NTN1 and obesity due to melanocortin 4 receptor deficiency: In normoalbuminuric obese children and adolescents without significant metabolic disorders, serum t-CAF may be a new biomarker for the early detection of renal dysfunction, and urinary netrin-1, α-GST, π-GST, and calprotectin may be better indicators for the detection of early tubular damage, independent of the severity of obesity.