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Oscorbin IP, Gordukova MA, Davydova NV, Zinovieva NV, Kovzel EF, Andries L, Kudlay DA, Filipenko ML. Multiplex droplet digital PCR for 22q11.2 microdeletions screening and DiGeorge syndrome diagnostics. Clin Chim Acta 2024; 563:119903. [PMID: 39127298 DOI: 10.1016/j.cca.2024.119903] [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: 05/31/2024] [Revised: 08/01/2024] [Accepted: 08/04/2024] [Indexed: 08/12/2024]
Abstract
BACKGROUND AND AIMS DiGeorge syndrome (DGS) is a genetic disorder manifesting in polymorphic symptoms related to developmental abnormalities of various organs including thymus. DGS is caused by microdeletions in the 22q11.2 region between several low copy repeats (LCR) occurring in approximately 1 in 4000 live births. Diagnosis of DGS relies on phenotypic examination, qPCR, ultrasound, FISH, MLPA and NGS which can be relatively inaccurate, time-consuming, and costly. MATERIALS AND METHODS A novel multiplex droplet digital PCR (ddPCR) assay was designed, optimized and validated for detection and mapping 22q11.2 microdeletions by simultaneous amplification of three targets - TUPLE1, ZNF74, D22S936 - within the deletion areas and one reference target - RPP30 - as an internal control. RESULTS The assay reliable identified microdeletions when the template concentration was >32 copies per reaction and successfully detected LCR22A-B, LCR22A-C, LCR22A-D, and LCR22B-C deletions in clinical samples from 153 patients with signs of immunodeficiency. In patients with the microdeletions, flow cytometry detected a significant increase in B-cell and natural killer cell counts and percentages, while T-cell percentages and T-cell receptor excision circle (TREC) numbers decreased. CONCLUSION The designed ddPCR assay is suitable for diagnosing DGS using whole blood and blood spots.
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Affiliation(s)
- Igor Petrovich Oscorbin
- Laboratory of Pharmacogenomics, The Institute of Chemical Biology and Fundamental Medicine of the Siberian Branch of the Russian Academy of Sciences (ICBFM SB RAS), Novosibirsk 630090, Russia.
| | | | | | | | - Elena Fedorovna Kovzel
- Clinical Immunology, Allergology, Pulmonology Program, Corporate Fund "University Medical Center" of Nazarbayev University, Astana, Kazakhstan
| | - Lucia Andries
- Laboratory of Clinical Immunology and Allergology, Nicolae Testemitanu State University of Medicine and Pharmacy of the Republic of Moldova, Chișinău, Moldova
| | - Dmitry Anatolyevich Kudlay
- The Department of Pharmacology, Faculty of Medicine, I.M. Sechenov First Moscow State Medical University, Pogodinskaya St. 1, Moscow 119991, Russia
| | - Maxim Leonidovich Filipenko
- Laboratory of Pharmacogenomics, The Institute of Chemical Biology and Fundamental Medicine of the Siberian Branch of the Russian Academy of Sciences (ICBFM SB RAS), Novosibirsk 630090, Russia
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Prenatal Screening and Diagnostic Considerations for 22q11.2 Microdeletions. Genes (Basel) 2023; 14:genes14010160. [PMID: 36672900 PMCID: PMC9858737 DOI: 10.3390/genes14010160] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/23/2022] [Accepted: 12/24/2022] [Indexed: 01/11/2023] Open
Abstract
Diagnosis of a chromosome 22q11.2 microdeletion and its associated deletion syndrome (22q11.2DS) is optimally made early. We reviewed the available literature to provide contemporary guidance and recommendations related to the prenatal period. Indications for prenatal diagnostic testing include a parent or child with the 22q11.2 microdeletion or suggestive prenatal screening results. Definitive diagnosis by genetic testing of chorionic villi or amniocytes using a chromosomal microarray will detect clinically relevant microdeletions. Screening options include noninvasive prenatal screening (NIPS) and imaging. The potential benefits and limitations of each screening method should be clearly conveyed. NIPS, a genetic option available from 10 weeks gestational age, has a 70-83% detection rate and a 40-50% PPV for most associated 22q11.2 microdeletions. Prenatal imaging, usually by ultrasound, can detect several physical features associated with 22q11.2DS. Findings vary, related to detection methods, gestational age, and relative specificity. Conotruncal cardiac anomalies are more strongly associated than skeletal, urinary tract, or other congenital anomalies such as thymic hypoplasia or cavum septi pellucidi dilatation. Among others, intrauterine growth restriction and polyhydramnios are additional associated, prenatally detectable signs. Preconception genetic counselling should be offered to males and females with 22q11.2DS, as there is a 50% risk of transmission in each pregnancy. A previous history of a de novo 22q11.2 microdeletion conveys a low risk of recurrence. Prenatal genetic counselling includes an offer of screening or diagnostic testing and discussion of results. The goal is to facilitate optimal perinatal care.
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Screening Method for 22q11 Deletion Syndrome Involving the Use of TaqMan qPCR for TBX1 in Patients with Conotruncal Congenital Heart Disease. CARDIOGENETICS 2022. [DOI: 10.3390/cardiogenetics12030024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
22q11.2 deletion syndrome is a phenotypic spectrum that encompasses DiGeorge syndrome (OMIM: 188400) and velocardiofacial syndrome (OMIM: 192430). It is caused by a 1.5–3.0 Mb hemizygous deletion of locus 22q11.2, which leads to characteristic facies, conotruncal cardiovascular malformations, velopharyngeal insufficiency, T-lymphocyte dysfunction due to thymic aplasia, and parathyroid hypoplasia, and, less frequently, neurological manifestations such as delayed psychomotor development or schizophrenia. This study aimed to describe a screening method for the diagnosis of 22q11.2 deletion syndrome in patients with Conotruncal Congenital Heart Disease (CCHD), using qPCR to detect the copy number of the TBX1 gene in a single DNA sample. A total of 23 patients were included; 21 with a biallelic prediction of the TBX1 copy number gene and 2 with a monoallelic prediction who were suspected to be positive and subjected to MLPA confirmation. One patient (4.34%) with truncus arteriosus CCHD was confirmed to have 22q11.2 deletion syndrome. We propose this approach as a possible newborn screening method for 22q11.2 deletion syndrome in CCHD patients.
