SLC22A5 (Solute Carrier Family 22 Member 5): SLC22A5 is a protein, also known as OCTN2, that acts as a primary carnitine transporter in the body. It enables the cellular uptake of carnitine, a molecule essential for transporting fatty acids into mitochondria for energy production. This process is crucial for energy metabolism in tissues such as the heart and muscles. Mutations in the SLC22A5 gene can cause primary carnitine deficiency, a disorder characterized by muscle weakness and cardiomyopathy, underscoring its important role in metabolic health and energy regulation.