MMUT and neoplasm: Last, “beiging” of subcutaneous adipose tissue in MMA was characterized by the markedly increased 18F-FDG uptake in subcutaneous adipose depots of a 13-year-old mut0 MMA Hispanic girl (compound heterozygous variants in MMUT: c.1106G>A; p.Arg369His and c.1196_1197del; p.Val399GlufsTer24), who underwent a radiolabeled glucose (18F-FDG) PET study to rule out an ectopic parathyroid hormone–secreting tumor suspected because of hypercalcemia (Figure 5D and Supplemental Figure 4).