Lack of the myotendinous junction marker col22a1 results in posture and locomotion disabilities in zebrafish

•Collagen XXII is the unique extracellular matrix marker of the myotendinous junction.•CRISPR/Cas9-mediated col22a1 gene knockout in zebrafish results in loss of the myotendinous unit integrity and dysfunctions in force transmission but with phenotypic variability•A subset of the col22a1−/− progeny displays severe phenotype accompanied with erratic movements and postural defects and dies before metamorphosis•The moderate col22a1−/− phenotype is characterized by muscle fatigue and mitochondrial adaptation to exercise in adults.•COL22A1 represents a novel candidate gene for human myopathies characterized by muscle weakness and dysfunctional force transmission.