COX7A2 and dilated cardiomyopathy: In another mouse study, Cox7a1 KO mice were viable and presented a dilated cardiomyopathy at 6 weeks of age with the Cox7a1 KO mice incorporating more of the “liver-type” isoform of Cox7a2 into the cardiac Cox holoenzyme, translating in higher tissue ATP levels (Huttemann et al. 2012).