American Society for Clinical Pathology (ASCP) Technologist in Cytogenetics certification (ASCP CG) Practice Test

Which term best describes the karyotype notation 46,XY,der(9)(t(9;10)(q32;q12))?

1. Balanced

2. Unbalanced

3. Triploid

4. Monosomic

The correct answer is: Unbalanced

The karyotype notation 46,XY,der(9)(t(9;10)(q32;q12)) indicates that there is a derivative chromosome 9 resulting from a translocation between chromosome 9 and chromosome 10. The presence of a derivative chromosome suggests that there has been a rearrangement of genetic material. In this particular case, an unbalanced condition is implied due to the translocation. Unbalanced translocations may result in an abnormal amount of genetic material because some segments may be duplicated while others may be deleted, affecting gene dosage. The notation denotes that the genetic structure has changed, which often leads to clinical implications, such as developmental disorders or increased susceptibility to certain conditions. Balanced rearrangements, in contrast, would not lead to any gains or losses of genetic material, meaning the total amounts of chromosomal material would remain the same—this is not the case here. Triploidy and monosomy refer to specific numerical abnormalities involving whole sets or single chromosomes, which also do not apply in this situation. Thus, the karyotype notation presented best describes an unbalanced scenario.