A 43-year-old woman visits her obstetrician for her scheduled
check-up at 20 weeks’ gestation. Her obstetrician recommends
that she have a series of screening tests. One of these tests
shows an elevated serum a-fetoprotein level. Which of the
following is most likely responsible for this result?
(A) Bilateral renal agenesis
(B) Failure of the ductus arteriosus to close
(C) Inadequate folic acid intake
(D) Inheritance of a recessive disorder
(E) Nondisjunction occurring during meiosis…