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Blagojevic C, Heung T, Theriault M, Tomita-Mitchell A, Chakraborty P, Kernohan K, Bulman DE, Bassett AS. Estimate of the contemporary live-birth prevalence of recurrent 22q11.2 deletions: a cross-sectional analysis from population-based newborn screening. CMAJ Open 2021; 9:E802-E809. [PMID: 34404688 PMCID: PMC8373039 DOI: 10.9778/cmajo.20200294] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Although pathogenic 22q11.2 deletions are an important cause of developmental delays and lifelong disease burden, their variable and complex clinical expression contributes to under-recognition, delayed molecular diagnosis and uncertainty about prevalence. We sought to estimate the contemporary live-birth prevalence of typical 22q11.2 deletions using a population-based newborn screening sample and to examine data available for associated clinical features. METHODS Using DNA available from an unbiased sample of about 12% of all dried blood spots collected for newborn screening in Ontario between January 2017 and September 2018, we prospectively screened for 22q11.2 deletions using multiplex quantitative polymerase chain reaction assays and conducted independent confirmatory studies. We used cross-sectional analyses to compare available clinical and T-cell receptor excision circle (TREC, used in newborn screening for severe combined immunodeficiency) data between samples with and without 22q11.2 deletions. RESULTS The estimated minimum prevalence of 22q11.2 deletions was 1 in 2148 (4.7 per 10 000) live births (95% confidence interval [CI] 2.5 to 7.8 per 10 000), based on a total of 30 074 samples screened, with 14 having confirmed 22q11.2 deletions. Of term singletons, samples with 22q11.2 deletions had significantly younger median maternal age (25.5 v. 32.0 yr, difference -6.5 yr, 95% CI -7 to -2 yr), a greater proportion with small birth weight for gestational age (odds ratio 7.00, 95% CI 2.36 to 23.18) and lower median TREC levels (108.9 v. 602.5 copies/3 μL, p < 0.001). INTERPRETATION These results indicate that the 22q11.2 deletion syndrome is one of the most common of rare genetic conditions and may be associated with relatively younger maternal ages and with prenatal growth abnormalities. The findings support the public health importance of early - prenatal and neonatal - diagnosis that would enable prompt screening for and management of well-known actionable features associated with 22q11.2 deletions.
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Affiliation(s)
- Christina Blagojevic
- Clinical Genetics Research Program (Blagojevic, Heung, Bassett), Centre for Addiction and Mental Health; The Dalglish Family 22q Clinic (Blagojevic, Heung, Bassett), University Health Network; Department of Psychiatry (Bassett), University of Toronto, Toronto, Ont.; Children's Hospital of Eastern Ontario Research Institute (Theriault, Chakraborty, Kernohan, Bulman), University of Ottawa, Ottawa, Ont.; Division of Pediatric Cardiothoracic Surgery (Tomita-Mitchell), Department of Surgery, Medical College of Wisconsin, Herma Heart Institute, Milwaukee, Wisc
| | - Tracy Heung
- Clinical Genetics Research Program (Blagojevic, Heung, Bassett), Centre for Addiction and Mental Health; The Dalglish Family 22q Clinic (Blagojevic, Heung, Bassett), University Health Network; Department of Psychiatry (Bassett), University of Toronto, Toronto, Ont.; Children's Hospital of Eastern Ontario Research Institute (Theriault, Chakraborty, Kernohan, Bulman), University of Ottawa, Ottawa, Ont.; Division of Pediatric Cardiothoracic Surgery (Tomita-Mitchell), Department of Surgery, Medical College of Wisconsin, Herma Heart Institute, Milwaukee, Wisc
| | - Mylene Theriault
- Clinical Genetics Research Program (Blagojevic, Heung, Bassett), Centre for Addiction and Mental Health; The Dalglish Family 22q Clinic (Blagojevic, Heung, Bassett), University Health Network; Department of Psychiatry (Bassett), University of Toronto, Toronto, Ont.; Children's Hospital of Eastern Ontario Research Institute (Theriault, Chakraborty, Kernohan, Bulman), University of Ottawa, Ottawa, Ont.; Division of Pediatric Cardiothoracic Surgery (Tomita-Mitchell), Department of Surgery, Medical College of Wisconsin, Herma Heart Institute, Milwaukee, Wisc
| | - Aoy Tomita-Mitchell
- Clinical Genetics Research Program (Blagojevic, Heung, Bassett), Centre for Addiction and Mental Health; The Dalglish Family 22q Clinic (Blagojevic, Heung, Bassett), University Health Network; Department of Psychiatry (Bassett), University of Toronto, Toronto, Ont.; Children's Hospital of Eastern Ontario Research Institute (Theriault, Chakraborty, Kernohan, Bulman), University of Ottawa, Ottawa, Ont.; Division of Pediatric Cardiothoracic Surgery (Tomita-Mitchell), Department of Surgery, Medical College of Wisconsin, Herma Heart Institute, Milwaukee, Wisc
| | - Pranesh Chakraborty
- Clinical Genetics Research Program (Blagojevic, Heung, Bassett), Centre for Addiction and Mental Health; The Dalglish Family 22q Clinic (Blagojevic, Heung, Bassett), University Health Network; Department of Psychiatry (Bassett), University of Toronto, Toronto, Ont.; Children's Hospital of Eastern Ontario Research Institute (Theriault, Chakraborty, Kernohan, Bulman), University of Ottawa, Ottawa, Ont.; Division of Pediatric Cardiothoracic Surgery (Tomita-Mitchell), Department of Surgery, Medical College of Wisconsin, Herma Heart Institute, Milwaukee, Wisc
| | - Kristin Kernohan
- Clinical Genetics Research Program (Blagojevic, Heung, Bassett), Centre for Addiction and Mental Health; The Dalglish Family 22q Clinic (Blagojevic, Heung, Bassett), University Health Network; Department of Psychiatry (Bassett), University of Toronto, Toronto, Ont.; Children's Hospital of Eastern Ontario Research Institute (Theriault, Chakraborty, Kernohan, Bulman), University of Ottawa, Ottawa, Ont.; Division of Pediatric Cardiothoracic Surgery (Tomita-Mitchell), Department of Surgery, Medical College of Wisconsin, Herma Heart Institute, Milwaukee, Wisc
| | - Dennis E Bulman
- Clinical Genetics Research Program (Blagojevic, Heung, Bassett), Centre for Addiction and Mental Health; The Dalglish Family 22q Clinic (Blagojevic, Heung, Bassett), University Health Network; Department of Psychiatry (Bassett), University of Toronto, Toronto, Ont.; Children's Hospital of Eastern Ontario Research Institute (Theriault, Chakraborty, Kernohan, Bulman), University of Ottawa, Ottawa, Ont.; Division of Pediatric Cardiothoracic Surgery (Tomita-Mitchell), Department of Surgery, Medical College of Wisconsin, Herma Heart Institute, Milwaukee, Wisc
| | - Anne S Bassett
- Clinical Genetics Research Program (Blagojevic, Heung, Bassett), Centre for Addiction and Mental Health; The Dalglish Family 22q Clinic (Blagojevic, Heung, Bassett), University Health Network; Department of Psychiatry (Bassett), University of Toronto, Toronto, Ont.; Children's Hospital of Eastern Ontario Research Institute (Theriault, Chakraborty, Kernohan, Bulman), University of Ottawa, Ottawa, Ont.; Division of Pediatric Cardiothoracic Surgery (Tomita-Mitchell), Department of Surgery, Medical College of Wisconsin, Herma Heart Institute, Milwaukee, Wisc.
