RecruitingPhase 2Drug trialStudy of Sodium Phenylbutyrate (ACER-001) for the Treatment of Pediatric and Adults Patients With Medium Chain Acyl-CoA Dehydrogenase Deficiency (MCADD)This is a medical research study to test a medication in patients 4 years of age and older with a disease called medium-chain acyl-CoA dehydrogenase deficiency (MCADD) caused by the common ACADM c.985 A\>G (K304E) mutation. The medication is sodium phenylbutyrate (ACER-001), which is currently FDA approved for the treatment of Urea Cyle Disorders. Previous research suggests that sodium phenylbutyrate may also be effective in the treatment MCADD. This study will investigate the safety and efficacy (how well it works) of sodium phenylbutyrate in patients with MCADD.