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Szczawińska-Popłonyk A, Schwartzmann E, Chmara Z, Głukowska A, Krysa T, Majchrzycki M, Olejnicki M, Ostrowska P, Babik J. Chromosome 22q11.2 Deletion Syndrome: A Comprehensive Review of Molecular Genetics in the Context of Multidisciplinary Clinical Approach. Int J Mol Sci 2023; 24:ijms24098317. [PMID: 37176024 PMCID: PMC10179617 DOI: 10.3390/ijms24098317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 04/30/2023] [Accepted: 05/03/2023] [Indexed: 05/15/2023] Open
Abstract
The 22q11.2 deletion syndrome is a multisystemic disorder characterized by a marked variability of phenotypic features, making the diagnosis challenging for clinicians. The wide spectrum of clinical manifestations includes congenital heart defects-most frequently conotruncal cardiac anomalies-thymic hypoplasia and predominating cellular immune deficiency, laryngeal developmental defects, midline anomalies with cleft palate and velar insufficiency, structural airway defects, facial dysmorphism, parathyroid and thyroid gland hormonal dysfunctions, speech delay, developmental delay, and neurocognitive and psychiatric disorders. Significant progress has been made in understanding the complex molecular genetic etiology of 22q11.2 deletion syndrome underpinning the heterogeneity of clinical manifestations. The deletion is caused by chromosomal rearrangements in meiosis and is mediated by non-allelic homologous recombination events between low copy repeats or segmental duplications in the 22q11.2 region. A range of genetic modifiers and environmental factors, as well as the impact of hemizygosity on the remaining allele, contribute to the intricate genotype-phenotype relationships. This comprehensive review has been aimed at highlighting the molecular genetic background of 22q11.2 deletion syndrome in correlation with a clinical multidisciplinary approach.
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Affiliation(s)
- Aleksandra Szczawińska-Popłonyk
- Department of Pediatric Pneumonology, Allergy and Clinical Immunology, Institute of Pediatrics, Karol Marcinkowski University of Medical Sciences, 60-572 Poznań, Poland
| | - Eyal Schwartzmann
- Medical Student Scientific Society, English Division, Karol Marcinkowski University of Medical Sciences, 60-572 Poznań, Poland
| | - Zuzanna Chmara
- Medical Student Scientific Society, Karol Marcinkowski University of Medical Sciences, 60-572 Poznań, Poland
| | - Antonina Głukowska
- Medical Student Scientific Society, Karol Marcinkowski University of Medical Sciences, 60-572 Poznań, Poland
| | - Tomasz Krysa
- Medical Student Scientific Society, Karol Marcinkowski University of Medical Sciences, 60-572 Poznań, Poland
| | - Maksymilian Majchrzycki
- Medical Student Scientific Society, Karol Marcinkowski University of Medical Sciences, 60-572 Poznań, Poland
| | - Maurycy Olejnicki
- Medical Student Scientific Society, Karol Marcinkowski University of Medical Sciences, 60-572 Poznań, Poland
| | - Paulina Ostrowska
- Medical Student Scientific Society, Karol Marcinkowski University of Medical Sciences, 60-572 Poznań, Poland
| | - Joanna Babik
- Gynecology and Obstetrics with Pregnancy Pathology Unit, Franciszek Raszeja Municipal Hospital, 60-834 Poznań, Poland
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Bao B, Hu H, Chen L, Lu S, Tang Q, Liang Z. SNP and DNA methylation analyses of a monozygotic twins discordant for complete endocardial cushion defect: a case report. Am J Transl Res 2022; 14:8271-8278. [PMID: 36505317 PMCID: PMC9730093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Accepted: 10/24/2022] [Indexed: 12/15/2022]
Abstract
The exact cause of complete endocardial cushion defect (ECD) is still unknown. This report describes a unique pair of monozygotic twins (MZ twins) discordant for ECD. The chromosome karyotyping analysis revealed normal karyotype of 46, XY, 16qh+ and mat in both MZ twins. A genome-wide analysis of DNA using the Affymetrix SNP 6.0 revealed identical genotyping of single nucleotide polymorphisms (SNPs) and copy number variations (CNVs). An extensive methylation assay was carried out by NimbleGen 3 × 720 K CpG Island Plus RefSeq Promoter Arrays to analyze the potential epigenetic differences. The DNA methylation profiles of the affected twin seemed increased compared with that of the unaffected twin. However, further validation of Notch1 promoter hypermethylation and six top-ranked differentially methylated CpG sites by sodium bisulfate modification and methylation-specific PCR, failed to reveal consistent methylation differences between the twins. Other relevant factors, such as heritability and penetrance of the condition that place the MZ twins near to a threshold for ECD or variations in local epigenetic events in the twins' heart tissues, are probably responsible for the phenotypic discordance.