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Screening of 22q11.2DS Using Multiplex Ligation-Dependent Probe Amplification as an Alternative Diagnostic Method. BIOMED RESEARCH INTERNATIONAL 2021; 2020:6945730. [PMID: 33062692 PMCID: PMC7539069 DOI: 10.1155/2020/6945730] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 06/06/2020] [Indexed: 11/18/2022]
Abstract
Background The 22q11.2 deletion syndrome (22q11.2DS) is the most common form of deletion disorder in humans. Low copy repeats flanking the 22q11.2 region confers a substrate for nonallelic homologous recombination (NAHR) events leading to rearrangements which have been reported to be associated with highly variable and expansive phenotypes. The 22q11.2DS is reported as the most common genetic cause of congenital heart defects (CHDs). Methods A total of 42 patients with congenital heart defects, as confirmed by echocardiography, were recruited. Genetic molecular analysis using a fluorescence in situ hybridization (FISH) technique was conducted as part of routine 22q11.2DS screening, followed by multiplex ligation-dependent probe amplification (MLPA), which serves as a confirmatory test. Results Two of the 42 CHD cases (4.76%) indicated the presence of 22q11.2DS, and interestingly, both cases have conotruncal heart defects. In terms of concordance of techniques used, MLPA is superior since it can detect deletions within the 22q11.2 locus and outside of the typically deleted region (TDR) as well as duplications. Conclusion The incidence of 22q11.2DS among patients with CHD in the east coast of Malaysia is 0.047. MLPA is a scalable and affordable alternative molecular diagnostic method in the screening of 22q11.2DS and can be routinely applied for the diagnosis of deletion syndromes.
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Liao HC, Liao CH, Kao SM, Chiang CC, Chen YJ. Detecting 22q11.2 Deletion Syndrome in Newborns with Low T Cell Receptor Excision Circles from Severe Combined Immunodeficiency Screening. J Pediatr 2019; 204:219-224.e1. [PMID: 30268402 DOI: 10.1016/j.jpeds.2018.08.072] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 08/16/2018] [Accepted: 08/29/2018] [Indexed: 10/28/2022]
Abstract
OBJECTIVE Based on experiences and results from newborn screening for severe combined immunodeficiency (SCID), we evaluated the occurrence of chromosome 22q11.2 deletion syndrome (22q11.2DS) in newborns with different T cell receptor excision circles (TREC) results and established a second tier genetic test for 22q11.2DS. STUDY DESIGN Recalled dried blood spots from 486 newborns with TREC results <90 copies/uL were tested from the SCID newborn screening. Quantitative real-time polymerase chain reaction assay was used to detect the copy number of TBX1 and HIRA genes by simple DNA extraction method. Multiplex ligation dependent probe amplification was used for further confirmation. RESULTS Four hundred sixty-eight cases were considered negative because their haploid copy number of TBX1 and HIRA genes was >0.75. Eighteen cases with TBX1 and/or HIRA gene copy number <0.75 were suspected as positive, and 13 cases were further confirmed with 22q11.2DS. Detection rates of 22q11.2DS were 10.7% (6/56) in TREC <30 copies, 6.8% (9/132) in <50 TREC copies, 4.6% (12/260) in <70 TREC copies, and 2.7% (13/486) in <90 TREC copies. CONCLUSIONS 22q11.2DS detection can be incorporated into the second-tier assay in subjects with low TREC copies in SCID screening. The dried blood spot methods were feasible for 22q11.2DS newborn screening.
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Affiliation(s)
- Hsuan-Chieh Liao
- Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan; The Chinese Foundation of Health, Neonatal Screening Center, Taipei, Taiwan
| | - Chien-Hui Liao
- The Chinese Foundation of Health, Neonatal Screening Center, Taipei, Taiwan
| | - Shu-Min Kao
- The Chinese Foundation of Health, Neonatal Screening Center, Taipei, Taiwan
| | - Chuan-Chi Chiang
- The Chinese Foundation of Health, Neonatal Screening Center, Taipei, Taiwan
| | - Yann-Jang Chen
- Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan; Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan; Department of Pediatrics, Renai Branch, Taipei City Hospital, Taipei, Taiwan.
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McDonald-McGinn DM. 22q11.2 deletion syndrome: A tiny piece leading to a big picture. Am J Med Genet A 2018; 176:2055-2057. [PMID: 30380195 PMCID: PMC6472263 DOI: 10.1002/ajmg.a.40653] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Donna M. McDonald-McGinn
- 22q and You Center, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
- Clinical Genetics, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
- Section of Genetic Counseling, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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8
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Benn P, Iyengar S, Crowley TB, Zackai EH, Burrows EK, Moshkevich S, McDonald-McGinn DM, Sullivan KE, Demko Z. Pediatric healthcare costs for patients with 22q11.2 deletion syndrome. Mol Genet Genomic Med 2017; 5:631-638. [PMID: 29178641 PMCID: PMC6234953 DOI: 10.1002/mgg3.310] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 06/02/2017] [Accepted: 06/06/2017] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND The 22q11.2 deletion syndrome is a variably expressed disorder that can include cardiac, palate, and other physical abnormalities, immunodeficiency, and hypocalcemia. Because of the extreme variability in phenotype, there has been no available estimate of the total medical expenditure associated with the average case. METHODS We have developed a model to estimate the cost from the time of diagnosis to age 20. Costs were based on patients seen at a specialty center but also considered those components of care expected to have been provided by external healthcare facilities. Expense was based on billed medical charges extracted from the electronic medical billing system for all patients with a diagnosis of DiGeorge or velocardiofacial syndrome from 1993-2015. Expenditures included maternal prenatal care directly related to an affected pregnancy, molecular/cytogenetic diagnosis, consultations, surgery, and/or other treatment and management. Most mental health services (except inpatient), therapy related to cognitive, behavioral, speech, pharmacy, and nonmedical costs (special education, vocational, respite, lost earnings) were not included. RESULTS Data were available for 642 patients with 50.7% diagnosed prenatally or in the first year of life. The average cost for a patient was $727,178. Costs were highest for patients ascertained prenatally ($2,599,955) or in the first year of life ($1,043,096), those with cardiac abnormalities or referred for cardiac evaluation ($751,535), and patients with low T-cell counts ($1,382,222). CONCLUSION This study demonstrates that there are significant medical costs associated with 22q11.2 deletion syndrome.
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Affiliation(s)
- Peter Benn
- University of Connecticut Health Center, Farmington, Connecticut
| | | | - Terrence Blaine Crowley
- Children's Hospital of Philadelphia and the Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Elaine H Zackai
- Children's Hospital of Philadelphia and the Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Evanette K Burrows
- Children's Hospital of Philadelphia and the Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | | | - Donna M McDonald-McGinn
- Children's Hospital of Philadelphia and the Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
| | - Kathleen E Sullivan
- Children's Hospital of Philadelphia and the Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania
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Barry JC, Crowley TB, Jyonouchi S, Heimall J, Zackai EH, Sullivan KE, McDonald-McGinn DM. Identification of 22q11.2 Deletion Syndrome via Newborn Screening for Severe Combined Immunodeficiency. J Clin Immunol 2017; 37:476-485. [PMID: 28540525 DOI: 10.1007/s10875-017-0403-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 05/10/2017] [Indexed: 11/25/2022]
Abstract
PURPOSE Chromosome 22q11.2 deletion syndrome (22q11.2DS), the most common cause of DiGeorge syndrome, is quite variable. Neonatal diagnosis traditionally relies on recognition of classic features and cytogenetic testing, but many patients come to attention only following identification of later onset conditions, such as hypernasal speech due to palatal insufficiency and developmental and behavioral differences including speech delay, autism, and learning disabilities that would benefit from early interventions. Newborn screening (NBS) for severe combined immunodeficiency (SCID) is now identifying infants with 22q11.2DS due to T cell lymphopenia. Here, we report findings in such neonates, underscoring the efficacy of early diagnosis. METHODS A retrospective chart review of 1350 patients with 22q11.2DS evaluated at the Children's Hospital of Philadelphia identified 11 newborns with a positive NBS for SCID. RESULTS Five out of 11 would have been diagnosed with 22q11.2DS without NBS, whereas early identification of 22q11.2DS in 6/11 led to the diagnosis of significant associated features including hypocalcemia, congenital heart disease (CHD), and gastroesophageal reflux disease that may have gone unrecognized and therefore untreated. CONCLUSIONS Our findings support rapidly screening infants with a positive NBS for SCID, but without SCID, for 22q11.2DS even when typically associated features such as CHD are absent, particularly when B cells and NK cells are normal. Moreover, direct NBS for 22q11.2DS using multiplex qPCR would be equally, if not more, beneficial, as early identification of 22q11.2DS will obviate a protracted diagnostic odyssey while providing an opportunity for timely assessment and interventions as needed, even in the absence of T cell lymphopenia.
