Abstract
Phenylketonuria (PKU) is an inborn error of amino acid metabolism that is typically identified by newborn screening. With lifelong treatment consisting of dietary management, frequent laboratory monitoring, and regular metabolic clinic visits, patients with PKU can maintain good health and metabolic control. Here, we describe the case of an 8-year-old patient with PKU who has been followed by a metabolic clinic since birth. Despite responsiveness to sapropterin, this patient has had periods of poor metabolic control throughout her life due to her family's economic hardships, including limited access to transportation, housing, food, and health insurance. This case illustrates how social determinants of health may negatively affect rare disease management and potential strategies for addressing barriers to care.