“…These focal lesions, which resemble the fibromuscular lesions in atherosclerosis might be a result of monoclonal proliferation of the smooth muscle cell. This is one among other theories which could explain the development of the atherosclerotic plaque (Bjorkerud 1979, McGill 1977, Ross 1980, Wissler 1980. Evidence for a monoclonal origin of the human atherosclerotic plaque, fibromuscular lesions and fatty streaks, seem well established by studies on the X-linked glucose -6phosphate dehydrogenase (Benditr and Bendirt , Benditr 1974, Pearson er al.…”