Chromosomal abnormalities in progressive systemic sclerosis (scleroderma) with consideration of radiation effects.

An increased frequency of cytogenetic aberrations was observed in 63 patients with progressive systemic sclerosis (PSS, scleroderma). The most striking finding was the appearance of compound aberrations (chromosomal fragments and rearrangements) in PSS patients, while none were found in the control subjects. The aberrations were nonspecific in nature. The frequency of aberrations in the PSS patients was elevated above that of other patients receiving similar diagnostic radiation exposure (less than 1 R to greater than 10 R), but showed no relation to the amount of irradiation. The dose-response relation may have been obscured by the narrow range of exposures or by a "breakage factor" newly reported in such patients. It appears that in PSS patients the increased chromosomal breakage is not associated with an elevated frequency of leukemia or other neoplasms such as has been reported to be associated with other nonspecific breakage syndromes.