A common founder for amyotrophic lateral sclerosis type 8 (ALS8) in the Brazilian population

The P56S mutation in the VAPB gene causes ALS8. Eight families, comprising more than 1,500 individuals of whom about 200 are affected, are now known to carry this mutation. Seven are of Portuguese-Brazilian ancestry and one of African-Brazilian ancestry. Haplotype analysis shows a common founder for all families regardless of ancestry, with a founding event 23 generations ago (95% Cl 13-39), consistent with the Portuguese colonization of Brazil. from both families have been classified as having "spinal muscular atrophy type Finkel" (Richieri-Costa et al., 1981). Members of these families have lived in small villages in the countryside of Brazil since at least the 19th century. Recently, analysis of these and six other pedigrees totalling 1,500 individuals of whom 200 are affected, has shown that the 166C > T (P56S) mutation in the VAPB gene causes ALS8 (Nishimura et al. 2004).