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Affiliation(s)
- Jessica C Barry
- The 22q and You Center, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Terrence Blaine Crowley
- The 22q and You Center, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Soma Jyonouchi
- The 22q and You Center, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Division of Allergy and Immunology, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Pediatrics, the Perelman School of Medicine at the University of Pennsylvania School of Medicine, 3401 Civic Center Boulevard, Philadelphia, PA, 19104, USA
| | - Jennifer Heimall
- The 22q and You Center, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Division of Allergy and Immunology, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Pediatrics, the Perelman School of Medicine at the University of Pennsylvania School of Medicine, 3401 Civic Center Boulevard, Philadelphia, PA, 19104, USA
| | - Elaine H Zackai
- The 22q and You Center, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Pediatrics, the Perelman School of Medicine at the University of Pennsylvania School of Medicine, 3401 Civic Center Boulevard, Philadelphia, PA, 19104, USA
| | - Kathleen E Sullivan
- The 22q and You Center, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Division of Allergy and Immunology, Children's Hospital of Philadelphia, Philadelphia, PA, USA
- Department of Pediatrics, the Perelman School of Medicine at the University of Pennsylvania School of Medicine, 3401 Civic Center Boulevard, Philadelphia, PA, 19104, USA
| | - Donna M McDonald-McGinn
- The 22q and You Center, Children's Hospital of Philadelphia, Philadelphia, PA, USA.
- Division of Human Genetics, Children's Hospital of Philadelphia, Philadelphia, PA, USA.
- Department of Pediatrics, the Perelman School of Medicine at the University of Pennsylvania School of Medicine, 3401 Civic Center Boulevard, Philadelphia, PA, 19104, USA.
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Dugoff L, Mennuti MT, McDonald-McGinn DM. The benefits and limitations of cell-free DNA screening for 22q11.2 deletion syndrome. Prenat Diagn 2016; 37:53-60. [DOI: 10.1002/pd.4864] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2016] [Revised: 06/14/2016] [Accepted: 06/16/2016] [Indexed: 12/24/2022]
Affiliation(s)
- Lorraine Dugoff
- Department of OB/GYN, Divisions of Reproductive Genetics and Maternal Fetal Medicine; University of Pennsylvania; Philadelphia PA USA
| | - Michael T. Mennuti
- Department of OB/GYN, Divisions of Reproductive Genetics and Maternal Fetal Medicine; University of Pennsylvania; Philadelphia PA USA
| | - Donna M. McDonald-McGinn
- Division of Human Genetics, 22q and You Center and Clinical Genetics Center, The Children's Hospital of Philadelphia, and the Department of Pediatrics; The Perelman School of Medicine of the University of Pennsylvania; Philadelphia PA USA
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Abstract
INTRODUCTION Newborn screening (NBS) for Severe combined immunodeficiency (SCID)/severe T cell lymphopenia (sTCL) is being increasingly used worldwide. AREAS COVERED In this manuscript we will discuss the following: 1) The rationale for screening newborns for SCID/sTCL; 2) The scientific basis for the use of the T cell receptor excision circle (TREC) assay in screening newborns for SCID/sTCL; 3) The published outcomes of current NBS programs. Expert commentary: 4) Some of the ethical dilemmas that occur when screening newborns for SCID. Finally, we will discuss the future directions for expanding NBS to include other primary immunodeficiencies.
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Affiliation(s)
- Becky J Buelow
- a Department of Pediatrics , Medical College of Wisconsin , Milwaukee , WI , USA
| | - James W Verbsky
- a Department of Pediatrics , Medical College of Wisconsin , Milwaukee , WI , USA.,b Department of Microbiology and Molecular Genetics , Medical College of Wisconsin and the Children's Research Institute, Medical College of Wisconsin , Milwaukee , WI , USA
| | - John M Routes
- a Department of Pediatrics , Medical College of Wisconsin , Milwaukee , WI , USA.,b Department of Microbiology and Molecular Genetics , Medical College of Wisconsin and the Children's Research Institute, Medical College of Wisconsin , Milwaukee , WI , USA
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12
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Brenner MK, Clarke S, Mahnke DK, Simpson P, Bercovitz RS, Tomita-Mitchell A, Mitchell ME, Newman DK. Effect of 22q11.2 deletion on bleeding and transfusion utilization in children with congenital heart disease undergoing cardiac surgery. Pediatr Res 2016; 79:318-24. [PMID: 26492284 PMCID: PMC5114022 DOI: 10.1038/pr.2015.216] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 07/31/2015] [Indexed: 01/10/2023]
Abstract
BACKGROUND Postsurgical bleeding causes significant morbidity and mortality in children undergoing surgery for congenital heart defects (CHD). 22q11.2 deletion syndrome (DS) is the second most common genetic risk factor for CHD. The deleted segment of chromosome 22q11.2 encompasses the gene encoding glycoprotein (GP) Ibβ, which is required for expression of the GPIb-V-IX complex on the platelet surface, where it functions as the receptor for von Willebrand factor (VWF). Binding of GPIb-V-IX to VWF is important for platelets to initiate hemostasis. It is not known whether hemizygosity for the gene encoding GPIbβ increases the risk for bleeding following cardiac surgery for patients with 22q11.2 DS. METHODS We performed a case-control study of 91 pediatric patients who underwent cardiac surgery with cardiopulmonary bypass from 2004 to 2012 at Children's Hospital of Wisconsin. RESULTS Patients with 22q11.2 DS had larger platelets and lower platelet counts, bled more excessively, and received more transfusion support with packed red blood cells in the early postoperative period relative to control patients. CONCLUSION Presurgical genetic testing for 22q11.2 DS may help to identify a subset of pediatric cardiac surgery patients who are at increased risk for excessive bleeding and who may require more transfusion support in the postoperative period.
