Question

A 24-year-old woman is diagnosed as having a complete molar pregnancy with enlargement of the chorionic villi and absence of an embryo. Cytogenetic analysis of the products of conception revealed a 46,XX karyotype. The molar pregnancy was caused by which one of the following?

(A) preeclampsia
(B) two haploid sets of paternal chromosomes
(C) trophoblastic neoplasia
(D) elevated hCG levels
(E) enlarged uterus

Answer 1

A complete molar pregnancy in a woman with a 46,XX karyotype is most likely caused by two haploid sets of paternal chromosomes.

Step-by-step explanation:

The complete molar pregnancy diagnosed in a 24-year-old woman with enlargement of the chorionic villi and absence of an embryo and a 46,XX karyotype was most likely caused by two haploid sets of paternal chromosomes. In a normal pregnancy, fertilization of an oocyte by a sperm results in a zygote with a combination of maternal and paternal chromosomes, producing a diploid zygote. However, in some cases, such as complete molar pregnancies, the oocyte may become fertilized by two sperm or by one sperm with duplicated chromosomes, leading to a diploid zygote containing only paternal genetic material. This results in the abnormal growth of trophoblasts and the absence of an embryo.