ACADSB and 2-methylbutyryl-CoA dehydrogenase deficiency: Recently, newborn screening in Wisconsin revealed significantly elevated Isovalerylcarnitine (C5) levels in children with short/branched-chain acyl-CoA dehydrogenase deficiency, and the exon of the ACADSB gene was found to be active in this population.[51] ACADSB is enriched in the fatty acid metabolic pathway of tumor cells, and an increase in its expression level may promote the generation of acetyl-CoA.