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Watanabe D, Okamoto N, Kobayashi Y, Suzuki H, Kato M, Saitoh S, Kanemura Y, Takenouchi T, Yamada M, Nakato D, Sato M, Tsunoda T, Kosaki K, Miya F. Biallelic structural variants in three patients with ERCC8-related Cockayne syndrome and a potential pitfall of copy number variation analysis. Sci Rep 2024; 14:19741. [PMID: 39187681 PMCID: PMC11347644 DOI: 10.1038/s41598-024-70831-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 08/21/2024] [Indexed: 08/28/2024] Open
Abstract
Cockayne syndrome (CS) is a rare autosomal recessive disorder caused by mutations in ERCC8 or ERCC6. Most pathogenic variants in ERCC8 are single nucleotide substitutions. Structural variants (SVs) have been reported in patients with ERCC8-related CS. However, comprehensive molecular detection, including SVs of ERCC8, in CS patients remains problematic. Herein, we present three Japanese patients with ERCC8-related CS in whom causative SVs were identified using whole-exome-based copy number variation (CNV) detection tools. One patient showed compound heterozygosity for a 259-kb deletion and a deletion of exon 4 which has previously been reported as an Asia-specific variant. The other two patients were homozygous for the same exon 4 deletion. The exon 4 deletion was detected only by the ExomeDepth software. Intrigued by the discrepancy in the detection capability of various tools for the SVs, we evaluated the analytic performance of four whole-exome-based CNV detection tools using an exome data set from 337 healthy individuals. A total of 1,278,141 exons were predicted as being affected by the 4 CNV tools. Interestingly 95.1% of these affected exons were detected by one tool alone. Thus, we expect that the use of multiple tools may improve the detection rate of SVs from aligned exome data.
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Affiliation(s)
- Daisuke Watanabe
- Center for Medical Genetics, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan
- Department of Pediatrics, Yamanashi University, Yamanashi, Japan
| | - Nobuhiko Okamoto
- Department of Medical Genetics, Osaka Women's and Children's Hospital, Osaka, Japan
| | - Yuichi Kobayashi
- Professional Development Center, Tokyo Medical and Dental University (TMDU), Tokyo, Japan
| | - Hisato Suzuki
- Center for Medical Genetics, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan
- Department of Clinical Medicine, Institute of Medicine, University of Tsukuba, Ibaraki, Japan
| | - Mitsuhiro Kato
- Department of Pediatrics, Showa University School of Medicine, Tokyo, Japan
- Epilepsy Medical Center, Showa University Hospital, Tokyo, Japan
| | - Shinji Saitoh
- Department of Pediatrics and Neonatology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Yonehiro Kanemura
- Department of Biomedical Research and Innovation, Institute for Clinical Research, NHO Osaka National Hospital, Osaka, Japan
- Department of Neurosurgery, NHO Osaka National Hospital, Osaka, Japan
| | - Toshiki Takenouchi
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
| | - Mamiko Yamada
- Center for Medical Genetics, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan
| | - Daisuke Nakato
- Center for Medical Genetics, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan
| | - Masayuki Sato
- Center for Medical Genetics, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan
| | - Tatsuhiko Tsunoda
- Laboratory for Medical Science Mathematics, Department of Biological Sciences, School of Science, The University of Tokyo, Tokyo, Japan
- Laboratory for Medical Science Mathematics, RIKEN Center for Integrative Medical Sciences, Yokohama, Japan
| | - Kenjiro Kosaki
- Center for Medical Genetics, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan
| | - Fuyuki Miya
- Center for Medical Genetics, Keio University School of Medicine, 35 Shinanomachi, Shinjuku, Tokyo, 160-8582, Japan.
- Innovative Human Resource Development Division, Institute of Education, Tokyo Medical and Dental University (TMDU), Tokyo, Japan.
