Loss of Matrilin 1 Does Not Exacerbate the Skeletal Phenotype in a Mouse Model of Multiple Epiphyseal Dysplasia Caused by a

Objective. Mutations in matrilin 3 can result in multiple epiphyseal dysplasia (MED), a disease charac-terized by delayed and irregular bone growth and early-onset osteoarthritis. Although intracellular retention of the majority of mutant matrilin 3 was previously ob-served in a murine model of MED caused by a Matn3 V194D mutation, some mutant protein was secreted into the extracellular matrix. Thus, it was proposed that secretion of mutant matrilin 3 may be dependent on the formation of hetero-oligomers with matrilin 1. The aim of this study was to investigate the hypothesis that deletion of matrilin 1 would abolish the formation of matrilin 1/matrilin 3 hetero-oligomers, eliminate the secretion of mutant matrilin 3, and influence disease severity