The Parents of a Child Who Is Mosaic for Trisomy

The parents of a child who is mosaic for trisomy 21 ask if there is a way to identify the proportion of their child's cells that are affected.What is the nurse's best answer?

A) "There are several simple tests to determine the proportion of mosaic cells."
B) "The only reliable test is very expensive."
C) "Testing can be done in Europe,but not in the United States."
D) "Reliable testing can only be done on autopsy."