Role of chromosome aberrations in recurrent abortion: A study of 269 balanced translocations

Abstract

We have studied a sample of 5,445 couples in which the woman was ascertained to have had two or more spontaneous abortions: 396 from our Cytogenetics Unit (present series) and 5,049 from the literature (literature series). In approximately 5% of these couples one of the members was a carrier of a balanced translocation, either reciprocal (2/3 of cases) or Robertsonian (1/3). In 1% of the couples there were other chromosome anomalies, mostly gonosomal aneuploidies or mosaicisms. A pericentric inversion of the heterochromatic region of chromosome 9 was present in 3% of the couples of the present series and in 1% of the literature series. The number of female carriers exceeded significantly that of males. The probability for one member of the couple to be a carrier increased with the number of abortions at the time of ascertainment, but it does not seem modified by the concomitant presence of term pregnancies. The analysis of the cytogenetic findings in 80 cases of Robertsonian and 156 cases of reciprocal translocations suggests that some chromosomes are preferentially involved, and that in reciprocal translocations the breakpoints are not distributed at random on the chromosome arms. There is an excess of breakpoints on chromosomes 6, 7, and 22 and a dearth on chromosome 12. This distribution is significantly different from that of a sample of reciprocal translocations ascertained for a malformed child. In both samples the breakpoints seem associated with fragile sites more frequently than expected by chance. An analysis of the potential and effective chromosome imbalance suggests that in subjects with unbalanced chromosomes survival is correlated with a minimum imbalance.

Cytogenetic abnormalities in 1162 couples with recurrent miscarriages in Southern region of India: report and review

“…The size of the chromosomal segment involved the frequency of the breakpoints and their positions have a vital role in reproduction. In translocations, breakpoints are nonrandom, especially in couples with Bad Obstetric History [25].The frequently involved chromosomes in the translocations in the present study were 1, 5, 7, 9, 14 & 16. The molecular characterization of the three novel translocation cases mentioned in this study was not reported in the literature involving those breakpoint regions.…”

9p Deletion and distal 9q duplication due to a paternal pericentric inversion 9(p22q32)

“…It has been found that the relative risk of inv(9)(qh) positive couples having spontaneous abortions compared to inv(9)(qh) negative couples is not significantly increased statistically (De la Chapetla et al, 1974;Campana et aL, 1986). In the father of our proband the inverted segment was so large that the frequency of abortion might be low, The three spontaneous abortions observed in our family might have been by chance.…”

Clinical applications of two-color telomeric fluorescence in situ hybridization for prenatal diagnosis: Identification of chromosomal translocation in five families with recurrent miscarriages or a child with multiple congenital anomalies

“…In the interphase diagnosis, we should be careful to use some FISH probes, such as the 16qter probes in family 1, which produce weak cross-hybridization to a few other telomeres (Ning et al 1996), although this cross-hybridization is negligible in the metaphase diagnosis. Campana et al (1986) reported that a reciprocal translocation carrier was found by conventional cytogenetics technique in 181/5445 (3.3%) of the couples who had medical histories of recurrent abortions. On the other hand, Flint et al (1995) reported that three in 99 idiopathic mentally retarded patients with normal routine karyotypes had subtelomeric chromosomal rearrangements using hypervariable DNA polymorphism analysis.…”