NOS1AP and diabetes mellitus: Apart from the genetic polymorphisms involving the methadone metabolic pathway, common variants in the nitric oxide synthase 1 adaptor protein gene (NOS1AP) have been implicated in QTc interval prolongation and risk of sudden cardiac death both in general populations and in patients with diabetes, coronary artery disease, and drug-induced long QT syndrome [15,16,17,18,19,20,21].