ENPP1 and familial dilated cardiomyopathy: Further examples of conflicting evidence include the IVS20-11delT polymorphism of the NPPS gene, in which one study found a significant effect on DCM susceptibility [39], but two others found no significant effect [38,41], while in the IVS15-14T>C polymorphism, two studies found an effect on susceptibility [40,41], with a further study showing no significant effect [33].