Cytogenetic abnormalities in a patient with hypercalcemia and papillary thyroid carcinoma.

Cytogenetic examinations on multiple peripheral blood cultures of a patient with papillary thyroid carcinoma and hypercalcemia revealed with following features: (1) The average frequency of cells with aberrations was 11.6%, considerably higher than in controls. Among metaphases with chromosomal abnormalities, 4.5% has chromosome-type aberrations. (2) One homolog of chromosome 11 showed a fragile site in the proximal end of the long arm, and in three metaphases the segment distal to the fragile site showed "branched morphology." (3) The rate of sister chromatid exchanges was within normal limits (8.78/metaphase). (4) The patient's two sons showed 7.0% and 5.0% abnormal metaphases, in the high normal range.