PROS1 and deafness: Various genes common to the X. laevis inner ear and those of other species are associated with deafness, including structural proteins (collagen, type II, alpha 1 (COL2A1); collagen, type I, alpha 1 (COL1A1); and tectorin alpha (TECTA)), all of which have corresponding DF/Xl-PSID intensity levels above four.