For metaxins (herein we studied MTX2, which is located at the OMM and faces the cytosolic compartment through direct interaction with its partner MTX1), we also expect high protein levels in SCA3/MJD, not just because we predict a stronger interaction with the WT ataxin-3 form compared with the expanded form, but also because the levels of SAMM50 are also reduced. This evidence concerns the gene SAMM50 and Spinocerebellar ataxia type 3.