Chapter 29, Problem 5CAL

Ashley is a 29-year-old pregnant woman who is in the second trimester of her pregnancy. At her regular OB/GYN checkup, the doctor records the following about Ashley:

Heart rate: 92

Urinalysis: Negative for bacteria and protein in urine

Weight gain since beginning of pregnancy: 15 pounds

Blood pressure: 115/79 mm Hg

Uterine fundus height: At a midpoint between the umbilicus and the xiphoid process of the sternum

Blood glucose level: 95

5. As Ashley cares for her son, she notices some problems in his development. During one of the baby’s checkups. Ashley voices her concerns to the pediatrician. The pediatrician performs a series of assessments on the baby and orders a genetic workup. The genetic test results demonstrate that the baby has Duchenne muscular dystrophy, which is an X-linked recessive trait.

Based on your knowledge of heredity, if the baby boy has Duchenne muscular dystrophy, then what else must be true?

1. a. The baby’s father is a carrier of the Duchenne muscular dystrophy allele and passed along this trait to the baby.
2. b. Duchenne muscular dystrophy is an autosomal-dominant disorder.
3. c. Ashley is a carrier of the Duchenne muscular dystrophy allele but does not display symptoms because she has two X chromosomes, one of which is normal.
4. d. If Ashley had a baby girl (instead of a baby boy), the baby girl would be at equal risk for having Duchenne muscular dystrophy.