Having confirmed that the ACTN2 and Z1Z2 Affimers outperform antibodies in labelling these proteins within the Z-disc, we then used these 2 Affimers and one additional Affimer isolated to ZASP to stain the Z-discs in control samples (age, sex matched) and in two heart samples from two different DCM patients (DCM1 and DCM2) sharing the same A-band titin mutation. Here, ACTN2 is linked to familial dilated cardiomyopathy.