We failed to detect a CAV3 mutation, but instead found a novel homozygous mutation in PTRF. Our findings suggest that, in the presence of myopathy associated with spontaneous or percussion-induced muscle contractions (rippling or mounding), mildly reduced caveolin 3 expression and no CAV3 mutation, the PTRF gene should be investigated, particularly in young patients in whom lipodystrophy may be difficult to ascertain. The gene discussed is CAVIN1; the disease is myopathy.