OBJECTIVES: Frequency and distribution of dominant ataxias caused by dynamic mutations may vary in different populations, which has been explained on the basis of relative frequency of predisposing normal alleles. The aim of the study was to evaluate the occurrence of spinocerebellar ataxias (SCAs) and dentatorubral-pallidoluysian atrophy (DRPLA) in Finland, and to investigate the role of predisposing normal alleles in a genetically homogenous population. MATERIAL AND METHODS: Mutation analyses for SCA1, 2, 3, 6, 7, 8, 10, 12, 17, and DRPLA and frataxin genes were performed for 251 unrelated Finnish patients who presented with progressive ataxia disorder. RESULTS: Expansions of SCA1, SCA2, SCA6, SCA7, SCA8, and SCA17 genes were detected in 2, 1, 1, 7, 22, and 1 patients, respectively. Altogether, 39 and 7% of dominant and sporadic SCA patients, respectively, harboured expansions at some of the investigated loci. Normal variation, collected from 477 to 502 chromosomes at each disease loci, revealed that Finns were different from the Japanese but largely similar to other Caucasians. CONCLUSIONS: Lack of SCA3 and excess of SCA8 are characteristic to the Finnish population. Homozygosity for the SCA8 expansion increases penetrance. Frequencies of large normal alleles at the SCA loci predict poorly prevalence of the respective diseases in Finland. Prioritization in DNA testing, based on ethnic origin and geographical location, is recommendable in Finland, and analogous approach may be applied to other countries as well.
OBJECTIVES: Frequency and distribution of dominant ataxias caused by dynamic mutations may vary in different populations, which has been explained on the basis of relative frequency of predisposing normal alleles. The aim of the study was to evaluate the occurrence of spinocerebellar ataxias (SCAs) and dentatorubral-pallidoluysian atrophy (DRPLA) in Finland, and to investigate the role of predisposing normal alleles in a genetically homogenous population. MATERIAL AND METHODS: Mutation analyses for SCA1, 2, 3, 6, 7, 8, 10, 12, 17, and DRPLA and frataxin genes were performed for 251 unrelated Finnish patients who presented with progressive ataxia disorder. RESULTS: Expansions of SCA1, SCA2, SCA6, SCA7, SCA8, and SCA17 genes were detected in 2, 1, 1, 7, 22, and 1 patients, respectively. Altogether, 39 and 7% of dominant and sporadic SCA patients, respectively, harboured expansions at some of the investigated loci. Normal variation, collected from 477 to 502 chromosomes at each disease loci, revealed that Finns were different from the Japanese but largely similar to other Caucasians. CONCLUSIONS: Lack of SCA3 and excess of SCA8 are characteristic to the Finnish population. Homozygosity for the SCA8 expansion increases penetrance. Frequencies of large normal alleles at the SCA loci predict poorly prevalence of the respective diseases in Finland. Prioritization in DNA testing, based on ethnic origin and geographical location, is recommendable in Finland, and analogous approach may be applied to other countries as well.
Authors: Anna H Hakonen; Silja Heiskanen; Vesa Juvonen; Ilse Lappalainen; Petri T Luoma; Maria Rantamaki; Gert Van Goethem; Ann Lofgren; Peter Hackman; Anders Paetau; Seppo Kaakkola; Kari Majamaa; Teppo Varilo; Bjarne Udd; Helena Kaariainen; Laurence A Bindoff; Anu Suomalainen Journal: Am J Hum Genet Date: 2005-07-27 Impact factor: 11.025
Authors: Raphael Machado de Castilhos; Gabriel Vasata Furtado; Tailise Conte Gheno; Paola Schaeffer; Aline Russo; Orlando Barsottini; José Luiz Pedroso; Diego Z Salarini; Fernando Regla Vargas; Maria Angélica de Faria Domingues de Lima; Clécio Godeiro; Luiz Carlos Santana-da-Silva; Maria Betânia Pereira Toralles; Silvana Santos; Hélio van der Linden; Hector Yuri Wanderley; Paula Frassineti Vanconcelos de Medeiros; Eliana Ternes Pereira; Erlane Ribeiro; Maria Luiza Saraiva-Pereira; Laura Bannach Jardim Journal: Cerebellum Date: 2014-02 Impact factor: 3.847