SLC16A8 encodes MCT3 (monocarboxylate transporter 3), a retinal pigment epithelium (RPE)-specific proton-coupled lactate transporter that facilitates the transport of lactate and protons out of the retina 1. This transporter belongs to the SLC16 family and catalyzes proton-linked transport of monocarboxylates including L-lactate across plasma membranes 1. MCT3 plays a crucial role in maintaining pH and ion homeostasis in the outer retina by enabling transepithelial lactate transport 2. SLC16A8 has significant disease relevance, particularly in age-related macular degeneration (AMD), where multiple rare coding variants are associated with increased AMD risk 34. A splice variant that results in intron 2 retention leads to complete absence of MCT3 protein and deficient transepithelial lactate transport 2. Beyond ocular disease, SLC16A8 shows clinical significance as a prognostic biomarker in clear cell renal cell carcinoma, where overexpression correlates with poor prognosis and tumor progression through PI3K/AKT signaling pathways 5. The gene's expression levels are also significantly altered in AMD pathology independently of CFH-mediated pathways 6.