With regards to limitations, in the present study, the effects of multiple covariates on QTc, including NOS1AP genotype, KCNQ1 genotype, sex, and age were assessed in the pedigree-based measured genotype association analysis, however, as the study population is relatively young (mean age 31 ± 22 years) and otherwise healthy, the model did not include additional covariates, such as obesity or drug use (medical or other), which may influence QTc. This evidence concerns the gene NOS1AP and obesity due to melanocortin 4 receptor deficiency.