans General Hospital (V100C-008, V102C-124), and the Ministry of Education, Aim for the Top University Plan (V100-E6006 and V101-E7-005), and the High-throughput Genome Analysis Core Facility of National Core Facility Program for Biotechnology, Taiwan (NSC-100-2319-B-010-001), as well as the research funds from the Taiwan Ataxia Association and the Hsu Tsung Pei Medical Research Fund. References
Fig. 1. The length of C9ORF72 hexanucleotide repeats in the study cohorts and healthy controls: Most participants harbored 3 GGGGCC hexanucleotide repeats in C9ORF72. Another cluster with a repeat size ranging from 7 to 12 was also observed. The largest repeat size was 15.
[1] DeJesus-Hernandez M, Mackenzie IR, Boeve BF, Boxer AL, Baker M, Rutherford NJ, et al. Expanded GGGGCC hexanucleotide repeat in noncoding region of C9ORF72 causes chromosome 9p-linked FTD and ALS. Neuron 2011;72(2):245–56. [2] Renton AE, Majounie E, Waite A, Simon-Sanchez J, Rollinson S, Gibbs JR, et al. A hexanucleotide repeat expansion in C9ORF72 is the cause of chromosome 9p21linked ALS-FTD. Neuron 2011;72(2):257–68. [3] Gijselinck I, Van Langenhove T, van der Zee J, Sleegers K, Philtjens S, Kleinberger G, et al. A C9ORF72 promoter repeat expansion in a Flanders–Belgian cohort with
324
[4]
[5]
[6] [7]
[8]
[9]
[10]
C.-T. Hsiao et al. / Journal of the Neurological Sciences 347 (2014) 322–324 disorders of the frontotemporal lobar degeneration-amyotrophic lateral sclerosis spectrum: a gene identification study. Lancet Neurol 2012;11(1):54–65. Davina J, Moss Hensman, Poulter Mark, Beck Jon, Hehir Jason, Polke James M, Campbell Tracy, et al. C9ORF72 expansions are the most common genetic cause of Huntington disease phenocopies. Neurology 2014;82(19):292–9. Beck J, Poulter M, Hensman D, Rohrer JD, Mahoney CJ, Adamson G, et al. Large C9ORF72 hexanucleotide repeat expansions are seen in multiple neurodegenerative syndromes and are more frequent than expected in the UK population. Am J Hum Genet 2013;92(3):345–53. Majounie E, Abramzon Y, Renton AE, Perry R, Bassett SS, Pletnikova O, et al. Repeat expansion in C9ORF72 in Alzheimer's disease. N Engl J Med 2012;366(3):283–4. Cooper-Knock J, Shaw PJ, Kirby J. The widening spectrum of C9ORF72-related disease; genotype/phenotype correlations and potential modifiers of clinical phenotype. Acta Neuropathol 2014;127(3):333–45. Fogel BL, Pribadi M, Pi S, Perlman SL, Geschwind DH, Coppola G. C9ORF72 expansion is not a significant cause of sporadic spinocerebellar ataxia. Mov Disord 2012; 27(14):1832–3. Goldman JS, Quinzii C, Dunning-Broadbent J, Waters C, Mitsumoto H, Brannagan III TH, et al. Multiple system atrophy and amyotrophic lateral sclerosis in a family with hexanucleotide repeat expansions in C9ORF72. JAMA Neurol 2014;71(6): 771–4. Lindquist SG, Duno M, Batbayli M, Puschmann A, Braendgaard H, Mardosiene S, et al. Corticobasal and ataxia syndromes widen the spectrum of C9ORF72 hexanucleotide expansion disease. Clin Genet 2013;83(3):279–83.
[11] Al-Sarraj S, King A, Troakes C, Smith B, Maekawa S, Bodi I, et al. p62 positive, TDP-43 negative, neuronal cytoplasmic and intranuclear inclusions in the cerebellum and hippocampus define the pathology of C9ORF72-linked FTLD and MND/ALS. Acta Neuropathol 2011;122(6):691–702. [12] Mori K, Lammich S, Mackenzie IR, Forne I, Zilow S, Kretzschmar H, et al. hnRNP A3 binds to GGGGCC repeats and is a constituent of p62-positive/TDP43-negative inclusions in the hippocampus of patients with C9ORF72 mutations. Acta Neuropathol 2013;125(3):413–23. [13] Whitwell JL, Weigand SD, Boeve BF, Senjem ML, Gunter JL, DeJesus-Hernandez M, et al. Neuroimaging signatures of frontotemporal dementia genetics: C9ORF72, tau, progranulin and sporadics. Brain 2012;135(Pt 3):794–806. [14] Lee YC, Liao YC, Wang PS, Lee IH, Lin KP, Soong BW. Comparison of cerebellar ataxias: a three-year prospective longitudinal assessment. Mov Disord 2011; 26(11):2081–7. [15] Tsai CP, Soong BW, Tu PH, Lin KP, Fuh JL, Tsai PC, et al. A hexanucleotide repeat expansion in C9ORF72 causes familial and sporadic ALS in Taiwan. Neurobiol Aging 2012;33(9):e11–8. [16] Majounie E, Renton A, Mok K, Dopper E, Waite A, Rollinson S, et al. Frequency of the C9ORF72 hexanucleotide repeat expansion in patients with amyotrophic lateral sclerosis and frontotemporal dementia: a cross-sectional study. Lancet Neurol 2012;11(4):323–30. [17] van Blitterswijk M, Mullen B, Nicholson AM, Bieniek KF, Heckman MG, Baker MC, et al. TMEM106B protects C9ORF72 expansion carriers against frontotemporal dementia. Acta Neuropathol 2014;127(3):397–406.
