[Triploidy as a cause of midtrimester gestosis(author's transl)]

The parent-of-origin effect of 10q22 in pre-eclamptic females coincides with two regions clustered for genes with down-regulated expression in androgenetic placentas

By affected sib-pair linkage analysis of 24 families with pre-eclampsia, we confirm a susceptibility locus on chromosome 10q22.1 in Dutch females: a multipoint non-parametric linkage score of 3.6 near marker D10S1432 was obtained. Haplotype analysis showed a parent-of-origin effect: maximal allele sharing in the affected sibs was found for maternally derived alleles in all families, but not for the paternally derived alleles. As matrilineal inheritance suggests the presence of maternally expressed imprinted genes, while imprinting operates predominantly in (extra)embryonic tissues, all genes (n=132) known on 10q22 between GATA121A08 and D10S580 were screened for seven sequence-related features associated with imprinting and subsequently tested for expression in first trimester placenta. Placental expression of genes selected in this way (n=55) was compared with expression in androgenetic placentas of identical gestational age. Two regions on 10q22 were identified with developmentally co-repressed genes with non-random chromosomal distribution. Interestingly, these two clusters, near CTNNA3 and KCNMA1 and each containing five genes with down-regulated expression in androgenetic placentas, coincided with the regions with maximal maternal allele sharing seen in the pre-eclamptic sisters. Our linkage and expression data are compatible with the concept that pre-eclampsia involves maternally expressed imprinted genes that operate in the first trimester placenta.

Cyclopia and cebocephaly in two newborn infants with unbalanced segregation of a familial translocation rcp (1;7)(q32;q34)

This is a report of a family with a balanced reciprocal translocation, rcp (1;7)(q32;q34). Among pregnancies from translocation carriers, there were several miscarriages, and two unbalanced offspring with dup(1q32----qter) and del (7q34----qter) who died perinatally. One was a male cyclops with additional brain malformations and hydronephrosis, the other was a cebocephalic female with multiple additional malformations of heart, kidneys, and skeleton. In both pregnancies, the brain and renal anomalies were detected prenatally by ultrasound, in the cyclops during the 32nd and in the cebocephalic fetus during the 28th week of gestation.

Genetic studies on hydatidiform moles

Using an historical approach, this article describes how genetic studies have elucidated the two entities into which the syndrome of hydatidiform mole can now be divided. Partial moles are triploid, have a maternal chromosomal set, and are associated with the presence of a fetus. Complete moles lack a fetus and are always diploid and androgenetic in origin, having two sets of paternal chromosomes. They are most often XX and homozygous, the most likely origin being by duplication of a haploid sperm. About 4% of complete moles have been shown to by XY and heterozygous, the most likely origin being by dispermy. The frequency of partial and complete mole observed depends on the method of ascertainment. Among spontaneous abortions, partial moles are more common than complete moles, but among cases having an elective termination of pregnancy because of a prior diagnosis of hydatidiform mole, complete mole is the more common. Patients with either type of mole may require treatment for persistent trophoblastic activity. More prospective studies of cases in which the type of mole has been confirmed by genetic studies are required in order to find out whether (a) patients with complete moles are more likely than those with partial moles to require treatment for persistence of trophoblastic activity after evacuation; and (b) heterozygous complete moles have a different prognosis from the point of view of malignant sequelae than homozygous complete moles.

Morphologic anomalies in triploid liveborn fetuses

Analysis of the morphologic features of 43 complete and 11 mosaic triploid infants delivered at or after 22 weeks of gestation revealed, in addition to well-delineated gross features, a number of new or previously little emphasized histopathologic features. These included testicular Leydig cell hyperplasia, increased levels of hematopoiesis, and ovarian, adrenal, and pulmonary hypoplasia. Some of these findings appeared to be linked to partial hydatidiform mole replacing the normal placenta, which was present in about 70 per cent of the triploid cases. It is important to recognize the breadth of the triploidy spectrum, which ranges from near normalcy to multisystem involvement, and to pay special attention to the placenta. The importance of correct morphologic diagnosis of triploidy is stressed in view of the fact that its occurrence apparently does not prejudice the future reproductive performance of the parents.

Human triploidy: relationship between parental origin of the additional haploid complement and development of partial hydatidiform mole

One hundred and six triploids were ascertained during a study of 1500 consecutive spontaneous abortions. The mechanism of origin of the additional haploid complement was investigated by comparing parental and foetal cytogenetic heteromorphisms and a histopathological examination of each triploid was done in a subsequent blind study. The mechanism of origin of the additional haploid complement was found to be highly correlated with the development of partial hydatidiform mole and with gestational age. All 51 paternally derived triploids in which a pathologic diagnosis could be made were partial moles, whereas only 3 of 15 maternally derived triploids on which a diagnosis could be made were molar. The mean gestational age of the paternally derived triploids was 122 days while that of the maternally derived triploids was only 74 days. It was suggested that the development of partial mole was primarily associated with the presence of two paternal haploid chromosome complements, the association with relatively long gestational ages being a secondary one consequent upon retention of the molar placentae for many weeks after foetal demise.

Genetic studies on hydatidiform moles. I. The origin of partial moles

A study was designed to investigate the genetic origin of hydatidiform moles. Fifty-nine specimens were obtained and, on a histological basis, separated into two entities: complete and partial. The study of the genetic origin of the 15 partial moles, using cytogenetic and biochemical markers, is described. All the partial moles examined cytogenetically were triploid. One had 71 chromosomes. The sex chromosome complements of seven cases were six XXY and one XXX. Origin by dispermy was possible in seven cases and was proven in four. With the use of biochemical markers a maternal contribution was identified in three cases, and the isoenzyme pattern suggested a trisomic state for at least one locus in four cases. The mechanism of origin of partial moles was compared with spontaneously aborted and liveborn triploids. All the patients were followed up for at least 9 months, and none required treatment for persistent trophoblastic activity.