The Cerebellum

, Volume 18, Issue 6, pp 1143–1146 | Cite as

Frequency and Genetic Profile of Compound Heterozygous Friedreich’s Ataxia Patients—the Brazilian Experience

  • Thiago Mazzo Peluzzo
  • Luciana Cardoso Bonadia
  • Amanda Donatti
  • Miriam Coelho Molck
  • Laura Bannach Jardim
  • Wilson MarquesJr
  • Iscia Teresinha Lopes-Cendes
  • Marcondes C. FrançaJrEmail author
Short reports


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.


Compound heterozygous Friedreich’s ataxia FRDA mutation Genetic counseling 


Funding Information

This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brasil (CAPES)—Finance Code 001 and was supported by the Fundação de Amparo à Pesquisa do Estado de São Paulo- FAPESPs (grant no. 2013/01766-7).

Compliance with Ethical Standards

This study was approved by the Research Ethics Committee of each center. Each subject signed an informed consent before genetic testing.

Conflict of Interest

The authors declare that they have no conflict of interest.

Supplementary material

12311_2019_1055_MOESM1_ESM.docx (18 kb)
ESM 1 (DOCX 17 kb)


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Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  • Thiago Mazzo Peluzzo
    • 1
  • Luciana Cardoso Bonadia
    • 1
  • Amanda Donatti
    • 1
  • Miriam Coelho Molck
    • 1
  • Laura Bannach Jardim
    • 2
  • Wilson MarquesJr
    • 3
  • Iscia Teresinha Lopes-Cendes
    • 1
  • Marcondes C. FrançaJr
    • 4
    Email author
  1. 1.Department of Medical Genetics and Genomic Medicine, School of MedicineUniversity of Campinas – UNICAMPCampinasBrazil
  2. 2.Medical Genetics ServiceHospital de Clínicas de Porto AlegrePorto AlegreBrazil
  3. 3.Department of Neurosciences and Behavior Sciences, Ribeirão Preto School of MedicineUniversity of São Paulo (HCFMRP-USP)Ribeirão PretoBrazil
  4. 4.Department of Neurology, School of MedicineUniversity of Campinas – UNICAMPCampinasBrazil

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