CCDC102B (coiled-coil domain containing 102B), also known as AN, ACY1L or HsT1731, is a 513 amino acid protein that exists as three alternatively spliced isoforms. Widely expressed and found in multiple CNV (copy-number variant) regions, CCDC102B contains the deletion breakpoint of a maternally inherited deletion, which is 2.7 Mb in size, and maps to human chromosome 18q22.1. CCDC102B may play a role in the pathogenesis of diaphragmatic hernia, microphthalmia, colorectal carcinoma and schizophrenia. Encoding over 300 genes, chromosome 18 contains about 76 million bases. Translocation between chromosomes 18 and 14 is the most common translocation in cancers and occurs in follicular lymphomas. Niemann-Pick disease, hereditary hemorrhagic telangiectasia and erythropoietic protoporphyria are associated with chromosome 18.