Cytogenetic studies on mid-trimester abortuses

Summary Cell cultures were set up from the skin, the kidneys, the small intestines, the gonads, and/or the lungs of 103 second trimester spontaneous abortuses. Out of these abortuses 55 gave rise to cell cultures with satisfactory growth. A normal diploid chromosome complement was found in 35 and a chromosome abnormality could be detected in 20 abortuses. X monosomy, autosomal aneuploidy, and structural aberration was observed in 5, 7 and 8 of the 20 abortuses with abnormal karyotypes, respectively. A special characteristic of the results was the high incidence of mosaics among aneuploidies and the frequent occurrence of structural anomalies. Based on these results and on those reported in the literature a pattern of chromosomal-genetic selection occurring during prenatal life was proposed.     

Origin of acrocentric trisomies in spontaneous abortuses

Summary A total of 33 spontaneous abortuses with various acrocentric trisomies were studied for the origin of the extra chromosomes using Q- and R-band polymorphisms as markers. Eleven trisomic abortuses were informative: nine trisomic abortuses (one with trisomy 13, three with trisomy 21, and five with trisomy 22 including one with a 46,XX/47,XX,+22 mosaicism) originated at maternal first meiosis; a 21-trisomic abortus resulted from an error at maternal second meiosis (or first mitosis); and a 13-trisomic abortus was of maternal first or second meiotic origin. The abortus with mosaic trisomy 22 started as a 22-trisomic zygote resulting from an error at maternal first meiosis, followed by a mitotic (in vivo or in vitro) loss of the paternally derived chromosome 22.     

Cytogenetic studies in spontaneous abortion: the Calgary experience

In a series of 493 apparently consecutive products of spontaneous abortions obtained for cytogenetic studies, tissue culture was attempted in 428 cases; chromosome analysis using the Q-banding technique was completed in 215 cases (50.2%). Abnormal karyotypes were identified in 80 cases (37.2%). Maternal tissue contamination was apparent and the actual frequency of karyotypic abnormal abortuses could be as high as 50%. Comparison of the frequency of a specific type of chromosome abnormalities with nine other series of studies showed the lowest frequency of autosomal trisomies and the highest frequency of triploidies and structural aberrations in the Calgary series. In addition, a significantly lower gestational age was observed for triploidies 69, XXX as compared to the 69, XXY.     

Anatomic and chromosomal anomalies in 639 spontaneous abortuses

Summary A total of 639 spontaneous abortuses collected in a maternity hospital were set up in culture. This sample included 565 unselected consecutive abortuses and 74 selected abortuses ascertained by morphology and/or clinical history. Among these, 339 were incomplete specimens with no recovered embryo or fetus, 110 were anatomically apparently normal and 190 were grossly abnormal. In the unselected series, 565 specimens were cultured and 402 were karyotyped; 215 (53.5%) were chromosomally abnormal. In the selected series, 74 specimens were set up in culture and 45 were karyotyped; 26 (57.7%) had an abnormal karyotype. In all, successful karyotyping was done on 447 abortuses (70%), of which 339 were studied with banding. One or more major chromosome abnormalities were detected in 241 (54%) of the karyotyped cases, 230 of which were numerical anomalies and 11 structural anomalies. Numerical anomalies included primary autosomal trisomies (31% of the total karyotyped), 45,X (10%), triploidy (6.5%), and tetraploidy (1.8%). Of the 22 types of autosomal trisomies possible, all except those for 1, 5, 17, and 19 were identified. An abortus with a 49,XX,+2,+5,+8 karyotype was detected. The excess autosomal material present in the triple trisomic abortus corresponded to 10% of the haploid autosomal complement. Of the 11 abortuses with structural abnormalities, seven were inherited while the other four were sporadic. The survival rate of 45,X conceptuses was estimated to be one in 300.     

Cytogenetic studies in 100 couples with recurrent spontaneous abortions.

The reported incidence of translocations in couples with recurrent spontaneous abortions ranges from 3% to 31% (average 9.3%). We report 100 couples in whom no reciprocal translocation carriers were ascertained.     

