Inclusion Criteria: * Possess 1 homozygous or 2 heterozygous pathogenic and/or likely pathogenic DYSF Deoxyribonucleic acid (DNA) gene mutations as documented prior to screening visits. * Participants must be ambulatory per protocol specified criteria. * Ability to cooperate with motor assessment testing. * Has accessible and intact lower and upper extremity musculature for biopsy. * Have adeno-associated virus rhesus serotype 74 (rAAVrh74) antibody titers \< 1:400 (that is, not elevated) as determined by enzyme-linked immunosorbent assay (ELISA). Exclusion Criteria: * Exposure to gene therapy, investigational medication, or other protocol-specified treatment within the protocol specified time limits. * Abnormality in protocol-specified diagnostic evaluations or laboratory tests. * Presence of any other clinically significant illness, medical condition, or requirement for chronic drug treatment that in the opinion of the Investigator creates unnecessary risk for gene transfer. Note: Other inclusion or exclusion criteria could apply.