We have shown that (i) KLK6 and CAPN1 are reduced in post-mortem brain tissue in DLB, in regions of cerebral cortex that show most marked accumulation of α-syn, (ii) the amount of α-syn in these regions correlates inversely with KLK6 and CAPN1 level and activity, (iii) KLK6 and CAPN1 partially co-localised with α-syn in SH-SY5Y cells overexpressing wild-type α-syn, and (iv) the level of α-syn within these cells increases after down-regulation of KLK6 and CAPN1 by siRNA knock-down. The gene discussed is KLK6; the disease is Lewy body dementia.