Relative frequency of hereditary ataxias remains unknown in many regions of Latin America. We described the relative frequency in spinocerebellar ataxias (SCA) due to (CAG)n and to (ATTCT)n expansions, as well as Friedreich ataxia (FRDA), among cases series of ataxic individuals from Peru. Among ataxic index cases from 104 families (38 of them with and 66 without autosomal dominant pattern of inheritance), we identified 22 SCA10, 8 SCA2, 3 SCA6, 2 SCA3, 2 SCA7, 1 SCA1, and 9 FRDA cases (or families). SCA10 was by far the most frequent one. Findings in SCA10 and FRDA families were of note. Affected genitors were not detected in 7 out of 22 SCA10 nuclear families; then overall maximal penetrance of SCA10 was estimated as 85%; in multiplex families, penetrance was 94%. Two out of nine FRDA cases carried only one allele with a GAA expansion. SCA10 was the most frequent hereditary ataxia in Peru. Our data suggested that ATTCT expansions at ATXN10 might not be fully penetrant and/or instability between generations might frequently cross the limits between non-penetrant and penetrant lengths. A unique distribution of inherited ataxias in Peru requires specific screening panels, considering SCA10 as first line of local diagnosis guidelines.
Bibliographical noteFunding Information:
EPM, GVF, GBB, SLS, MLSP, and LBJ were supported by the National Council for Research and Development (CNPq), Brazil. LBJ received grants from Fundo de Incentivo à Pesquisa do Hospital de Clínicas de Porto Alegre (FIPE 2006-0384) and Pesquisa para o SUS/Fundo de Apoio à Pesquisa do Rio Grande do Sul, Brazil (PPSUS-FAPERGS, PROCESS 07-00832), for performing the laboratory procedures. MCO, MIM, VM, and PM are partially supported by research funds provided by Instituto Nacional de Ciencias Neurológicas. Acknowledgments
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- CAG repeats
- Friedreich ataxia
- Inherited ataxias
- Spinocerebellar ataxia