Hyaluronidase-1, also known as HYAL1 or LUCA1, is an enzyme that in humans is encoded by the HYAL1 gene. The gene is one of several related genes in a region of chromosome 3p21.3 associated with tumor suppression. This gene encodes a lysosomal hyaluronidase. Hyaluronidases intracellularly degrade hyaluronan, one of the major glycosaminoglycans of the extracellular matrix. Hyaluronan is though to be involved in cell proliferation, migration and differentiation. This enzyme is active at an acidic pH and is the major hyaluronidase in plasma. Mutations in this gene are associated with mucopolysaccharidosis type IX, or hyaluronidase deficiency.