Mr. and Mrs. Annadurai have a 2 month old baby suffering from Down's syndrome. Karyotype of Mrs. Annadurai shows translocation variety of Down syndrome. Which of the following investigations will you advise to the parents before the next pregnancy?
Trisomy 21 may arise fromNon-disjunction of chromosome 21:Most common mode (95%)Risk of recurrence is 1 %Invasive prenatal diagnosis is indicatedPaternal chromosome study not neededTranslocation (or mosaicism)Paternal chromosome study is indicatedRisk of recurrence is highRef: Harrison's 18/e p510, 511, Williams 21/e p944, Ghai 5/e p478, 479
Triple test
a-fetoprotein
Karyotyping
b-human chorionic gonadotropin (hCG)
All India exam