Pericentric inversions

Abstract

A review is given of the incidence, cytogenetics, and biologic relevance of pericentric inversions (pii). In 251 cases in the literature and our patients, 96 different inversion forms with different breakpoints are found. Eighteen of these cases have been observed several times in unrelated families; they are classified as types. The problem of pii in the heterochromatic regions of chromosomes 1 and 9 is especially emphasized and the investigations required are pointed out. The significance of the individual pii is checked with regard to their behavior in meiosis and their phenotypical relevance. An approximately 1:1 segregation is found. Fertility, stillbirth, and rates of abortion are not statistically altered. The gonadal findings available at present in man are reported and commented on. The occurrence of aneusomic recombinants among the live offspring of carriers shows a marked dependence on the length of the relative inversion segments. Since these are distinctly below average in inversion types, they only result in recombinants in exceptional cases. Certain pointers to an above-random common occurrence of other chromosomal aberrations are not found in families with pii. A correlation between pii and clinical symptoms likewise cannot be detected. However, in this connection it is pointed out that trisomic mosaics were observed jointly with pii(9) and pii(22). The review is completed by a brief examination of the literature concerning the significance of pii in evolution.

Evolutionary conserved chromosomal segments in the human karyotype are bounded by unstable chromosome bands

“…3) involved in chromosome breaks because of Robertsonian and constitutional translocations, and paracentric and pericentric inversions described in clinical cytogenetics as well as bands implicated in neoplasias (Kaiser, 1984;Fryns et al, 1986;A French collaborative study, 1986;Kleezkowska et al, 1987;Madan, 1995;Cohen et al, 1996;Mitelman et al, 1997), we were able to show that 73 % (46 out of 63) of these human chromosome bands are co-localized in bands where fragile sites, intrachromosomal telomericlike sequences, bands significantly affected by X irradiation and/or evolutionary chromosomal bands have been described. Therefore, and in summary, the human genome, organized in chromosome forms, does not represent a uniform structure.…”

“…Intrachromosomal telomeric-like sequences studies: Azzalin et al (1997), Ruiz-Herrera et al (2002b) and Ruiz-Herrera et al (2004). Clinical cytogenetic studies: Kaiser (1984), Fryns et al (1986), A French collaborative study (1986), Kleezkowska et al (1987), Madan (1995), Cohen et al (1996) and Mitelman et al (1997).…”

“…Human evolutionary chromosome bands which are boundaries for ancestral chromosome segments (see Fig. 1) in different species from different orders (Smeets and Van de Klunder, 1990); red stars: human chromosome bands significantly affected by X irradiation (Barrios et al, 1989); green stars: M. fascicularis chromosome bands significantly affected by X irradiation located in the homologous human chromosome band (Borrell et al, 1998a, b); i: evolutionary inversions; f: evolutionary fusion/fission events; b: breakpoints detected in human pathologies (Kaiser, 1984;Fryns et al, 1986;A French collaborative study, 1986;Kleezkowska et al, 1987;Madan, 1995;Cohen et al, 1996;Mitelman et al, 1997).…”

Prenatal Diagnosis of Common Arterial Trunk: A Single-Center's Experience

“…One fetus showed robertsonian translocation which is not thought to be related with CAT (case 7 in table 1). Another case of inv(9)(p12q13) was found, which is the most common pericentric inversion in the human karyotype and is considered to be a chromosomal variant in the normal population (case 11 in table 1) [18,19]. However, although clinically significant chromosomal abnormalities were not detected, we cannot conclude that the present series of CAT cases had a significantly lower incidence of chromosomal abnormalities than other series because of the small study population, which is the primary limitation of our study.…”

A Dysmorphic Child with a Pericentric Inversion of Chromosome 8

“…Pericentric inversions are among the frequent chromosomal rearrangements associated with genetic disorders with a frequency of 1-2% [1, 2]. Pericentric inversions result from a two-break event which occurs between the short (p) and the long arms (q) within the chromosome followed by a 180° rotation of the intercalary segment.…”