The present invention relates to the prediction of the age-at-onset of Huntingtons disease. More specifically, it relates to the use of at least one FoxO-centered network related biallelic markers, preferably single nucleotide polymorphism (SNP) markers, in particular GSK-3β and/or TCERG1 and/or FOXO1 and/or FZD10 related biallelic markers, for prognosing the age-at-onset of symptoms of Huntingtons disease in an individual at risk of suffering from said disease. The invention also relates to lithium or a salt thereof for use at low doses in the treatment or prevention of Huntingtons disease
