Phytanoyl-CoA hydroxylase is an enzyme that plays a crucial role in the metabolism of certain fatty acids, particularly phytanic acid. It is involved in the breakdown of phytanoyl-CoA, converting it into pristanic acid through a hydroxylation reaction. This process is essential for the proper utilization of dietary fats and the maintenance of cellular functions. Deficiencies in phytanoyl-CoA hydroxylase can lead to a rare genetic disorder known as Refsum disease. This condition is characterized by the accumulation of phytanic acid in the body, resulting in various health issues, including vision problems, hearing loss, and neurological symptoms. Understanding this enzyme is vital for diagnosing and managing related metabolic disorders.