Distribution of dominant ataxias and Friedreich's ataxia in the Spanish population

BACKGROUND: To establish the distribution of the different forms of dominan t ataxias and Friedreich ataxia in Spanish population. PATIENTS AND METHODS: We have performed a molecular study in 121 patients p resenting ataxia as the first sign of neurodegenerative disease. In these p atients, we have performed a molecular study of SCA 1, SCA 2, SCA 3, SCA 6, SCA 7, SCA 8, DRPLA, alpha-TTP (tocopherol transfer protein) and Friedreic h's ataxia genes. RESULTS: The study showed that the Friedreich ataxia is the most frequent f orm representing 34.4% of the total of the hereditary ataxias, One patient presented mutation in alpha-TTP gene. Among the dominant forms SCA 3 was th e most frequent (27.3%) followed by SCA 7 (16%), SCA 6 (9%) and SCA 2 (4.5% ). We have not found mutations in SCA 1 and DRPLA genes. Two of 60 apparent ly sporadic cases presented mutations in the SCA 6 and SCA 8. CONCLUSIONS: The genetic analysis is the principal method to distinguish th e different clinic forms of ataxia, We have not found mutations in 41.2% of dominant forms and in 43.3% of recessive forms. These results suggest the existence of new candidates genes.