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Affiliation(s)
- Bihui Bao
- Department of Obstetrics and Gynecology, Qingbaijiang Women’s and Children’s Hospital (Maternal and Child Health Hospital), West China Second University Hospital, Sichuan UniversityChengdu 610300, Sichuan, China
| | - Hua Hu
- Department of Obstetrics and Gynecology, The Second Affiliated Hospital (Xinqiao Hospital), Army Medical UniversityChongqing 400037, China
| | - Limei Chen
- Department of Obstetrics and Gynecology, Qingbaijiang Women’s and Children’s Hospital (Maternal and Child Health Hospital), West China Second University Hospital, Sichuan UniversityChengdu 610300, Sichuan, China
| | - Shiyong Lu
- Department of Obstetrics and Gynecology, Qingbaijiang Women’s and Children’s Hospital (Maternal and Child Health Hospital), West China Second University Hospital, Sichuan UniversityChengdu 610300, Sichuan, China
| | - Qifeng Tang
- Department of Anesthesiology, Shanghai Hechuan-Rhine TCM HospitalShanghai 201103, China
| | - Zhiqing Liang
- Department of Obstetrics and Gynecology, The First Affiliated Hospital (Southwest Hospital), Army Medical UniversityChongqing 400038, China
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Gavril EC, Popescu R, Nucă I, Ciobanu CG, Butnariu LI, Rusu C, Pânzaru MC. Different Types of Deletions Created by Low-Copy Repeats Sequences Location in 22q11.2 Deletion Syndrome: Genotype-Phenotype Correlation. Genes (Basel) 2022; 13:2083. [PMID: 36360320 PMCID: PMC9690028 DOI: 10.3390/genes13112083] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 10/21/2022] [Accepted: 11/08/2022] [Indexed: 09/19/2023] Open
Abstract
The most frequent microdeletion, 22q11.2 deletion syndrome (22q11.2DS), has a wide and variable phenotype that causes difficulties in diagnosis. 22q11.2DS is a contiguous gene syndrome, but due to the existence of several low-copy-number repeat sequences (LCR) it displays a high variety of deletion types: typical deletions LCR A-D-the most common (~90%), proximal deletions LCR A-B, central deletions (LCR B, C-D) and distal deletions (LCR D-E, F). METHODS We conducted a retrospective study of 59 22q11.2SD cases, with the aim of highlighting phenotype-genotype correlations. All cases were tested using MLPA combined kits: SALSA MLPA KIT P245 and P250 (MRC Holland). RESULTS most cases (76%) presented classic deletion LCR A-D with various severity and phenotypic findings. A total of 14 atypical new deletions were identified: 2 proximal deletions LCR A-B, 1 CES (Cat Eye Syndrome region) to LCR B deletion, 4 nested deletions LCR B-D and 1 LCR C-D, 3 LCR A-E deletions, 1 LCR D-E, and 2 small single gene deletions: delDGCR8 and delTOP3B. CONCLUSIONS This study emphasizes the wide phenotypic variety and incomplete penetrance of 22q11.2DS. Our findings contribute to the genotype-phenotype data regarding different types of 22q11.2 deletions and illustrate the usefulness of MLPA combined kits in 22q11.2DS diagnosis.
