ABCA5 (ATP-binding cassette, sub-family A (ABC1), member 5) is a 1,642 amino acid protein belonging to the ABC transporter superfamily and the ABCA family. The ABC1 subfamily is the only major ABC subfamily exclusive to multicellular eukaryotes. Ubiquitously expressed, with high expression in testis, skeletal muscle, kidney, liver and placenta, ABCA5 is a multi-pass membrane protein that contains two ABC transporter domains and exists as three alternatively spliced isoforms. ABCA5 exhibits membrane subcellular localization and may play a role in processing autolysosomes. Spanning 80 kb, ABCA5 contains 39 exons, with exon 2 containing the putative translation start site. ABCA5 is the first of five ABC1 family members that maps to human chromosome 17q24. ABCA5 is linked to lysosomal diseases and may play a role in tumor development and cardiomyocyte and follicular cell activities. ABCA5 might also be a specific urine marker for diagnosis of patients with high-grade prostatic intraepithelial neoplasia (HGPIN).