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Affiliation(s)
- Michelle K Brenner
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, Wisconsin
| | - Shanelle Clarke
- Department of Pediatrics, Division of Critical Care and Cardiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Donna K Mahnke
- Department of Surgery, Division of Cardiothoracic Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Pippa Simpson
- Department of Pediatrics, Division of Quantitative Health Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Rachel S Bercovitz
- Medical Sciences Institute, BloodCenter of Wisconsin, Milwaukee, Wisconsin
| | - Aoy Tomita-Mitchell
- Department of Surgery, Division of Cardiothoracic Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Michael E Mitchell
- Department of Surgery, Division of Cardiothoracic Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin
- Department of Cardiothoracic Surgery, Children's Hospital of Wisconsin, Milwaukee, Wisconsin
| | - Debra K Newman
- Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, Wisconsin
- Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin
- Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, Milwaukee, Wisconsin
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13
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Kobrynski LJ, Yazdanpanah GK, Koontz D, Lee FK, Vogt RF. MALDI-TOF-MS Assay to Detect the Hemizygous 22q11.2 Deletion in DNA from Dried Blood Spots. Clin Chem 2015; 62:287-92. [PMID: 26585925 DOI: 10.1373/clinchem.2015.247148] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 10/26/2015] [Indexed: 12/24/2022]
Abstract
BACKGROUND A hemizygous deletion of 1.5-3 Mb in 22q11.2 causes a distinct clinical syndrome with variable congenital defects. Current diagnostic methods use fluorescent in situ hybridization (FISH) or comparative genomic hybridization by microarray to detect the deletion. Neither method is suitable for newborn screening (NBS), since they cannot be performed on dried blood spots (DBS). We developed a MALDI-TOF-MS assay that uses DBS to measure the hemizygous deletion of UFD1L, located within the 22q11.2 region. METHODS We used DBS from 54 affected patients, previously tested by FISH or microarray, and 100 cord blood samples to evaluate the performance of the MALDI-TOF-MS assay. With a single primer pair, a 97-base oligonucleotide within UFD1L was amplified, as was a sequence on chromosome 18 that differs by 2 nucleotides. A multiplexed, single-base extension reaction created allele-specific products for MALDI-TOF-MS detection. The products were spotted onto a silicon chip, and the height of the spectral peaks identified the relative amounts of target and reference gene. RESULTS The median ratio of the spectral peak for each UFD1L target:reference base was 0.96 and 0.99 for controls, compared with 0.35 and 0.53 for 22q11 deletion syndrome patients. There was 100% concordance between FISH/microarray and MALDI-TOF-MS in all patients with 22q11.2 deletion syndrome. CONCLUSIONS This method can be reliably performed with DBS and is suitable for high sample throughput. This assay may be considered for use in population-based NBS for 22q11.2 deletion.
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Affiliation(s)
- Lisa J Kobrynski
- Department of Pediatrics, Allergy and Immunology Section, Emory University School of Medicine, Atlanta, GA;
| | - Golriz K Yazdanpanah
- Newborn Screening Translational Research Initiative, CDC Foundation, Atlanta, GA
| | - Deborah Koontz
- Newborn Screening and Molecular Biology Branch, Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA
| | - Francis K Lee
- Newborn Screening and Molecular Biology Branch, Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA
| | - Robert F Vogt
- Newborn Screening and Molecular Biology Branch, Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA
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Abstract
22q11.2 deletion syndrome (22q11.2DS) is the most common chromosomal microdeletion disorder, estimated to result mainly from de novo non-homologous meiotic recombination events occurring in approximately 1 in every 1,000 fetuses. The first description in the English language of the constellation of findings now known to be due to this chromosomal difference was made in the 1960s in children with DiGeorge syndrome, who presented with the clinical triad of immunodeficiency, hypoparathyroidism and congenital heart disease. The syndrome is now known to have a heterogeneous presentation that includes multiple additional congenital anomalies and later-onset conditions, such as palatal, gastrointestinal and renal abnormalities, autoimmune disease, variable cognitive delays, behavioural phenotypes and psychiatric illness - all far extending the original description of DiGeorge syndrome. Management requires a multidisciplinary approach involving paediatrics, general medicine, surgery, psychiatry, psychology, interventional therapies (physical, occupational, speech, language and behavioural) and genetic counselling. Although common, lack of recognition of the condition and/or lack of familiarity with genetic testing methods, together with the wide variability of clinical presentation, delays diagnosis. Early diagnosis, preferably prenatally or neonatally, could improve outcomes, thus stressing the importance of universal screening. Equally important, 22q11.2DS has become a model for understanding rare and frequent congenital anomalies, medical conditions, psychiatric and developmental disorders, and may provide a platform to better understand these disorders while affording opportunities for translational strategies across the lifespan for both patients with 22q11.2DS and those with these associated features in the general population.
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Swillen A, McDonald-McGinn D. Developmental trajectories in 22q11.2 deletion. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2015; 169:172-81. [PMID: 25989227 DOI: 10.1002/ajmg.c.31435] [Citation(s) in RCA: 111] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Chromosome 22q11.2 deletion syndrome (22q11.2DS), a neurogenetic condition, is the most common microdeletion syndrome affecting 1 in 2,000-4,000 live births and involving haploinsufficiency of ∼50 genes resulting in a multisystem disorder. Phenotypic expression is highly variable and ranges from severe life-threatening conditions to only a few associated features. Most common medical problems include: congenital heart disease, in particular conotruncal anomalies; palatal abnormalities, most frequently velopharyngeal incompetence (VPI); immunodeficiency; hypocalcemia due to hypoparathyroidism; genitourinary anomalies; severe feeding/gastrointestinal differences; and subtle dysmorphic facial features. The neurocognitive profile is also highly variable, both between individuals and during the course of development. From infancy onward, motor delays (often with hypotonia) and speech/language deficits are commonly observed. During the preschool and primary school ages, learning difficulties are very common. The majority of patients with 22q11.2DS have an intellectual level that falls in the borderline range (IQ 70-84), and about one-third have mild to moderate intellectual disability. More severe levels of intellectual disability are uncommon in children and adolescents but are more frequent in adults. Individuals with 22q11.2DS are at an increased risk for developing several psychiatric disorders including attention deficit with hyperactivity disorder (ADHD), autism spectrum disorder (ASD), anxiety and mood disorders, and psychotic disorders and schizophrenia. In this review, we will focus on the developmental phenotypic transitions regarding cognitive development in 22q11.2DS from early preschool to adulthood, and on the changing behavioral/psychiatric phenotype across age, on a background of frequently complex medical conditions.