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Kubota N, Takeda R, Kobayashi J, Hidaka E, Nishi E, Takano K, Wakui K. Reanalysis of Chromosomal Microarray Data Using a Smaller Copy Number Variant Call Threshold Identifies Four Cases with Heterozygous Multiexon Deletions of ARID1B, EHMT1, and FOXP1 Genes. Mol Syndromol 2023; 14:394-404. [PMID: 37901861 PMCID: PMC10601822 DOI: 10.1159/000530252] [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: 10/22/2022] [Accepted: 03/16/2023] [Indexed: 10/31/2023] Open
Abstract
Introduction Chromosomal microarray (CMA) is a highly accurate and established method for detecting copy number variations (CNVs) in clinical genetic testing. CNVs are important etiological factors for disorders such as intellectual disability, developmental delay, and multiple congenital anomalies. Recently developed analytical methods have facilitated the identification of smaller CNVs. Therefore, reanalyzing CMA data using a smaller CNV calling threshold may yield useful information. However, this method was left to the discretion of each institution. Methods We reanalyzed the CMA data of 131 patients using a smaller CNV call threshold: 50 kb 50 probes for gain and 25 kb 25 probes for loss. We interpreted the reanalyzed CNVs based on the most recently available information. In the reanalysis, we filtered the data using the Clinical Genome Resource dosage sensitivity gene list as an index to quickly and efficiently check morbid genes. Results The number of copy number loss was approximately 20 times greater, and copy number gain was approximately three times greater compared to those in the previous analysis. We detected new likely pathogenic CNVs in four participants: a 236.5 kb loss within ARID1B, a 50.6 kb loss including EHMT1, a 46.5 kb loss including EHMT1, and an 89.1 kb loss within the FOXP1 gene. Conclusion The method employed in this study is simple and effective for CMA data reanalysis using a smaller CNV call threshold. Thus, this method is efficient for both ongoing and repeated analyses. This study may stimulate further discussion of reanalysis methodology in clinical laboratories.
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Affiliation(s)
- Noriko Kubota
- Life Science Research Center, Nagano Children’s Hospital, Azumino, Japan
| | - Ryojun Takeda
- Life Science Research Center, Nagano Children’s Hospital, Azumino, Japan
- Division of Medical Genetics, Nagano Children’s Hospital, Azumino, Japan
| | - Jun Kobayashi
- Life Science Research Center, Nagano Children’s Hospital, Azumino, Japan
| | - Eiko Hidaka
- Life Science Research Center, Nagano Children’s Hospital, Azumino, Japan
| | - Eriko Nishi
- Division of Medical Genetics, Nagano Children’s Hospital, Azumino, Japan
| | - Kyoko Takano
- Division of Medical Genetics, Nagano Children’s Hospital, Azumino, Japan
- Department of Medical Genetics, Shinshu University School of Medicine, Matsumoto, Japan
- Center for Medical Genetics, Shinshu University Hospital, Matsumoto, Japan
| | - Keiko Wakui
- Life Science Research Center, Nagano Children’s Hospital, Azumino, Japan
- Department of Medical Genetics, Shinshu University School of Medicine, Matsumoto, Japan
- Center for Medical Genetics, Shinshu University Hospital, Matsumoto, Japan
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Yamada M, Tanito K, Suzuki H, Nakato D, Miya F, Takenouchi T, Kosaki K. Café-au-lait Spots and Cleft Palate: Not a Chance Association. Cleft Palate Craniofac J 2023:10556656231188205. [PMID: 37448313 DOI: 10.1177/10556656231188205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/15/2023] Open
Abstract
The recognition of syndromic forms of cleft palate is important for condition-specific management. Here, we report a patient with cleft palate, congenital heart disease, intellectual disability, and café-au-lait spots who had a deletion of chromosome 15q14. The identification of the precise breakpoints using a Nanopore-based long-read sequencer showed that the deletion spanned MEIS2 and SPRED1 loci. Cleft palate and café-au-lait spots can be ascribed to MEIS2 and SPRED1, respectively. Patients with cleft palate and café-au-lait spots should be encouraged to undergo a detailed genomic evaluation, including screening for a 15q14 deletion, to enable appropriate anticipatory medico-surgical management and genetic counseling.
