Schematic representation of the deduced amino acid structure of human COCH, encoding the protein cochlin, shows a predicted signal peptide (SP), followed by a domain initially designated as FCH (factor C-homology), also known as the LCCL domain, (Limulus factor C, cochlin, lung gestational protein), followed by an intervening domain, and two von Willebrand factor A-like domains (vWFA1 and vWFA2) separated by an intervening domain. Twelve mutations, (all missense except for one in-frame deletion) causing DFNA9 deafness and vestibular disorder, are indicated. The positions of all cysteine residues are shown as “C”.