Relevant clinical and genetic findings of patients
| Patient | Phenotype | Onset age* | Relevant clinical findings | Loss of ambulation* | Muscle biopsy findings† | Genomic variant‡ | mRNA alteration‡ |
| P1 | BMD | Early childhood | Clumsy walking and muscle weakness | No (midle childhood) | Myopathic changes with partial deficiency of DYS-3 staining | g.32584731A>G | PE15 |
| P2 | BMD | Early adolescence | Muscle weakness | Yes (adult) | Numerous atrophic and hypertrophic fibres with size variability and internal nuclei Overexpression of utrophin and almost absent expression of DYS3 | g.32371864A>C | PE37 |
| P3 | BMD | Middle childhood | HyperCKemia | No (early adolescence) | Conserved skeletal muscle architecture, with occasional internalised nuclei Reduction of DYS-2 staining in WB | – | Exon nine skipping |
| P4 | DMD | Early childhood | Difficulties in climbing stairs, difficulties with fine and gross motor skills, mild pseudohypertrophy of gastrocnemius, biceps, triceps and paraspinal muscles | No (early childhood) | Reduction of DYS-1 expression and absence of DYS-2 and DYS-3 expression Reduction of sarcoglycan expression | g.31279418T>C | PE62 |
| P5 | BMD | Adult | HyperCKemia, calf hypertrophy, muscle cramps and myalgia after exercise | No (adult) | Mild dystrophic pattern with alterations in dystrophin staining | – | Exon 71 and 78 skipping |
| P6 | BMD/DMD | Early childhood | Down syndrome, with frequent falls and proximal muscle weakness | Yes (early adolescence) | Dystrophic pattern with reduced DYS-2 and DYS-3 staining Partial alteration of dystrophin WB | g.32873008_32873015delins (CCA;chr8:g.16346710_16422443) | Cryptic exon (chr8) |
| P7 | BMD | Midle childhood | HyperCKemia and rhabdomyolysis | No (midle childhood) | Mild dystrophic pattern with reduced DYS-2 and DYS-3 staining Almost absence of DYS-2 in WB | – | Exon 71 skipping |
* Early childhood, 2–5 years; middle childhood, 6–11 years; early adolescence, 12–18 years; late adolescence, 19–21 years.
†Monoclonal antibodies detecting the rod domain (DYS1), C-terminal domain (DYS2) and N-terminal (DYS3) domain of dystrophin.
‡Variant description based on NC_000023.11, NC_000008.10 and NM_004006.2.
BMD, Becker muscular dystrophy; CK, creatine kinase; DMD, Duchenne muscular dystrophy; PE, Pseudoexon; WB, western blot.