SNCA and Parkinson disease: Strikingly, TMEM175 and SNCA also modulate age at onset in Parkinson’s disease.12 On the other hand, there are distinct loci for dementia with Lewy bodies compared with Parkinson’s disease encompassing different genes (e.g. APOE and BIN1 for dementia with Lewy bodies), and, in some cases, distinct association signals at the same locus.