In a population-based case-control study, including 350 cases and 724 controls, homozygote carriers of ABCB1 c.2677G>[A/T] or/and c.3435C>T risk alleles, exposed specifically to organophosphorus pesticides, had from 2 to 3.7 times higher risk to develop PD versus noncarriers (OR = 2.1, 95% CI [1.3–3.2] for homozygotes of 1 risk allele; OR = 3.7, 95% CI [2.0−7.0] for homozygotes of both risk alleles) [50]. Here, ABCB1 is linked to Parkinson disease.