Rare chromosome 20 variants encountered during prenatal diagnosis

Petersen, Michael B.

doi:10.1002/pd.1970060504

Cited by 12 publications

(5 citation statements)

References 14 publications

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“…The association of heteromorphisms and interchromosomal heterochromatin interactions with reproductive loss and other pathology is yet to be substantiated, and until evidence to the contrary is presented they are considered to be of no clinical significance.7 What is of importance, however, is that variants continue to be reported and structurally resolved for purposes of genetic counselling, prenatal diagnosis, and frequency in the population. 3 We thus consider this heteromorphism in chromosome 20 to be a normal familial variant with no pathological significance.…”

Section: Discussionmentioning

confidence: 99%

A rare heteromorphism of chromosome 20 and reproductive loss.

Romain

Whyte²,

Callen³

et al. 1991

Journal of Medical Genetics

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A rare centromeric heterochromatic variant of chromosome 20 was encountered during investigations in a couple with repeated miscarriages. The enlarged segment was G and C band positive and stained positively by Giemsa II. In situ hybridisation of the biotinylated alphoid probe D2OZ1 specific for the centromere of chromosome 20 to metaphase celis confirmed the presence of amplified sequences adjacent to the centromere. The variant was found to be familial and was evaluated as having no clinical significance.We have used, in addition to well established banding techniques, in situ hybridisation with the biotinylated probe D2OZ1 to evaluate an uncommon heteromorphism observed in the centromere region of chromosome 20. Differences in fluorescent intensity for this region have been described,' 2 but only rarely when heterochromatin has extended into either the long or short arm or both.3 Materials and methods CYTOGENETICSChromosomes were obtained from PHA stimulated lymphocyte cultures and investigated by routine C,

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Section: Discussionmentioning

confidence: 99%

A rare heteromorphism of chromosome 20 and reproductive loss.

Romain

Whyte²,

Callen³

et al. 1991

Journal of Medical Genetics

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“…To our knowledge, all cases of chromosomal polymorphisms described in fetuses have been shown to be diagnosed fortuitously and inherited from one healthy parent [5,6,8,13]. Only the case described by Fryns et al [11] was found in a fetus carrying multiple malformations, but the variant chromosome 20 was also present in his phenotypically normal mother.…”

Section: Discussionmentioning

confidence: 94%

Prenatal Diagnosis of a Large Centromeric Heteromorphism of Chromosome 12: Implications for Genetic Counseling

et al. 2003

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“…In recent years, more and more studies had focused on the chromosomal heteromorphisms [22] which can be verified by the application of C-banding and AgNOR - staining techniques. Several other centromeric variants, verified by C-banding in the course of a prenatal diagnosis [23–28], have been described for chromosomes 5, 6, 12, 18, 19 or 20. Our data presented a rare heteromorphism on chromosome 19 and it was different from the four different classes that Crossen noted [29].…”

Section: Discussionmentioning

confidence: 99%

C-banding and AgNOR-staining were still effective complementary methods to indentify chromosomal heteromorphisms and some structural abnormalities in prenatal diagnosis

Zhu

Cai

et al. 2019

Mol Cytogenet

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Background In prenatal diagnosis, CMA has begun to emerge as a favorable alternative to karyotype analysis, but it could not identify balanced translocations, triploidies, inversion and heteromorphisms. Therefore, conventional cytogenetic and specific staining methods still play an important role in the work-up of chromosome anomaly. This study investigated the application of C-banding and AgNOR-staining techniques in prenatal diagnosis of chromosomal heteromorphisms and some structure abnormalities. Results Among the 2970 samples, the incidence of chromosomal heteromorphisms was 8.79% (261/2970). The most frequent was found to be chromosome Y (2.93%, 87/2970), followed by chromosome 1 (1.65 %, 49/2970), 9 (1.52 %, 45/2970), 22 (0.77 %, 23/2970) and 15 (0.64 %, 19/2970). We compared the incidence of chromosomal heteromorphisms between recurrent spontaneous abortion (RSA) group and control group. The frequency of autosomal hetermorphisms in RSA group was 7.63% higher than that in control group (5.78%), while the frequency of Y chromosomal heteromorphisms was 4.76% lower than that in control group (5.71%). Here we summarized 4 representative cases, inv (1) (p12q24), psu dic (4;17) (p16.3;p13.3), r(X)(p11; q21) and an isodicentric bisatellited chromosome to illustrate the application of C-banding or AgNOR-staining, CMA or NGS was performed to detect CNVs if necessary. Conclusions This study indicated that C-banding and AgNOR-staining were still effective complementary methods to identify chromosomal heteromorphisms and marker chromosomes or some structural rearrangements involving the centromere or acrocentric chromosomes. Our results suggested that there was no evidence for an association between chromosomal heteromorphisms and infertility or recurrent spontaneous abortions. Undoubtedly, sometimes we needed to combine the results of CMA or CNV-seq to comprehensively reflect the structure and aberration of chromosome segments. Thus, accurate karyotype reports and genetic counseling could be provided.

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Rare chromosome 20 variants encountered during prenatal diagnosis

Cited by 12 publications

References 14 publications

A rare heteromorphism of chromosome 20 and reproductive loss.

A rare heteromorphism of chromosome 20 and reproductive loss.

Prenatal Diagnosis of a Large Centromeric Heteromorphism of Chromosome 12: Implications for Genetic Counseling

C-banding and AgNOR-staining were still effective complementary methods to indentify chromosomal heteromorphisms and some structural abnormalities in prenatal diagnosis

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