Order a karyotype

Ana: ‘I choose to order a karyotype. Since Down’s Syndrome is an abnormality typically associated with an extra copy of chromosome 21 a karyotype should confirm if there’s any translocation or aneuploidy.’

Dr. Antoniou: ‘That’s a sound approach, Ana. Physical appearances can be misleading, especially with balanced translocations that don’t always produce overt features. Good job.’

Michael: ‘Before we finalize the test, I want to know exactly what new information the karyotype might reveal. I know it arranges chromosomes, but I’m still unclear on the specifics. How is it better than just noting physical symptoms?’

Dr. Antoniou: ‘OK Michael, let’s consider the following possibilities for what a karyotype can disclose. Which do you think are valid findings?’

A. Balanced translocations and major deletions.

B. All single-gene mutations in molecular detail.

C. Abnormal numbers of chromosomes, such as monosomy or trisomy.