ABCA5 is an ATP-binding cassette transporter that functions primarily as a cholesterol efflux pump in multiple cell types. In macrophages, ABCA5 serves as a cholesterol efflux transporter responsible for APOAI/high-density lipoprotein formation and participates in reverse cholesterol transport, particularly under high cholesterol conditions where it compensates for downregulated ABCA1 1. The protein exhibits a unique conformation that favors cholesterol loading onto HDL particles for efficient reverse cholesterol transport 1. ABCA5 is expressed across various tissues including brain, liver, pancreas, and testis, with particularly high expression in neurons where it can stimulate cholesterol efflux 23. The transporter localizes to lysosomes and late endosomes, playing a role in autophagosome processing and endolysosomal cholesterol regulation 45. Clinically, ABCA5 has significant disease relevance: mutations cause congenital generalized hypertrichosis terminalis through impaired lysosome function and autophagosome accumulation 4. In Alzheimer's disease, ABCA5 expression is elevated in hippocampus and reduces amyloid-Ξ² peptide production without affecting AΞ²PP expression 3. Additionally, ABCA5 upregulation has been associated with chemotherapy resistance in cancer and identified as a potential biomarker in osteoarthritis progression 67.