Sarcolemmal staining to C‐terminus dystrophin (Dys2, Novocastra) was present in all control muscle fibres, but no staining was seen in sections from any boys with DMD in dystrophin isoform Groups 1–3, apart from a single fibre in one section from one patient in Group 1 (Figure S2). This evidence concerns the gene DMD and Duchenne muscular dystrophy.