Complete (classic) hydatidiform mole with 46,XY karyotype of paternal origin.

Abstract

Complete hydatidiform mole is a conceptus without an embryo, with visible general swelling of the placental villi and gross trophoblastic hyperplasia (Szulman and Surti, 1978 a and b). Such moles usually have a 46,XX karyotype, which was reported recently to be of androgenetic origin (Kajii and Ohama, 1977; Wake et al., 1978). A single X-carrying paternal haploid set 'takes over' the ovum, to which it imparts a diploid, 46,XX status by its own duplication, the other alternative being a 'take over' by a diploid XX sperm that resulted from a failure of the second meiotic division. Only a small proportion of moles are of 46,XY karyotype (3%--13%) (Wake et al., 1978; Bou6 and Bou6, 1975), and they have not yet been analyzed as to their genetic origin. They are of special interest since they must be different from the 46,XX variety in that they cannot develop by either mechanism postulated for the latter. We report here on the chromosomal origin of a complete mole with a 46,XY karyotype. A study of polymorphic chromosomal and enzyme markers of the molar and of the parental genomes revealed that the molar chromosomes are entirely of paternal origin derived from both paternal haploid sets, there being no maternal contribution. The patient is a 22-year-old Nigerian woman, recently arrived in the USA, who had a classic complete mole removed by suction curettage at 12 weeks' gestation. She subsequently developed malignant trophoblastic disease (complete with pulmonary lesions), which was successfully treated by chemotherapy, as will be published in detail elsewhere. Molar tissue was cultured as already described (Szulman and Surti, 1978a). Peripheral blood from both parents was also obtained for enzyme studies and cytogenetic analysis. At least ten metaphase spreads, from each individual were studied for polymorphic fluorescent (quinacrine dihydrochloride) markers (Table 1). Polymorphic enzyme systems were analyzed by a standard electrophoresis technique (O'Brien et al., 1979) (Table 2). Study of the polymorphic markers usually observable on chromosomes 3, 13, 14, 15, 21, and 22 revealed that such chromosome markers as were present in the mole (Table 1) were referable solely