Literature review assessing genetic risk of dementia due to APOE4 or MAPT in Parkinson's disease, performed on the 13th February 2018. All studies had to fulfil three a priori inclusion criteria: 1) Case control studies using clinically diagnosed or pathologically confirmed PD and PDD. 2) Time between motor diagnosis and experimental assessment could be defined or estimated. 3) Genotype information supplied, allowing the odds ratio (OR) and confidence intervals (CI) to be calculated that aligned with the genotype categories used in this work. For MAPT, a PubMed search for the term “MAPT Parkinson’s dementia” identified 105 potential matches, of which 9 met the inclusion criteria. For APOE4, a PubMed search for the term “APOE Parkinson’s dementia” identified 188 potential matches, of which 19 met the inclusion criteria. Note, the review includes several publications arising from the CamPaIGN cohort; As we were interested in genetic risk as a function of time from diagnosis, we included each unique study time-point.