TGFB1 and hypoplastic left heart syndrome: This observation is in contrast to our previous study showing that activity of TGF-β signaling pathways in HLHS-RV was most similar to Control-LV.[16] Despite the unique genetic profiles in HLHS-RV vs. Control-LV and Control-RV, differentially expressed genes associated with ‘oxidative phosphorylation’ were similarly affected in HLHS-RV when compared to each of the control groups (Table 6).