MCAT (malonyl-CoA-acyl carrier protein transacylase) catalyzes the transfer of malonyl moieties from malonyl-CoA to the phosphopantetheine arm of the mitochondrial acyl carrier protein NDUFAB1, supporting a distinct mitochondrial fatty acid biosynthetic pathway 1. Unlike the cytosolic type I fatty acid synthase complex, the mitochondrial type II system containing MCAT exhibits narrow substrate specificity and produces final products yet to be fully characterized that may play important roles in mitochondrial function 1. Additionally, MCAT functions as a mitochondrial small ribosomal subunit assembly factor, contributing to the biogenesis of mitochondrial translation machinery. The gene is associated with several disease contexts, including autosomal recessive isolated optic atrophy and hereditary optic neuropathy, though the molecular mechanisms underlying these associations remain to be elucidated. No approved drugs or established clinical interventions specifically targeting MCAT have been identified in the retrieved literature, limiting immediate therapeutic translation. The full clinical significance of MCAT dysfunction in human disease requires further investigation to bridge the gap between its well-defined enzymatic roles in mitochondrial biosynthesis and its emerging pathogenic roles in optic neuropathies.