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Nunes Gonçalves JP, Leoni TB, Martins MP, Peluzzo TM, Dourado MET, Saute JAM, Paranhos Miranda Covaleski AP, Bulle de Oliveira AS, Claudino R, Marques W, Nucci A, França MC. Genetic epidemiology of familial ALS in Brazil. Neurobiol Aging 2021; 102:227.e1-227.e4. [PMID: 33618928 DOI: 10.1016/j.neurobiolaging.2021.01.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Revised: 12/03/2020] [Accepted: 01/09/2021] [Indexed: 01/11/2023]
Abstract
Many genes associated with familial forms of the amyotrophic lateral sclerosis (fALS) have been identified in European and North American cohorts. However, little is known about the genetic bases of fALS in Latin America and Brazil, in particular. To address this question, we recruited 107 patients with fALS from 93 unrelated families from Southeastern, Southern, and Northeastern regions of the country. A 3-step diagnostic approach was used: 1) Triplet repeat primed polymerase chain reaction to search for C9orf72 expansions, then 2) fragment digestion to search for the c.166 C>T VAPB variant, and finally, 3) whole exome sequencing for those who tested negative. We identified the genetic cause for fALS in 70% of the families. VAPB and C9orf72 were the most frequent genes (30% and 22%, respectively), followed by SOD1, TARDBP, ANXA11, and FUS. Five novel variants in known ALS genes were found, including the SOD1 Val120Leu and ANXA11 Asp40Tyr, which were seen in 2 unrelated families each. In conclusion, VAPB and then C9orf72 are the genes most commonly related to fALS in Brazil.
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Affiliation(s)
- João Pedro Nunes Gonçalves
- Departments of Neurology and Medical Genetics, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, BRAZIL
| | - Tauana Bernardes Leoni
- Departments of Neurology and Medical Genetics, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, BRAZIL
| | - Melina Pazian Martins
- Departments of Neurology and Medical Genetics, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, BRAZIL
| | - Thiago Mazzo Peluzzo
- Departments of Neurology and Medical Genetics, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, BRAZIL
| | - Mario Emílio T Dourado
- Department of Integrative Medicine, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Jonas Alex M Saute
- Department of Internal Medicine, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | | | | | - Rinaldo Claudino
- Department of Neurology, Federal University of Santa Catarina, Florianópolis, Brazil
| | - Wilson Marques
- Department of Neurosciences and Behavior Sciences, Ribeirão Preto School of Medicine, University of São Paulo (HCFMRP-USP), Ribeirão Preto, Brazil
| | - Anamarli Nucci
- Departments of Neurology and Medical Genetics, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, BRAZIL
| | - Marcondes C França
- Departments of Neurology and Medical Genetics, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, BRAZIL.
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Peluzzo TM, Bonadia LC, Donatti A, Molck MC, Jardim LB, Marques W, Lopes-Cendes IT, França MC. Frequency and Genetic Profile of Compound Heterozygous Friedreich's Ataxia Patients-the Brazilian Experience. Cerebellum 2019; 18:1143-1146. [PMID: 31243663 DOI: 10.1007/s12311-019-01055-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Friedreich ataxia (FRDA) is the most common autosomal recessive ataxia in Caucasian populations. It is caused by a homozygous GAA expansion in the first intron of the frataxin gene (FXN) (OMIM: 606829) in 96% of the affected individuals. The remaining patients have a GAA expansion in one allele and a point mutation in the other. Little is known about compound heterozygous patients outside Europe and North America. We have thus designed a study to determine the frequency and mutational profile of these patients in Brazil. To accomplish that, we recruited all patients with ataxia and at least one expanded GAA allele at FXN from 3 national reference centers. We identified those subjects with a single expansion and proceeded with further genetic testing (Sanger sequencing and CGH arrays) for those. There were 143 unrelated patients (128 families), five of which had a single expanded allele. We identified point mutations in three out of these five (3/128 = 2.34%). Two patients had the c.157delC variant, whereas one individual had the novel variant c.482+1G>T. These results indicate that FXN point mutations are rare, but exist in Brazilian patients with FRDA. This has obvious implications for diagnostic testing and genetic counseling.
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Affiliation(s)
- Thiago Mazzo Peluzzo
- Department of Medical Genetics and Genomic Medicine, School of Medicine, University of Campinas - UNICAMP, Rua Tessália Vieira de Camargo, 126, Cidade Universitaria "Zeferino Vaz", Campinas, SP, 13083-887, Brazil
| | - Luciana Cardoso Bonadia
- Department of Medical Genetics and Genomic Medicine, School of Medicine, University of Campinas - UNICAMP, Rua Tessália Vieira de Camargo, 126, Cidade Universitaria "Zeferino Vaz", Campinas, SP, 13083-887, Brazil
| | - Amanda Donatti
- Department of Medical Genetics and Genomic Medicine, School of Medicine, University of Campinas - UNICAMP, Rua Tessália Vieira de Camargo, 126, Cidade Universitaria "Zeferino Vaz", Campinas, SP, 13083-887, Brazil
| | - Miriam Coelho Molck
- Department of Medical Genetics and Genomic Medicine, School of Medicine, University of Campinas - UNICAMP, Rua Tessália Vieira de Camargo, 126, Cidade Universitaria "Zeferino Vaz", Campinas, SP, 13083-887, Brazil
| | - Laura Bannach Jardim
- Medical Genetics Service, Hospital de Clínicas de Porto Alegre, Rua Ramiro Barcelos, 2350, Porto Alegre, RS, 90035-003, Brazil
| | - Wilson Marques
- Department of Neurosciences and Behavior Sciences, Ribeirão Preto School of Medicine, University of São Paulo (HCFMRP-USP), Campus Universitário s/n Monte Alegre, Ribeirão Preto, SP, 14048-900, Brazil
| | - Iscia Teresinha Lopes-Cendes
- Department of Medical Genetics and Genomic Medicine, School of Medicine, University of Campinas - UNICAMP, Rua Tessália Vieira de Camargo, 126, Cidade Universitaria "Zeferino Vaz", Campinas, SP, 13083-887, Brazil
| | - Marcondes C França
- Department of Neurology, School of Medicine, University of Campinas - UNICAMP, Rua Tessália Vieira de Camargo, 126, Cidade Universitaria "Zeferino Vaz", Campinas, SP, 13083-887, Brazil.
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