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Affiliation(s)
- Mamiko Yamada
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | | | - Hisato Suzuki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Daisuke Nakato
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Fuyuki Miya
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Toshiki Takenouchi
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
| | - Kenjiro Kosaki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
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Suzuki H, Nozaki M, Yoshihashi H, Imagawa K, Kajikawa D, Yamada M, Yamaguchi Y, Morisada N, Eguchi M, Ohashi S, Ninomiya S, Seto T, Tokutomi T, Hida M, Toyoshima K, Kondo M, Inui A, Kurosawa K, Kosaki R, Ito Y, Okamoto N, Kosaki K, Takenouchi T. Genome Analysis in Sick Neonates and Infants: High-yield Phenotypes and Contribution of Small Copy Number Variations. J Pediatr 2022; 244:38-48.e1. [PMID: 35131284 DOI: 10.1016/j.jpeds.2022.01.033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 12/25/2021] [Accepted: 01/18/2022] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To delineate the diagnostic efficacy of medical exome, whole exome, and whole genome sequencing according to primary symptoms, the contribution of small copy number variations, and the impact of molecular diagnosis on clinical management. STUDY DESIGN This was a prospective study of 17 tertiary care centers in Japan, conducted between April 2019 and March 2021. Critically ill neonates and infants less than 6 months of age were recruited in neonatal intensive care units and in outpatient clinics. The patients underwent medical exome, whole exome, or whole genome sequencing as the first tier of testing. Patients with negative results after medical exome or whole exome sequencing subsequently underwent whole genome sequencing. The impact of molecular diagnosis on clinical management was evaluated through contacting primary care physicians. RESULTS Of the 85 patients, 41 (48%) had positive results. Based on the primary symptoms, patients with metabolic phenotypes had the highest diagnostic yield (67%, 4/6 patients), followed by renal (60%, 3/5 patients), and neurologic phenotypes (58%, 14/24 patients). Among them, 4 patients had pathogenic small copy number variations identified using whole genome sequencing. In the 41 patients with a molecular diagnosis, 20 (49%) had changes in clinical management. CONCLUSIONS Genome analysis for critically ill neonates and infants had a high diagnostic yield for metabolic, renal, and neurologic phenotypes. Small copy number variations detected using whole genome sequencing contributed to the overall molecular diagnosis in 5% of all the patients. The resulting molecular diagnoses had a significant impact on clinical management.
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Affiliation(s)
- Hisato Suzuki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Masatoshi Nozaki
- Department of Neonatal Medicine, Osaka Women's and Children's Hospital, Osaka, Japan
| | - Hiroshi Yoshihashi
- Department of Genetics, Tokyo Metropolitan Children's Medical Center, Tokyo, Japan
| | - Kazuo Imagawa
- Department of Child Health, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan
| | - Daigo Kajikawa
- Department of Neonatology, Ibaraki Children's Hospital, Ibaraki, Japan
| | - Mamiko Yamada
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Yu Yamaguchi
- Department of Clinical Genetics, Gunma Children's Medical Center, Gunma, Japan
| | - Naoya Morisada
- Department of Clinical Genetics, Hyogo Prefectural Kobe Children's Hospital, Hyogo, Japan
| | - Mayuko Eguchi
- Department of Neonatology, Tokyo Metropolitan Bokutoh Hospital, Tokyo, Japan
| | - Shoko Ohashi
- Department of Neonatology, Tokyo Metropolitan Ohtsuka Hospital, Tokyo, Japan
| | - Shinsuke Ninomiya
- Department of Clinical Genetics, Kurashiki Central Hospital, Okayama, Japan
| | - Toshiyuki Seto
- Department of Medical Genetics, Osaka City University Hospital, Osaka, Japan
| | - Tomoharu Tokutomi
- Department of Clinical Genetics, Iwate Medical University, Iwate, Japan
| | - Mariko Hida
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
| | - Katsuaki Toyoshima
- Department of Neonatology, Kanagawa Children's Medical Center, Kanagawa, Japan
| | - Masatoshi Kondo
- Department of Neonatology, Tokyo Metropolitan Children's Medical Center, Tokyo, Japan
| | - Ayano Inui
- Department of Pediatric Hepatology and Gastroenterology, Saiseikai Yokohama-shi Tobu Hospital, Kanagawa, Japan
| | - Kenji Kurosawa
- Division of Medical Genetics, Kanagawa Children's Medical Center, Kanagawa, Japan
| | - Rika Kosaki
- Division of Medical Genetics, National Center for Child Health and Development, Tokyo, Japan
| | - Yushi Ito
- Division of Neonatology, National Center for Child Health and Development, Tokyo, Japan
| | - Nobuhiko Okamoto
- Department of Medical Genetics, Osaka Women's and Children's Hospital, Osaka, Japan
| | - Kenjiro Kosaki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Toshiki Takenouchi
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan.
