Genesis of 46,XY Hydatidiform Mole

Abstract

Approximately 3 to 13 per cent of hydatidiform moles have 46,XY karyotype. In an effort to elucidate the genesis of this type, the authors made a Q-band analysis of a case with 46,XY hydatidiform mole. The patient was a 21-year-old white woman, gravida 1, para O (last menstrual period, December 15, 1980), whose uterus was found to be larger than gestational age. Human chorionic gonadotropin was 439,000 mlU/ml. Suction curettage, carried out in February, 1981, disclosed a complete hydatidiform mole, both grossly and microscopically. Tissue culture was successful, and on the 22nd day, the primary culture was harvested. Lymphocytes of the patient and her husband were also analyzed by Q-band technique. Karyotype of this hydatidiform mole revealed 46,XY, with only one of the husband's chromosomes 3 and 22 identified in duplicate. Chromosomes 3 and 22 from the hydatidiform mole were devoid of any maternal chromosomal contribution, and consequently, normal conception was ruled out. Total nondisjunction in meiosis 1 could also be ruled out by the fact that only one of the husband's chromosomes 3 and 22 was transmitted to the hydatidiform mole, which does not happen if nondisjunction takes place in all the chromosomes at the metaphase of meiosis 1 in spermatogenesis. The authors conclude that the 46,XY complete hydatidiform mole was derived from the fertilization of an ovum by two spermatozoa. No maternal chromosomal contribution was identified.