Paracentric inversions: a review

Madan, K.

doi:10.1007/bf00197403

Cited by 81 publications

(82 citation statements)

References 67 publications

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“…Moreover, we found similar frequencies of the inversion in blood samples and amniocytes, which indicates that this is a silent variant. Most of the paracentric inversions identified in cytogenetic laboratories are not associated with any specific phenotypic abnormalities and the risk of heterozygotes having offspring with an unbalanced karyotype is expected to be small [Madan, 1995;Thomas et al, 2008]. Our results are also consistent with previous findings of cytogenetic paracentric inversions, which suggest that the majority (66%) is inherited [Pettenati et al, 1995].…”

Section: Discussionsupporting

confidence: 91%

A chromosome 10 variant with a 12 Mb inversion [inv(10)(q11.22q21.1)] identical by descent and frequent in the Swedish population

Entesarian

Carlsson

Mansouri

et al. 2009

American J of Med Genetics Pt A

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We identified a paracentric inversion of chromosome 10 [inv(10)(q11.22q21.1)] in 0.20% of Swedish individuals (15/7,439) referred for cytogenetic analysis. A retrospective analysis of 8,896 karyotypes from amniocenteses in Sweden revealed a carrier frequency of 0.079% (7/8,896) for the inversion. Cloning and detailed analysis of the inversion breakpoint regions show enrichment for interspersed repeat elements and AT-stretches. The centromeric breakpoint coincides with that of a predicted inversion from HapMap data, which suggests that this region is involved in several chromosome 10 variants. No known gene or predicted transcript are disrupted by the inversion which spans approximately 12 Mb. Carriers from four nonrelated Swedish families have identical inversion breakpoints and haplotype analysis confirmed that the rearrangement is identical by descent. Diagnosis was retrieved in 6 out of the 15 carriers referred for cytogenetic analysis. No consistent phenotype was found to be associated with the inversion. Our study demonstrates that the inv(10)(q11.22q21.1) is a rare and inherited chromosome variant with a broad geographical distribution in Sweden.

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Section: Discussionsupporting

confidence: 91%

A chromosome 10 variant with a 12 Mb inversion [inv(10)(q11.22q21.1)] identical by descent and frequent in the Swedish population

Entesarian

Carlsson

Mansouri

et al. 2009

American J of Med Genetics Pt A

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“…A rather old and common origin of the abnormality is hypothesized. chromosome Madan (1995) and Villa et al (1995).…”

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confidence: 99%

A pericentric inversion of chromosome 4 in pigs

Ducos¹,

Pinton²,

Séguéla³

et al. 1997

Genet. Sel. Evol.

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Summary -The main French porcine artificial insemination centre recently decided to carry out a systematic chromosomal evaluation of the animals used for pure-breeding purposes. This practice has allowed the identification of a new pericentric inversion affecting chromosome 4, in four Large White boars originating from four different herds. The cytogenetic evaluation by means of the GTG-banding technique revealed an inversion of the pericentric part of the chromosome, after double breaks, the first one in the 4q2.3 pale band of the long arm, and the second one in the upper border of the 4pl.4 dark band of the short arm. The chromosomal rearrangement could be described, according to the standard nomenclature, as 38,XY,inv(4)(p14q23). This interpretation has been confirmed

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“…Whether this represents a genuine rarity for such homozygosity or is due to underreporting is uncertain. For example, if one assumes a frequency for t(13;14) of 7 in 10 000 in the normal population, 11 then the probability of homozygosity in random mating between unrelated individuals is B1.2Â10 À7 (0.0007Â0.0007Â0.25). This is in effect approximately 1 in 8 200 000 conceptions, and if one accepts that RBT homozygotes are phenotypically normal, then one may expect a similar frequency of homozygous liveborns.…”

Section: Discussionmentioning

confidence: 99%

“…8 Chromosomal inversions arise from an intrachromosomal break and subsequent intrachromosomal rearrangement, and may be divided into pericentric and paracentric forms based on the position of the breakpoints relative to the centromere. [9][10][11][12] The majority of all inversions (66%) are of pericentric type. 12 As with reciprocal translocations, inversions may involve any chromosome and most are considered unique.…”

Section: Introductionmentioning

confidence: 99%

Homozygosity for constitutional chromosomal rearrangements: a systematic review with reference to origin, ascertainment and phenotype

O’Neill¹

2010

J Hum Genet

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Chromosomal translocations and inversions are present in B0.6-1% of individuals. Although the majority are inherited, and the familial transmission across generations is well reported, reports of homozygosity are relatively rare, with most data in the form of individual case reports. A systematic review of all published cases was performed with particular attention to origin, ascertainment and phenotype of the reported homozygosity. A total of 10 cases of Robertsonian translocation (RBT), 6 reciprocal translocation and 19 cases of inversion homozygosity were identified. In RBT homozygosity, the majority of individuals are phenotypically normal, arise from inbreeding within a family that carries a familial translocation, and are ascertained following identification of an existing familial rearrangement rather than any feature specific to the homozygosity. In addition, they are fertile and as expected, their offspring are heterozygous for the translocation. For reciprocal translocations, homozygosity arises in individuals born to related parents from a family who harbor a unique familial translocation. Ascertainment is following investigation of phenotypic abnormalities resulting from consanguinity per se and/or the unmasking of a specific gene mutation. For chromosomal inversions, homozygosity may originate from either related or non-consanguinous parentage. Although many cases are ascertained because of an associated phenotypic abnormality, a high proportion of cases are of normal phenotype and a direct causal relationship is uncertain. There are fewer reports of both Robertsonian and inversion homozygosity than may be expected from the relative frequencies of each class within the population. Keywords: consanguinity; homozygosity; pericentric inversion; reciprocal translocation; Robertsonian translocation INTRODUCTION Structural chromosomal rearrangements detected under light microscopy fall under three broad categories: Robertsonian translocations (RBTs), reciprocal translocations and chromosomal inversions. 1 Data suggest that such rearrangements are present in B0.6-1% of individuals, with reported differences dependant on the population studied (for example unselected newborns or selected prenatal or population studies) and the level of banding techniques used. [2][3][4][5][6] Additional considerations include the proportion of balanced versus unbalanced abnormalities and origin of the rearrangement; that is whether inherited or de novo. The relative prevalence and the underlying mutations rate vary for each category of rearrangement and for specific types within each category.RBTs include non-homologous translocations and homologous forms, with non-homologous RBTs being far more common. 1 Nonhomologous RBTs are the most common recurrent whole-scale structural chromosomal rearrangement in humans being found in approximately 1 in 1000 live births. 2,5 These arise from whole arm exchanges between the short arms of the acrocentric chromosomes (13-15, 21 and 22) to form a single-metacentric chromosome.

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Paracentric inversions: a review

Cited by 81 publications

References 67 publications

A chromosome 10 variant with a 12 Mb inversion [inv(10)(q11.22q21.1)] identical by descent and frequent in the Swedish population

A chromosome 10 variant with a 12 Mb inversion [inv(10)(q11.22q21.1)] identical by descent and frequent in the Swedish population

A pericentric inversion of chromosome 4 in pigs

Homozygosity for constitutional chromosomal rearrangements: a systematic review with reference to origin, ascertainment and phenotype

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