SNCA and Alzheimer disease: For instance, a study that assessed mutations in established causal genes for PD and AD among 99 patients with DLB found evidence of a contribution of these genetic factors only to a small percentage of subjects.[57] In another association study of a much larger cohort of DLB cases and controls assessing 54 genomic regions previously implicated in PD or AD, Bras et al.[58] confirmed the association of the APOE locus with DLB and found that the SNCA and SCARB2 loci are also associated with DLB, although with a different profile than the associations reported in PD.