Here we present five subjects from three novel SCA21 families from different parts of the world (including a novel c.196G > A, p.G66R TMEM240 variant from Colombia), demonstrating that, in addition to cerebellar ataxia, not only hypokinetic features (hypomimia, bradykinesia), but also hyperkinetic movement disorders (poly-mini-myoclonus, proximal myoclonus) are a recurrent part of the phenotypic spectrum of SCA21.