ABGC Practice Questions (Guaranteed A+)

Under what circumstances should an infant with clinical features of Down syndrome be karyotyped? A. Only if the parents desire more children B. Only if the mother is younger than 35 years old C. Only if not all of the features of Down syndrome are present D. Only if the mother has had 3 early miscarriages E. Always correct answers E. Always What is the parental origin and stage of meiosis when most meiotic errors occur resulting in chromosomal trisomy? A. Maternal meiosis I B. Paternal meiosis I C. Maternal meiosis II D. Paternal meiosis II E. Maternal meiosis I and II are equally likely correct answers A. Maternal meiosis I A 23-year-old woman has a baby with the karyotype 47,XY,+21. Which of the following is the correct conclusion? A. This woman's risk for having another baby with a chromosome abnormality is the same as other women her age B. Either the woman or her husband probably has a Robertsonian translocation C. Either the woman or her husband probably has germ line mosaicism D. Either the woman or her husband probably carriers a balanced reciprocal translocation E. Both members of the couple probably have normal chromosomes correct answers E. Both members of the couple probably have normal chromosomes Which of the following cytogenetic results listed below indicate that the child in question has Down syndrome? A. 47,XX,+22 B. 46,XY,t(2;21)(q13;q21)pat C. 46,XY,+21,der(21;22)(q10;q10) D. 45,XX,der(14;21)(q10;q10)mat E. 46,XX.ish del(21)(q22.3q22.3)(D21S65-) correct answers C. 46,XY,+21,der(21;22)(q10;q10) T/F The karyotype of a spontaneous abortion is more likely to be abnormal than that of a stillborn infant. correct answers True T/F The most common Down syndrome karyotype involves a Robertsonian translocation between chromosomes 14 and 21 correct answers False T/F It is possible to have the Down syndrome phenotype and have 46 chromosomes. correct answers True