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

2020 ◽  
Vol 23 (2) ◽  
pp. 25-34
Author(s):  
NB Satkin ◽  
B Karaman ◽  
S Ergin ◽  
H Kayserili ◽  
IH Kalelioglu ◽  
...  
Keyword(s):  
Comparative Genomic Hybridization ◽  
Array Comparative Genomic Hybridization ◽  
De Novo ◽  
Chromosomal Rearrangements ◽  
Chromosomal Microarray ◽  
Comparative Genomic ◽  
Gene Gain ◽  
Loss Of Function ◽  
Genomic Hybridization ◽  
Ultrasound Findings

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.

scholarly journals Subtelomeric Rearrangements: Presentation of 21 Probands with Emphasis on Familial Cases

2019 ◽  
Vol 32 (7-8) ◽  
pp. 529
Author(s):  
Ana Rita Soares ◽  
Gabriela Soares ◽  
Manuela Mota-Freitas ◽  
Natália Oliva-Teles ◽  
Ana Maria Fortuna
Keyword(s):  
Intellectual Disability ◽  
Comparative Genomic Hybridization ◽  
Chromosomal Abnormality ◽  
Array Comparative Genomic Hybridization ◽  
De Novo ◽  
Family Members ◽  
Comparative Genomic ◽  
Genomic Hybridization ◽  
Subtelomeric Rearrangements

Introduction: Intellectual disability affects 2% – 3% of the general population, with a chromosomal abnormality being found in 4% – 28% of these patients and a cryptic subtelomeric abnormality in 3% – 16%. In most cases, these subtelomeric rearrangements are submicroscopic, requiring techniques other than conventional karyotype for detection. They may be de novo or inherited from an affected parent or from a healthy carrier of a balanced chromosomal abnormality. The aim of this study was to characterize patients from our medical genetics center, in whom both a deletion and duplication in subtelomeric regions were found.Material and Methods: Clinical and cytogenetic characterization of 21 probands followed at our center, from 1998 until 2017, with subtelomeric rearrangements.Results: There were 21 probands from 19 families presenting with intellectual disability and facial dysmorphisms. Seven had behavior changes, five had epilepsy and 14 presented with some other sign or symptom. Four had chromosomal abnormalities detected by conventional karyotype and four were diagnosed by array-comparative genomic hybridization. In four cases, parental studies were not possible. The online mendelian inheritance in man classification was provided whenever any of the phenotypes (deletion or duplication syndrome) was dominant.Discussion: Patients and relevant family members were clinically and cytogenetically characterized. Although rare, subtelomeric changes are a substantial cause of syndromic intellectual disability with important familial repercussions. It is essential to remember that a normal array-comparative genomic hybridization result does not exclude a balanced rearrangement in the parents.Conclusion: Parental genetic studies are essential not only for a complete characterization of the rearrangement, but also for accurate genetic counselling and screening of family members at risk for recurrence.

scholarly journals A novel de novo paracentric inversion [inv(20)(q13.1q13.3)] accompanied by an 11q14.3-q21 microdeletion in a pediatric patient with an intellectual disability

2018 ◽  
Vol 21 (2) ◽  
pp. 63-67
Author(s):  
S Zachaki ◽  
E Kouvidi ◽  
A Mitrakos ◽  
L Lazaros ◽  
A Pantou ◽  
...  
Keyword(s):  
Mental Retardation ◽  
Comparative Genomic Hybridization ◽  
Array Comparative Genomic Hybridization ◽  
De Novo ◽  
Chromosomal Abnormalities ◽  
Mendelian Inheritance ◽  
Paracentric Inversion ◽  
Comparative Genomic ◽  
Published Data ◽  
Genomic Hybridization

Abstract A novel de novo paracentric inversion of the long arm of chromosome 20 [inv(20)(q13.1q13.3)], detected by conventional karyotyping in a 14-year-old boy with mental retardation is described. Further investigation by array comparative genomic hybridization (aCGH) revealed that the 20q inversion was not accompanied by microdeletions/microduplications containing disease-associated genes near or at the breakpoints. Two deletions at chromosomal regions 11q14.3q21 and 20q12 of 4.5 and 1.97 Mb size, respectively, containing important online Mendelian inheritance in man (OMIM) genes, were detected. The 4.5Mb 11q14.3q21 microdeletion was contained within a region that is involved, in most of the reported cases, with the interstitial 11q deletion and may be related to the mental retardation and developmental delay present in the patient. On the other hand, the published data about the 20q12 microdeletion are very few and it is not possible to correlate this finding with our patient’s phenotype. This case report contributes to the description of a new chromosomal entity, not previously reported, and is therefore important, especially in prenatal diagnosis and management of patients. Array comparative genomic hybridization has proven a useful technique for detecting submicroscopic rearrangements and should be offered prenatally, especially in cases of de novo karyotypically balanced chromosomal inversions or translocations in order to unveil other unbalanced chromosomal abnormalities such as deletions and amplifications.

A de novo Proximal 6q Deletion Confirmed by Array Comparative Genomic Hybridization

2010 ◽  
Vol 30 (1) ◽  
pp. 84-88 ◽  
Author(s):  
Kwang-Sook Woo ◽  
Ji-Eun Kim ◽  
Kyung-Eun Kim ◽  
Myo-Jing Kim ◽  
Jae-Ho Yoo ◽  
...  
Keyword(s):  
Comparative Genomic Hybridization ◽  
Array Comparative Genomic Hybridization ◽  
De Novo ◽  
Comparative Genomic ◽  
Genomic Hybridization
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