FERM domains are roughly 150 amino acids in length and are found in a number of cytoskeletal-associated proteins such as Ezrin，Radixin，Moesin and 4.1 (erythrocyte membrane protein band 4.1)，where they provide a link between cytoskeletal signals and membrane dynamics. FRMD5 (FERM domain-containing protein 5) is a 570 amino acid single-pass membrane protein that contains one FERM domain and exists as two alternatively spliced isoforms. The gene encoding FRMD5 maps to human chromosome 15，which houses over 700 genes and comprises nearly 3% of the human genome. Angelman syndrome，Prader-Willi syndrome，Tay-Sachs disease and Marfan syndrome are all associated with defects in chromosome 15-localized genes.