In MSUD patients, CACNA2D2, and MECP2 E1 and E2 isoforms mRNAs were significantly downregulated (p = 0.007; p = 0.027; p = 0.001 respectively), while THBS1 mRNA was upregulated (p = 0.047) with respect to controls. This evidence concerns the gene MECP2 and maple syrup urine disease.