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16
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Dar N, Gothelf D, Korn D, Frisch A, Weizman A, Michaelovsky E, Carmel M, Yeshayahu Y, Dubnov-Raz G, Pessach IM, Simon AJ, Lev A, Somech R. Thymic and bone marrow output in individuals with 22q11.2 deletion syndrome. Pediatr Res 2015; 77:579-85. [PMID: 25580739 DOI: 10.1038/pr.2015.14] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 10/27/2014] [Indexed: 12/22/2022]
Abstract
BACKGROUND The 22q11.2 deletion syndrome (22q11.2DS) is a congenital multisystem anomaly characterized by typical facial features, palatal anomalies, congenital heart defects, hypocalcemia, immunodeficiency, and cognitive and neuropsychiatric symptoms. The aim of our study was to investigate T- and B-lymphocyte characteristics associated with 22q11.2DS. METHODS Seventy-five individuals with 22q11.2DS were tested for T and B lymphocytes by examination of T-cell receptor rearrangement excision circles (TRECs) and B-cell κ-deleting recombination excision circles (KRECs), respectively. RESULTS The 22q11.2DS individuals displayed low levels of TRECs, while exhibiting normal levels of KRECs. There was a significant positive correlation between TREC and KREC in the 22q11.2DS group, but not in controls. Both TREC and KREC levels showed a significant decrease with age and only TREC was low in 22q11.2DS individuals with recurrent infections. No difference in TREC levels was found between 22q11.2DS individuals who underwent heart surgery (with or without thymectomy) and those who did not. CONCLUSION T-cell immunodeficiency in 22q11.2DS includes low TREC levels, which may contribute to recurrent infections in individuals with this syndrome. A correlation between T- and B-cell abnormalities in 22q11.2DS was identified. The B-cell abnormalities could account for part of the immunological deficiency seen in 22q11.2DS.
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Affiliation(s)
- Nina Dar
- 1] Pediatric Department B and Immunology Services, Jeffrey Modell Foundation Center, Sheba Medical Center, Tel Hashomer, Israel [2] The Behavioral Neurogenetics Center, Sheba Medical Center, Tel Hashomer, Israel [3] Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel Hashomer, Affiliated to the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Doron Gothelf
- 1] The Behavioral Neurogenetics Center, Sheba Medical Center, Tel Hashomer, Israel [2] Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel Hashomer, Affiliated to the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - David Korn
- Pediatric Department B and Immunology Services, Jeffrey Modell Foundation Center, Sheba Medical Center, Tel Hashomer, Israel
| | - Amos Frisch
- Felsenstein Medical Research Center, Petah Tikva, Israel
| | - Abraham Weizman
- 1] Felsenstein Medical Research Center, Petah Tikva, Israel [2] Geha Mental Health Center, Petah Tikva, Israel
| | | | - Miri Carmel
- Felsenstein Medical Research Center, Petah Tikva, Israel
| | - Yonatan Yeshayahu
- 1] Pediatric Department B and Immunology Services, Jeffrey Modell Foundation Center, Sheba Medical Center, Tel Hashomer, Israel [2] Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel Hashomer, Affiliated to the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel [3] Pediatric Endocrinology Unit, Sheba Medical Center, Tel Hashomer, Israel
| | - Gal Dubnov-Raz
- 1] Pediatric Department B and Immunology Services, Jeffrey Modell Foundation Center, Sheba Medical Center, Tel Hashomer, Israel [2] Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel Hashomer, Affiliated to the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Itai M Pessach
- 1] Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel Hashomer, Affiliated to the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel [2] Department of Pediatric Critical Care, Sheba Medical Center, Tel Hashomer, Israel
| | - Amos J Simon
- Pediatric Department B and Immunology Services, Jeffrey Modell Foundation Center, Sheba Medical Center, Tel Hashomer, Israel
| | - Atar Lev
- Pediatric Department B and Immunology Services, Jeffrey Modell Foundation Center, Sheba Medical Center, Tel Hashomer, Israel
| | - Raz Somech
- 1] Pediatric Department B and Immunology Services, Jeffrey Modell Foundation Center, Sheba Medical Center, Tel Hashomer, Israel [2] Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel Hashomer, Affiliated to the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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Verbsky J, Routes J. Screening for and treatments of congenital immunodeficiency diseases. Clin Perinatol 2014; 41:1001-15. [PMID: 25459787 DOI: 10.1016/j.clp.2014.08.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Although newborn screening (NBS) for inborn errors of metabolism has been successfully utilized in the US for decades, only recently has this screening program expanded to include disorders of immunity. Severe combined immunodeficiency (SCID) became the first disorder of immunity to be screened on a population wide basis in 2008. While NBS for SCID has been successful, the implementation of population-based screening programs is not without controversy, and there remain barriers to the nationwide implementation of this test. In addition, as the program has progressed we have learned of new challenges in the management of newborns that fail this screen.
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Affiliation(s)
- James Verbsky
- Division of Rheumatology, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, USA.
| | - John Routes
- Division of Allergy/Immunology, Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, USA
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18
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Locke BA, Dasu T, Verbsky JW. Laboratory diagnosis of primary immunodeficiencies. Clin Rev Allergy Immunol 2014; 46:154-68. [PMID: 24569953 DOI: 10.1007/s12016-014-8412-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Primary immune deficiency disorders represent a highly heterogeneous group of disorders with an increased propensity to infections and other immune complications. A careful history to delineate the pattern of infectious organisms and other complications is important to guide the workup of these patients, but a focused laboratory evaluation is essential to the diagnosis of an underlying primary immunodeficiency. Initial workup of suspected immune deficiencies should include complete blood counts and serologic tests of immunoglobulin levels, vaccine titers, and complement levels, but these tests are often insufficient to make a diagnosis. Recent advancements in the understanding of the immune system have led to the development of novel immunologic assays to aid in the diagnosis of these disorders. Classically utilized to enumerate lymphocyte subsets, flow cytometric-based assays are increasingly utilized to test immune cell function (e.g., neutrophil oxidative burst, NK cytotoxicity), intracellular cytokine production (e.g., TH17 production), cellular signaling pathways (e.g., phosphor-STAT analysis), and protein expression (e.g., BTK, Foxp3). Genetic testing has similarly expanded greatly as more primary immune deficiencies are defined, and the use of mass sequencing technologies is leading to the identification of novel disorders. In order to utilize these complex assays in clinical care, one must have a firm understanding of the immunologic assay, how the results are interpreted, pitfalls in the assays, and how the test affects treatment decisions. This article will provide a systematic approach of the evaluation of a suspected primary immunodeficiency, as well as provide a comprehensive list of testing options and their results in the context of various disease processes.
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Affiliation(s)
- Bradley A Locke
- Department of Pediatrics, Division of Allergy and Clinical Immunology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
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19
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Abstract
Newborn screening (NBS) for severe T-cell lymphopenia/severe combined immunodeficiency using the T-cell receptor excision circle assay continues to expand in the USA and worldwide. Here, we will review why severe combined immunodeficiency is an excellent case for NBS, the outcomes of the first 6 years of screening, and dilemmas surrounding screening and management of infants detected by NBS. We will also discuss the future of NBS for primary immunodeficiencies.
