MYO7A and Down syndrome: A total of 13 genes have been previously associated with US, of which CDH23, PCDH15, USH1G, MYO7A, USH1C, and CIB2 affect Usher syndrome type 1B (USH1B)4\.4 The cell is supported by a framework of cytoskeleton that is made up of microtubules (tubulin), intermediate filaments, and microfilaments (actin).