[Letters to nature]

Abstract

CYTOGENETIC studies of human lymphocytes cultured from patients and their families using known banding methods ^1–2 provide an opportunity to observe spontaneous chromosomal aberrations to identify the chromosomes involved in are arrangement and aid in interpreting the cytogenetic events leading to their formation. In our investigations of many high risk families over a 4-yr period all breaks fragments and rearrangements noted in the lymphocyte cultures were recorded along with the total number of cells counted because of previous experience in the study of X-ray induced chromosomal aber rations^4,5. The observations reported here are from 72-h cultures which may complicate their interpretation^6,7 since they are subject to the selective advantages or disadvantages of a particular chromosomal rearrangement and other factors. The many variables inherent in the analysis preclude rigorous statistical treatment of these data but a general description of the nature of occurrence may be helpful.