[Chromosome abnormalities in bone marrow cells and peripheral lymphocytes in a patient with Fanconi's anemia]

In direct preparations of bone marrow cells from an 18 years old patient with Fanconi's anaemia (FA) a low frequency of structural chromosome aberrations was observed (4% excluding gaps), while in cultured bone marrow cells (48 hours) and in cultured peripheral lymphocytes such aberrations were found to be about 3 times as many. The increase of chromosome abnormalities "in vitro" is discussed and the most recent observations on possible factors determining susceptibility to chromosome breakage in cases with FA are taken into account.