We hypothesized that deletion of matrilin 1, which would abolish the formation of matrilin 1/matrilin 3 heterotetramers, would also eliminate the secretion of mutant matrilin 3 into the ECM and increase the severity of chondrodysplasia in mice with the Matn3 V194D mutation. This evidence concerns the gene MATN3 and chondrodysplasia.