HYAL1 and Hyaluronidase deficiency: Major clinical developmental phenotypes result from mutations in hyaluronidases such as mucopolysaccharidosis type IX from Hyal1 (Natowicz et al., 1996), bone defects, and cardiopulmonary dysfunction from loss of Hyal2 (Jadin et al., 2008; Chowdhury et al., 2013).