CGREF1 (cell growth regulator with EF-hand domain 1), also known as CGR11, is a 301 amino acid secreted protein that contains two highly conserved calcium binding EF-hand domains, which are required for mediating cell-cell adhesion. Induced by p53, CGREF1 is able to inhibit cell growth in various cell lines. CGREF1 is encoded by a gene located on 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, Alstrωm syndrome, is caused by mutations in the ALMS1 gene, which maps to chromosome 2.