Which complete hydatidiform mole genetic characteristic distinguishes it from a partial mole?
- A Complete mole is usually diploid (46,XX or 46,XY), entirely androgenetic (all paternal chromosomes), with no maternal nuclear DNA; partial mole is triploid (69,XXX or 69,XXY) with both maternal and paternal chromosomes ✓
- B Complete mole is triploid; partial mole is diploid
- C Complete mole has focal trophoblastic proliferation; partial mole has diffuse trophoblastic proliferation
- D Complete mole always has a fetus present; partial mole lacks a fetus
Correct answer: A. Complete mole is usually diploid (46,XX or 46,XY), entirely androgenetic (all paternal chromosomes), with no maternal nuclear DNA; partial mole is triploid (69,XXX or 69,XXY) with both maternal and paternal chromosomes
Explanation
Complete hydatidiform mole is typically diploid 46,XX (rarely 46,XY), entirely of paternal (androgenetic) origin — arising from fertilization of an empty egg by one sperm that duplicates or two sperm. There is diffuse trophoblastic hyperplasia and no fetal or embryonic tissue. Partial mole is triploid (69,XXX, 69,XXY, or 69,XYY), has maternal and paternal genetic contributions, shows only focal trophoblastic hyperplasia, and may have identifiable fetal/embryonic tissue. Risk of GTN is 15–20% for complete mole vs 0.5–5% for partial mole.
Reference: Williams Obstetrics, 26th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.