<abstract xmlns="http://www.w3.org/1999/xhtml"><p>Carriers of apparently balanced chromosomal rearrangements (ABCRs) have a 2-3-fold higher risk of carrying an abnormal phenotype, when compared to the average population. Apparently balanced chromosomal rearrangements can be imbalanced at the submicroscopic level, and changes in the gene structure, formation of a new chimeric gene, gain or loss of function of the genes and altered imprinting pattern may also affect the phenotype. Chromosomal microarray (CMA) is an efficient tool to detect submicroscopic imbalances at the breakpoints as well as in the whole genome. We aimed to determine the effectiveness of array-comparative genomic hybridization (aCGH) application in phenotypically affected cases with ABCRs at a single center from Turkey. Thirty-four affected cases (13 prenatal, 21 postnatal) carrying ABCRs were investigated with CMA. In postnatal series, ABCRs were familial in 7 and <italic>de novo</italic> in 14 cases. Seven <italic>de novo</italic> cases were imbalanced (in postnatal series 33.3% and in <italic>de novo</italic> cases 50.0%). Out of 13 prenatal cases, five were familial and eight were <italic>de novo</italic> in origin and two <italic>de novo</italic> cases were imbalanced (in 15.4% prenatal series and in 25.0% <italic>de novo</italic> cases). No cryptic imbalance was observed in familial cases. The anomaly rates with array studies ranged between 14.3-25.0% in familial and between 20.0-57.5% in <italic>de novo</italic> cases of postnatal series in the literature. Studies focused on prenatal ABCR cases with abnormal ultrasound findings are limited and no submicroscopic imbalance was reported in the cohorts. When <italic>de novo</italic> postnatal or prenatal results were combined, the percentage of abnormalities detected by CMA was 40.9%. Taking this contribution into consideration, all ABCRs should be investigated by CMA even if the fetal ultrasound findings are normal.</p></abstract>

Carriers of apparently balanced chromosomal rearrangements (ABCRs) have a 2-3-fold higher risk of carrying an abnormal phenotype, when compared to the average population. Apparently balanced chromosomal rearrangements can be imbalanced at the submicroscopic level, and changes in the gene structure, formation of a new chimeric gene, gain or loss of function of the genes and altered imprinting pattern may also affect the phenotype. Chromosomal microarray (CMA) is an efficient tool to detect submicroscopic imbalances at the breakpoints as well as in the whole genome. We aimed to determine the effectiveness of array-comparative genomic hybridization (aCGH) application in phenotypically affected cases with ABCRs at a single center from Turkey. Thirty-four affected cases (13 prenatal, 21 postnatal) carrying ABCRs were investigated with CMA. In postnatal series, ABCRs were familial in 7 and de novo in 14 cases. Seven de novo cases were imbalanced (in postnatal series 33.3% and in de novo cases 50.0%). Out of 13 prenatal cases, five were familial and eight were de novo in origin and two de novo cases were imbalanced (in 15.4% prenatal series and in 25.0% de novo cases). No cryptic imbalance was observed in familial cases. The anomaly rates with array studies ranged between 14.3-25.0% in familial and between 20.0-57.5% in de novo cases of postnatal series in the literature. Studies focused on prenatal ABCR cases with abnormal ultrasound findings are limited and no submicroscopic imbalance was reported in the cohorts. When de novo postnatal or prenatal results were combined, the percentage of abnormalities detected by CMA was 40.9%. Taking this contribution into consideration, all ABCRs should be investigated by CMA even if the fetal ultrasound findings are normal.

Array-comparative genomic hybridization results in clinically affected cases with apparently balanced chromosomal rearrangements

Balkan Journal of Medical Genetics

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Carriers of apparently balanced chromosomal rearrangements (ABCRs) have a 2-3-fold higher risk of carrying an abnormal phenotype, when compared to the average...

Array-comparative genomic hybridization results in clinically affected cases with apparently balanced chromosomal rearrangements

Article Category: Original article

Published Online: Mar 23, 2021

Page range: 25 - 34

DOI: https://doi.org/10.2478/bjmg-2020-0026

Keywords
Apparently balanced structural chromosomal abnormalities (ABCRs), Array-comparative genomic hybridization (aCGH), Chromosomal microarray (CMA), Cryptic genomic imbalances, Fetal ultrasound findings

© 2020 Satkin NB, Karaman B, Ergin S, Kayserili H, Kalelioglu IH, Has R, Yuksel A, Basaran S, published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Array-comparative genomic hybridization results in clinically affected cases with apparently balanced chromosomal rearrangements

Article Category: Original article

Published Online: Mar 23, 2021

Page range: 25 - 34

DOI: https://doi.org/10.2478/bjmg-2020-0026

KeywordsApparently balanced structural chromosomal abnormalities (ABCRs), Array-comparative genomic hybridization (aCGH), Chromosomal microarray (CMA), Cryptic genomic imbalances, Fetal ultrasound findings

© 2020 Satkin NB, Karaman B, Ergin S, Kayserili H, Kalelioglu IH, Has R, Yuksel A, Basaran S, published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
Apparently balanced structural chromosomal abnormalities (ABCRs), Array-comparative genomic hybridization (aCGH), Chromosomal microarray (CMA), Cryptic genomic imbalances, Fetal ultrasound findings