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Affiliation(s)
- Becky J Buelow
- Department of Pediatrics, Medical College of Wisconsin, 9000 W Wisconsin Avenue, Suite 440, Milwaukee, WI, 53226, USA
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20
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Pretto D, Maar D, Yrigollen CM, Regan J, Tassone F. Screening newborn blood spots for 22q11.2 deletion syndrome using multiplex droplet digital PCR. Clin Chem 2014; 61:182-90. [PMID: 25388430 DOI: 10.1373/clinchem.2014.230086] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND The diagnosis of 22q11 deletion syndrome (22q11DS) is often delayed or missed due to the wide spectrum of clinical involvement ranging from mild to severe, often life-threatening conditions. A delayed diagnosis can lead to life-long health issues that could be ameliorated with early intervention and treatment. Owing to the high impact of 22q11DS on public health, propositions have been made to include 22q11DS in newborn screening panels; however, the method of choice for detecting 22q11DS, fluorescent in situ hybridization, requires specialized equipment and is cumbersome for most laboratories to implement as part of their routine screening. We sought to develop a new genetic screen for 22q11DS that is rapid, cost-effective, and easily used by laboratories currently performing newborn screening. METHODS We evaluated the accuracy of multiplex droplet digital PCR (ddPCR) in the detection of copy number of 22q11DS by screening samples from 26 patients with 22q11DS blindly intermixed with 1096 blood spot cards from the general population (total n = 1122). RESULTS Multiplex ddPCR correctly identified all 22q11DS samples and distinguished between 1.5- and 3-Mb deletions, suggesting the approach is sensitive and specific for the detection of 22q11DS. CONCLUSIONS These data demonstrate the utility of multiplex ddPCR for large-scale population-based studies that screen for 22q11DS. The use of samples from blood spot cards suggests that this approach has promise for newborn screening of 22q11DS, and potentially for other microdeletion syndromes, for which early detection can positively impact clinical outcome for those affected.
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Affiliation(s)
- Dalyir Pretto
- Department of Biochemistry and Molecular Medicine, UC Davis Medical Center, Sacramento, CA
| | - Dianna Maar
- Digital Biology Center, Bio-Rad Laboratories, Pleasanton, CA
| | - Carolyn M Yrigollen
- Department of Biochemistry and Molecular Medicine, UC Davis Medical Center, Sacramento, CA
| | - Jack Regan
- Digital Biology Center, Bio-Rad Laboratories, Pleasanton, CA
| | - Flora Tassone
- Department of Biochemistry and Molecular Medicine, UC Davis Medical Center, Sacramento, CA; MIND Institute, UC Davis Medical Center, Sacramento, CA.
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21
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Chen M, Yang YS, Shih JC, Lin WH, Lee DJ, Lin YS, Chou CH, Cameron AD, Ginsberg NA, Chen CA, Lee ML, Ma GC. Microdeletions/duplications involving TBX1 gene in fetuses with conotruncal heart defects which are negative for 22q11.2 deletion on fluorescence in-situ hybridization. ULTRASOUND IN OBSTETRICS & GYNECOLOGY : THE OFFICIAL JOURNAL OF THE INTERNATIONAL SOCIETY OF ULTRASOUND IN OBSTETRICS AND GYNECOLOGY 2014; 43:396-403. [PMID: 23828768 DOI: 10.1002/uog.12550] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 05/21/2013] [Accepted: 06/19/2013] [Indexed: 05/26/2023]
Abstract
OBJECTIVES Conotruncal heart defects (CTD) are associated with del22q11.2 syndrome, which is often diagnosed by fluorescence in-situ hybridization (FISH). However, in those negative for del22q11.2 on FISH, the etiology is usually obscure. We aimed to use high-resolution array comparative genomic hybridization (array CGH) to clarify the underlying genetic causes in these cases. METHODS In this retrospective study, fetal samples of amniocytes or fibroblasts, taken either for prenatal diagnosis by amniocentesis or for postnatal survey after termination of pregnancy, were obtained from 45 fetuses with CTD and were investigated by cytogenetic analysis including karyotyping and FISH for del22q11.2 syndrome. Eight fetuses with no findings on karyotyping and FISH were investigated further by array CGH, real-time quantitative polymerase chain reaction (qPCR) and Sanger sequencing of TBX1. RESULTS Array CGH revealed that three of the eight fetuses carried submicroscopic genomic imbalances. Of these, two cases showed similar small microdeletions/duplications in 22q11.2 (one 0.85 kb microdeletion and one 8.51 kb microduplication). The minimal shared region spanned exon 2 of TBX1, a candidate gene responsible for cardiovascular defects in del22q11.2 syndrome. In all eight cases, the array CGH results were confirmed by qPCR, and Sanger sequencing did not detect other molecular pathologies. CONCLUSION Our findings indicate an association between TBX1 variations and fetal CTD. The results also demonstrate the power of array CGH to further scrutinize the critical gene(s) of del22q11.2 syndrome responsible for heart defects. Array CGH apparently has diagnostic sensitivity superior to that of FISH in fetuses with CTD associated with del22q11.2 (and dup22q11.2) syndrome.
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Affiliation(s)
- M Chen
- Department of Genomic Medicine, Changhua Christian Hospital, Changhua, Taiwan; Department of Obstetrics and Gynecology, Changhua Christian Hospital, Changhua, Taiwan; Department of Obstetrics and Gynecology, College of Medicine and Hospital, National Taiwan University, Taipei, Taiwan; Department of Life Sciences, Tunghai University, Taichung, Taiwan; Department of Obstetrics and Gynecology, Chung Shan Medical University, Taichung, Taiwan
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22
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Lingman Framme J, Borte S, von Döbeln U, Hammarström L, Oskarsdóttir S. Retrospective analysis of TREC based newborn screening results and clinical phenotypes in infants with the 22q11 deletion syndrome. J Clin Immunol 2014; 34:514-9. [PMID: 24610337 DOI: 10.1007/s10875-014-0002-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 02/17/2014] [Indexed: 10/25/2022]
Abstract
PURPOSE Population-based newborn screening using T-cell receptor excision circles (TREC) identifies infants with severe T-lymphopenia, seen in severe combined immunodeficiencies (SCID), but also infants with the 22q11 deletion syndrome (22q11DS). Methods for analysis of kappa-deleting recombination excision circles (KREC) help identifying infants with B-lymphopenia. We aimed to evaluate the occurrence of abnormal TREC or KREC newborn screening results in 22q11DS patients and assessed the clinical relevance of abnormal screening reports. METHODS Simultaneous TREC and KREC analysis was performed on stored original Guthrie cards. Patients with abnormal screening reports were compared to patients with normal reports, regarding lymphocyte counts and clinical severity, obtained by retrospective analysis of medical charts. RESULTS Of 48 included patients, nine (19 %) had abnormal TREC copy numbers. All 22q11DS patients with abnormal TRECs had CD3+ T-lymphopenia at the time of diagnosis, but only one patient had the complete DiGeorge syndrome. Identified 22q11DS patients with abnormal TREC copy numbers showed significantly lower CD8+ T-lymphocytes at time-of-diagnosis and were significantly more prone to viral infections, compared to 22q11DS patients with normal TREC copy numbers. All 22q11DS patients showed KREC copies within the normal range. CONCLUSIONS In this retrospective study a high proportion of 22q11DS patients were identified by TREC-based newborn screening. Although only one of them had the complete DiGeorge syndrome with no T-lymphocytes, all of them had T-lymphopenia and most of them had recurrent viral infections, as well as other medical problems, warranting early recognition of the syndrome.
