ART4 and obesity due to melanocortin 4 receptor deficiency: Obesity was positively associated with amino acids (tyrosine, phenylalanine, isoleucine, leucine, and valine), fatty acids, glycoprotein acetyls, apolipoprotein B, and small, medium, and large low-density lipoproteins (LDL) and very low-density lipoproteins (VLDL) measures.