CACNB4 and idiopathic dilated cardiomyopathy: Interestingly, an intronic single nucleotide polymorphism (SNP) within CACNB4, rs150793926, was associated with idiopathic dilated cardiomyopathy in African Americans26, but this variant is not in linkage disequilibrium (LD) with rs201654520 (LD r2 27 = 0.0016 for European ancestry and LD r2 = 0.0 for African ancestry).