Machado-Joseph disease in South Brazil: clinical and molecular characterization of kindreds

OBJECTIVE: To examine the clinical, genetic, and molecular characteristics of a group of MJD patients recently identified in the southernmost state of Brazil, and compare these data with studies from the literature. METHODS: Some 62 individuals from 35 families, mostly of Azorean ancestry, had their clinical data and their MJD1 expanded regions examined. RESULTS: The present patients had an earlier age of onset, on average, than Portuguese-Azorean cases. Their survival, proportion of types, average anticipation, proportion of affected versus non-affected siblings, neurological signs and molecular findings are similar to those observed in patients previously described. Type 1 patients with male transmission showed worse anticipations than type 1 patients with female transmission. Patients with type 1 had also larger CAG expansions than other patients. CONCLUSIONS: The Brazilian origin seemed to affect the age of onset. We also noted that there were no differences other than the neurological between types 2 or 3, since both are similar in age of onset, disease duration and length of CAG repeats. We addressed the question of maintaining or not subtypes 2 and 3 separated, among patients with genetic and geographical backgrounds like the presented patients here.