A third patient who had early onset PD (onset age fourth decade) due to a compound heterozygous mutation in PARK2 (p.G430D/pR275W) also had the p.R98W TREM2 possible risk factor for AD,16 but displayed no evidence of any amyloid deposition at postmortem (see online supplementary table 8,9). The gene discussed is PRKN; the disease is Parkinson disease.