NEFL and obesity due to melanocortin 4 receptor deficiency: Compared to non-frail individuals, frail participants were significantly older (mean age 54.92 vs. 41.19 years), more likely to be female (68.03% vs. 39.07%), had lower family income (39.93% vs. 21.02%), higher prevalence of hypertension (75.88% vs. 17.99%) and diabetes mellitus (62.29% vs. 15.41%), higher rates of obesity (54.22% vs. 27.65%), lower estimated glomerular filtration rate (eGFR) (mean 84.34 vs. 98.56 mL/min/1.73m2), and higher serum neurofilament light chain (sNfL) levels (mean 30.47 vs. 13.60 pg./mL) (all p < 0.01).