Cytogenetic investigation of spontaneous abortions

Summary 88 spontaneous abortions were investigated cytogenetically, 18 of them proved to have anomalies of chromosomes. Cells with aberrations were exposed to continuous cultivation. Successful prolonged cultures were grown from embryos with the following karyotypes: trisomy D, trisomy C and mosaicism (46,XX/47,XX,C+/48,XX,C+E+). It was shown that nonmosaic abnormal karyotypes were stable in the process of prolonged cultivation.

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Zusammenfassung 88 spontane Aborte wurden cytogenetisch untersucht. Bei 18 von ihnen fanden sich Chromosomenanomalien. Bei Zellen und Aberrationen wurden Langzeit-Kulturen durchgeführt. Diese Langzeit-Kulturen waren erfolgreich bei Embryonen und den folgenden Karyotypen: Trisomie D, Trisomie C und einem Mosaik (46,XX/47,XX,C+/48,XX,C+E+). Abnorme Karyotypen ohne Mosaik verhielten sich bei der Langzeit-Kultivierung stabil.

     

Congenital defect rates among spontaneous abortuses: twenty years of monitoring

A 20-year study of 1,124 spontaneously aborted embryos and fetuses found 214 (19.0%) to have a localized defect or identifiable syndrome. No clear trend of change over time was noted. The rate is compared with other studies of spontaneously aborted specimens and is approximately ten times higher than in newborns. Forty (3.6%) had neural tube defects and 30 (2.7%) had a clinically recognized chromosomal phenotype. Fifteen had Turner's phenotype, four trisomy 18, and 11 triploidy. Amniotic bands occurred in eight. Two had bilateral renal agenesis. Thirty had some form of facial cleft.     

Cytogenetic studies inEu-Sorghums

Journal of Genetics -     

Comparative analysis of chromosomal nucleolar organizing region activity in spontaneous and medical abortuses]

Comparative analysis of functional activity of silver stained nucleolar-organizing regions (NOR) activity was carried out in human fibroblasts of 70 spontaneous and 50 medical abortuses. The NOR activity was significantly higher in spontaneous abortuses compared with medical ones. This phenomenon which was observed in female, but not in male abortuses, did not depend upon the tissue origin of fibroblasts (embryonic or extraembryonic) and was due to increase of the NOR activity of the all acrocentric chromosomes to the level at which individual differences in the NOR activities among some acrocentrics were smoothed. It has been suggested that the ribosomal genes activity in different sex is likely to be differently involved in polygenic systems determining vitally important features of organism that may lead to different selection intensity in different sex resulted in deviation of the ribosomal gene copy number from the optimum. The possible role of changes in DNA methylation at the genome level in activation of ribosomal genes in spontaneous abortuses is discussed.     

Cytogenetic studies in human sperm

Summary Sperm chromosome studies were performed in seven males. One of them had a history of exposure to lysergic acid (LSD) although he was free of the drug for 1 year before the study began. Sixteen ejaculates provided a total of 555 fully analyzable sperm cells. The overall frequency of hyperhaploid sperm cells was 2% and that of structural abnormality 3.6%. The most common structural abnormality was chromosome breaks followed by small chromosome fragments of unknown origin. Three chromosome breakpoints, 10q25, 2q21, and 9q21, were involved twice in different chromosome or chromatid type aberrations. Two of these, 10q25 and 2q21, correspond to chromosomal locations known as common fragile sites.     

Karyotypes of spontaneous human abortuses and several aspects of their phenotypic presentation]

In all, 172 human spontaneous abortuses were examined: 75 cases from the 1st trimester of pregnancy (all were karyotyped), and 97 ones--from 2nd and 3rd trimesters (59 cases were karyotyped). 31 cases of chromosomal anomalies were revealed. The incidence of chromosomal anomalies among the 1st and 2--3rd trimesters of spontaneous abortuses was 40.0+/-7.5 and 1.0+1.0%, resp. The general incidence of chromosomal anomalies among this series of spontaneous abortuses was equal to 18.0+/-2.9%. The question of phenotypical manifestations of chromosomal aberrations in spontaneous abortuses is discussed. The influence of gene structure of aberrant chromosomes on phenotypes of abortuses is supposed.