PLN and obesity due to melanocortin 4 receptor deficiency: We excluded known confounders of a low voltage ECG including obesity (body weight to tibia length ratio 1.14 ± 0.05 vs. 1.46 ± 0.02, P value = 0.0012, of PLN R14Δ/Δ vs. wild-type, Supplementary Fig. 9), and cardiac effusion which was not observed at sacrifice in PLN R14Δ/Δ mice.