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Affiliation(s)
- Eva-Cristiana Gavril
- Department of Medical Genetics, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, University Street, No 16, 700115 Iasi, Romania
- Investigații Medicale Praxis, St. Moara de Vant No 35, 700376 Iasi, Romania
| | - Roxana Popescu
- Department of Medical Genetics, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, University Street, No 16, 700115 Iasi, Romania
- Department of Medical Genetics “Saint Mary” Emergency Children’s Hospital, St. Vasile Lupu No 62, 700309 Iasi, Romania
| | - Irina Nucă
- Department of Medical Genetics, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, University Street, No 16, 700115 Iasi, Romania
- Investigații Medicale Praxis, St. Moara de Vant No 35, 700376 Iasi, Romania
| | - Cristian-Gabriel Ciobanu
- Department of Medical Genetics, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, University Street, No 16, 700115 Iasi, Romania
| | - Lăcrămioara Ionela Butnariu
- Department of Medical Genetics, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, University Street, No 16, 700115 Iasi, Romania
- Department of Medical Genetics “Saint Mary” Emergency Children’s Hospital, St. Vasile Lupu No 62, 700309 Iasi, Romania
| | - Cristina Rusu
- Department of Medical Genetics, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, University Street, No 16, 700115 Iasi, Romania
- Department of Medical Genetics “Saint Mary” Emergency Children’s Hospital, St. Vasile Lupu No 62, 700309 Iasi, Romania
| | - Monica-Cristina Pânzaru
- Department of Medical Genetics, Faculty of Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, University Street, No 16, 700115 Iasi, Romania
- Department of Medical Genetics “Saint Mary” Emergency Children’s Hospital, St. Vasile Lupu No 62, 700309 Iasi, Romania
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Lin I, Afshar Y, Goldstein J, Grossman J, Grody WW, Quintero-Rivera F. Central 22q11.2 deletion (LCR22 B-D) in a fetus with severe fetal growth restriction and a mother with severe systemic lupus erythematosus: Further evidence of CRKL haploinsufficiency in the pathogenesis of 22q11.2 deletion syndrome. Am J Med Genet A 2021; 185:3042-3047. [PMID: 34196458 DOI: 10.1002/ajmg.a.62346] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 04/03/2021] [Accepted: 04/22/2021] [Indexed: 12/25/2022]
Abstract
22q11.2 deletion syndrome (22q11.2 DS, MIM #188400) is the most common chromosomal microdeletion with an incidence of 1 in 4000 live births. 22q11.2 DS patients present with varying penetrance and a broad phenotypic spectrum including dysmorphic features, congenital heart defects, hypoplastic thymus and T-cell deficiency, and hypocalcemia. The typical deletion spans 3 Mb between 4 large blocks of repetitive DNA, known as low copy repeats (LCRs), on chromosome 22 (LCR22) A and D. This deletion is found in ~85% of 22q11.2 DS patients, while only 4-5% have central LCR22B-D (1.5 Mb) and LCR22C-D (0.7 Mb) deletions. We report on a prenatally diagnosed, inherited case of central LCR22B-D 22q11.2 DS, born to a 22-year-old female with multiple autoimmune disorders. These include Sjogren's-syndrome-related antigen A (SSA+) severe systemic lupus erythematosus (SLE) with cutaneous and discoid components and seronegative antiphospholipid syndrome. Amniocentesis was performed due to fetal growth restriction (FGR). FISH with TUPLE1 (HIRA) probe was normal; however, chromosomal microarray identified a ~737 kb heterozygous loss between LCR22B-D. Subsequently, the same deletion was identified in the mother, which included CRKL and 19 other genes but excluded HIRA and TBX1, the typical candidate genes for 22q11.2DS pathogenesis. This case explores how loss of CRKL may contribute to immune dysregulation, as seen in the multiple severe autoimmune phenotypes of the mother, and FGR. Our experience confirms the importance of thorough workup in individuals with reduced penetrance of 22q11.2 DS features or atypical clinical presentations.
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Affiliation(s)
- Isabella Lin
- David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA
| | - Yalda Afshar
- David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA.,Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of California Los Angeles, Los Angeles, California, USA
| | - Jeffrey Goldstein
- Pathology and Laboratory Medicine, UCLA Center for Health Sciences, Los Angeles, California, USA
| | - Jennifer Grossman
- David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA.,Division of Rheumatology, Department of Medicine, University of California Los Angeles, California, USA
| | - Wayne W Grody
- David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, USA.,Pathology and Laboratory Medicine, UCLA Center for Health Sciences, Los Angeles, California, USA.,Department of Human Genetics, University of California Los Angeles, Los Angeles, California, USA
| | - Fabiola Quintero-Rivera
- Departments of Pathology and Laboratory Medicine and Pediatrics, Division of Genetic and Genomic Medicine, University of California, Irvine, California, USA
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