Absence of chromosomal instability in one kindred with multiple endocrine neoplasia type 2A.

PHA-stimulated peripheral blood lymphocyte cultures were established from four individuals with multiple endocrine neoplasia type 2A, four control spouses and 13 at-risk offspring. No increase in the frequency of chromosomal aberrations was observed in the cultures of the affected individuals when compared with the frequency of chromosomal aberrations observed in the cultures established from the control spouses. No increased chromosomal instability was noted in the cultures of at-risk individuals. These results are in contradiction with previous reports of increased chromosomal instability among individuals with the multiple endocrine neoplasia type 2A.