A recent study which investigated the role of all four common GST polymorphisms in the susceptibility to progressive myoclonus epilepsy (PME) showed the potential effect of the GSTT1-null genotype on disease development that was even more potentiated in the carriers of combined GSTA1*CC/GSTT1-null genotype who exhibited the greatest risk of developing PME (54). Here, GSTA1 is linked to progressive myoclonus epilepsy.