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Affiliation(s)
- Jenny Lingman Framme
- Department of Pediatrics, Halland Hospital Halmstad, S-301 85, Halmstad, Sweden,
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23
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Michaelovsky E, Frisch A, Carmel M, Patya M, Zarchi O, Green T, Basel-Vanagaite L, Weizman A, Gothelf D. Genotype-phenotype correlation in 22q11.2 deletion syndrome. BMC MEDICAL GENETICS 2012; 13:122. [PMID: 23245648 PMCID: PMC3548696 DOI: 10.1186/1471-2350-13-122] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Accepted: 12/10/2012] [Indexed: 12/31/2022]
Abstract
BACKGROUND The 22q11.2 deletion syndrome (22q11.2DS) is caused by hemizygous microdeletions on chromosome 22q11.2 with highly variable physical and neuropsychiatric manifestations. We explored the genotype-phenotype relationship in a relatively large 22q11.2DS cohort treated and monitored in our clinic using comprehensive clinical evaluation and detailed molecular characterization of the deletion. METHODS Molecular analyses in 142 subjects with 22q11.2DS features were performed by FISH and MLPA methods. Participants underwent clinical assessment of physical symptoms and structured psychiatric and cognitive evaluation. RESULTS Deletions were found in 110 individuals including one with an atypical nested distal deletion which was missed by the FISH test. Most subjects (88.2%) carried the 3Mb typically deleted region and 11.8% carried 4 types of deletions differing in size and location. No statistically significant genotype-phenotype correlations were found between deletion type and clinical data although some differences in hypocalcemia and cardiovascular anomalies were noted.Analysis of the patient with the distal nested deletion suggested a redundancy of genes causing the physical and neuropsychiatric phenotype in 22q11.2DS and indicating that the psychiatric and cognitive trajectories may be governed by different genes. CONCLUSIONS MLPA is a useful and affordable molecular method combining accurate diagnosis and detailed deletion characterization. Variations in deletion type and clinical manifestations impede the detection of significant differences in samples of moderate size, but analysis of individuals with unique deletions may provide insight into the underlying biological mechanisms.Future genotype-phenotype studies should involve large multicenter collaborations employing uniform clinical standards and high-resolution molecular methods.
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Borte S, Wang N, Oskarsdóttir S, von Döbeln U, Hammarström L. Newborn screening for primary immunodeficiencies: beyond SCID and XLA. Ann N Y Acad Sci 2012; 1246:118-30. [PMID: 22236436 DOI: 10.1111/j.1749-6632.2011.06350.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Primary immunodeficiencies (PID) encompass more than 250 disease entities, including phagocytic disorders, complement deficiencies, T cell defects, and antibody deficiencies. While differing in clinical severity, early diagnosis and treatment is of considerable importance for all forms of PID to prevent organ damage and life-threatening infections. During the past few years, neonatal screening assays have been developed to detect diseases hallmarked by the absence of T or B lymphocytes, classically seen in severe combined immunodeficiencies (SCID) and X-linked agammaglobulinemia (XLA). As described in this review, a reduction or lack of T and B cells in newborns is also frequently found in several other forms of PID, requiring supplemental investigation and involving the development of additional technical platforms in order to help classify abnormal screening results.
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Affiliation(s)
- Stephan Borte
- Division of Clinical Immunology and Transfusion Medicine, Department of Laboratory Medicine, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden
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25
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Accetta Pedersen DJ, Verbsky J, Routes JM. Screening newborns for primary T-cell immunodeficiencies: consensus and controversy. Expert Rev Clin Immunol 2012; 7:761-8. [PMID: 22014017 DOI: 10.1586/eci.11.25] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Newborn screening for early identification of T-cell lymphopenia and severe combined immunodeficiency has recently been recommended as an addition to the newborn screening programs in all states. This article will review the evidence supporting the use of this newborn screening test, and will outline the barriers to nationwide implementation, which include issues specific to this test and controversies regarding newborn screening in general.
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Affiliation(s)
- Deborah J Accetta Pedersen
- Department of Pediatrics, Medical College of Wisconsin and Children's Research Institute, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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26
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Tomita-Mitchell A, Mahnke DK, Struble CA, Tuffnell ME, Stamm KD, Hidestrand M, Harris SE, Goetsch MA, Simpson PM, Bick DP, Broeckel U, Pelech AN, Tweddell JS, Mitchell ME. Human gene copy number spectra analysis in congenital heart malformations. Physiol Genomics 2012; 44:518-41. [PMID: 22318994 DOI: 10.1152/physiolgenomics.00013.2012] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The clinical significance of copy number variants (CNVs) in congenital heart disease (CHD) continues to be a challenge. Although CNVs including genes can confer disease risk, relationships between gene dosage and phenotype are still being defined. Our goal was to perform a quantitative analysis of CNVs involving 100 well-defined CHD risk genes identified through previously published human association studies in subjects with anatomically defined cardiac malformations. A novel analytical approach permitting CNV gene frequency "spectra" to be computed over prespecified regions to determine phenotype-gene dosage relationships was employed. CNVs in subjects with CHD (n = 945), subphenotyped into 40 groups and verified in accordance with the European Paediatric Cardiac Code, were compared with two control groups, a disease-free cohort (n = 2,026) and a population with coronary artery disease (n = 880). Gains (≥200 kb) and losses (≥100 kb) were determined over 100 CHD risk genes and compared using a Barnard exact test. Six subphenotypes showed significant enrichment (P ≤ 0.05), including aortic stenosis (valvar), atrioventricular canal (partial), atrioventricular septal defect with tetralogy of Fallot, subaortic stenosis, tetralogy of Fallot, and truncus arteriosus. Furthermore, CNV gene frequency spectra were enriched (P ≤ 0.05) for losses at: FKBP6, ELN, GTF2IRD1, GATA4, CRKL, TBX1, ATRX, GPC3, BCOR, ZIC3, FLNA and MID1; and gains at: PRKAB2, FMO5, CHD1L, BCL9, ACP6, GJA5, HRAS, GATA6 and RUNX1. Of CHD subjects, 14% had causal chromosomal abnormalities, and 4.3% had likely causal (significantly enriched), large, rare CNVs. CNV frequency spectra combined with precision phenotyping may lead to increased molecular understanding of etiologic pathways.
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Affiliation(s)
- Aoy Tomita-Mitchell
- Department of Surgery, Division of Cardiothoracic Surgery, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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Abstract
Congenital heart disease is a major cause of morbidity and mortality throughout life. Mutations in numerous transcription factors have been identified in patients and families with some of the most common forms of cardiac malformations and arrhythmias. This review discusses transcription factor pathways known to be important for normal heart development and how abnormalities in these pathways have been linked to morphological and functional forms of congenital heart defects. A comprehensive, current list of known transcription factor mutations associated with congenital heart disease is provided, but the review focuses primarily on three key transcription factors, Nkx2-5, GATA4, and Tbx5, and their known biochemical and genetic partners. By understanding the interaction partners, transcriptional targets, and upstream activators of these core cardiac transcription factors, additional information about normal heart formation and further insight into genes and pathways affected in congenital heart disease should result.
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Affiliation(s)
- David J McCulley
- Cardiovascular Research Institute and Department of Biochemistry and Biophysics, University of California, San Francisco, California, USA
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Should 22q11 deletion be added to newborn screening panels? Am J Med Genet A 2011; 155A:fmvii-fmviii. [DOI: 10.1002/ajmg.a.33864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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