APLF is a 511 amino acid protein that contains one FHA doman and two C2H2type zinc fingers. Localized to both the nucleus and the cytoplasm, APLF interacts with XRCC1, XRCC4 and Ku-86 and, via these interactions, is involved in single-strand and double-strand DNA break repair. APLF is subject to post-translational phosphorylation in response to DNA breaks. The gene encoding APLF maps to human chromosome 2, which houses over 1,400 genes and comprises nearly 8% of the human genome. Harlequin icthyosis, a rare and morbid skin deformity, is associated with mutations in the ABCA12 gene, while the lipid metabolic disorder sitosterolemia is associated with defects in the ABCG5 and ABCG8 genes. Additionally, an extremely rare recessive genetic disorder, is caused by mutations in the ALMS1 gene, which maps to chromosome 2.