- Resolution of a mispaired secondary structure intermediate could account for a novel micro-insertion/deletion (387 insA/del 8 bp) in the PYGM gene causing McArdle's disease. Martín, M.A., Rubio, J.C., García, A., Fernández, M.A., Campos, Y., Krawczak, M., Cooper, D.N., Arenas, J. Clin. Genet. (2001)