TRANSFERABLE CLASTOGENIC ACTIVITY IN PLASMA FROM PATIENTS WITH FANCONI-ANEMIA

The present study was conducted on 13 patients with Fanconi anemia, 25 parents and 12 siblings. The chromosomal instability characteristic o f this congenital breakage syndrome was associated with the presence o f transferable clastogenic material in the plasma, as also reported pr eviously for ataxia telangiectasia and Bloom's syndrome. While all pla sma ultrafiltrates from homozygotes had chromosome damaging properties , the clastogenic material had to be concentrated in most heterozygote s to reach detectable levels. The clastogenic effect was exerted via t he intermediacy of superoxide radicals, since it was regularly inhibit ed by superoxide dismutase (SOD). This adds further evidence for a pro oxidant state in this hereditary disease. The autosustained clastogeni c activity possibly plays a role in the progressive impairment of bloo d cell-producing bone marrow and may predispose patients to develop ca ncer and leukemia. Prophylactic use of antioxidants may be recommended , using clastogenic plasma activity as a guide.