ACADSB encodes short/branched chain acyl-CoA dehydrogenase (SBCAD), a mitochondrial enzyme that catalyzes the dehydrogenation of short and branched chain acyl-CoA derivatives, particularly (S)-2-methylbutyryl-CoA and butyryl-CoA 1. This enzyme plays a crucial role in L-isoleucine metabolism by catalyzing dehydrogenation of 2-methylbutyryl-CoA in the isoleucine catabolic pathway 1. ACADSB deficiency, also known as 2-methylbutyryl-CoA dehydrogenase deficiency, is an autosomal recessive disorder identified through newborn screening by elevated C5-carnitine levels 2. Most patients with ACADSB deficiency remain asymptomatic, though the first reported cases showed severe disease 2. Recent research reveals ACADSB's involvement in cancer biology, where reduced expression promotes colorectal cancer progression by inhibiting ferroptosis, a iron-dependent cell death mechanism 3. ACADSB overexpression enhances ferroptosis markers including lipid peroxidation and reduces glutathione levels 3. Additionally, ACADSB shows promise as a therapeutic target, with studies identifying it as a potential biomarker for small cell lung cancer 4 and acute kidney injury 5. Genetic variants in ACADSB have also been associated with hypertension in Japanese populations 6.