African-specific variability in the acetylcholine muscarinic receptor M4: association with cocaine and heroin addiction.
Levran O, Randesi M, Peles E, Correa da Rosa J, Ott J, Rotrosen J, Adelson M, Kreek MJ. Pharmacogenomics. 2016 Jun; 17(9):995-1003. Epub 2016 Jun 7.