<prompt> Mr. and Mrs. Annadural have a 2 month old baby suffering with downs syndrome. Karyotype of Mrs. Annadural shows translocation variety of Down syndrome. Which of the following investigation will you advise to the parents before the next pregnancy?Triple testα-fetoproteinKaryotypingβ-human chorionic gonadotropin  <response>: When a pregnant woman has a history of previous child with Down syndrome, it becomes important to know the type of chromosomal constitution, not only in that particular child but also in the parents because the risk of recurrence in future pregnancy depends on all these factors as shown in Table in Ans. 1.Karyotyping of Mrs. Annadural has already been done and a translocation variety of Downs detected. Risk of recurrence however does not depend on mothers karyotype alone, but it also depends on the fathers karyotype. Fathers karyotyping is therefore the test of choice prior to next pregnancy to determine the risk of recurrence. 