MT-ND4 and dilated cardiomyopathy: A study in 2008 involving 19 patients compared them with gender- and age-matched controls, revealing a significantly increased aortic stiffness index and diastolic aortic diameter in patients with any of the three LHON mutations (ND1, ND4, and ND5).24 However, stiffness is not a consistent finding, as one case report of a patient with the ND4 variant described a patient with neurological and dilated cardiomyopathy symptoms instead.25 These variable phenotypes may suggest different etiologies for these cardiac symptoms.