TNNI3K and cardiomyopathy: In fact, historical studies of cardiomyopathy in B6 and D2 backcrosses have identified a QTL that was later discovered to be caused by an intronic variant in the tropin-interacting kinase gene Tnni3k (Wheeler et al. 2005; Wheeler et al. 2009), which also conferred susceptibility to viral-induced myocarditis (Wiltshire et al. 2011).