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Methods to Improve Molecular Diagnosis in Genomic Cold Cases in Pediatric Neurology. Genes (Basel) 2022; 13:genes13020333. [PMID: 35205378 PMCID: PMC8871714 DOI: 10.3390/genes13020333] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 02/06/2022] [Accepted: 02/07/2022] [Indexed: 02/04/2023] Open
Abstract
During the last decade, genetic testing has emerged as an important etiological diagnostic tool for Mendelian diseases, including pediatric neurological conditions. A genetic diagnosis has a considerable impact on disease management and treatment; however, many cases remain undiagnosed after applying standard diagnostic sequencing techniques. This review discusses various methods to improve the molecular diagnostic rates in these genomic cold cases. We discuss extended analysis methods to consider, non-Mendelian inheritance models, mosaicism, dual/multiple diagnoses, periodic re-analysis, artificial intelligence tools, and deep phenotyping, in addition to integrating various omics methods to improve variant prioritization. Last, novel genomic technologies, including long-read sequencing, artificial long-read sequencing, and optical genome mapping are discussed. In conclusion, a more comprehensive molecular analysis and a timely re-analysis of unsolved cases are imperative to improve diagnostic rates. In addition, our current understanding of the human genome is still limited due to restrictions in technologies. Novel technologies are now available that improve upon some of these limitations and can capture all human genomic variation more accurately. Last, we recommend a more routine implementation of high molecular weight DNA extraction methods that is coherent with the ability to use and/or optimally benefit from these novel genomic methods.
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Yamada M, Suzuki H, Shima T, Uehara T, Kosaki K. A patient with compound heterozygosity of SMPD4: Another example of utility of exome-based copy number analysis in autosomal recessive disorders. Am J Med Genet A 2021; 188:613-617. [PMID: 34622574 DOI: 10.1002/ajmg.a.62535] [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: 04/16/2021] [Accepted: 09/25/2021] [Indexed: 11/11/2022]
Abstract
For the efficient diagnosis of rare and undiagnosed diseases, the parallel detection of copy number variants (CNVs) and single nucleotide variants using exome analysis is required. Recently, our group reported the usefulness of a program called EXCAVATOR2, which screens for CNVs from aligned exome data in bam format. This method is expected to contribute to the identification of structural variants and to improve the diagnosis rate, especially for the diagnosis of autosomal recessive disease, when a conventional exome analysis identifies a pathogenic variant in one allele but not the other. Here we report a 2-year-old Japanese boy with an undiagnosed disease. He had severe neonatal asphyxia, severe intellectual disability, intractable seizures, cerebellar and brainstem hypoplasia and dysmorphic features including a prominent supraorbital ridge, thin upper lip, and prominent antihelix. An exome analysis reinforced with a copy number analysis using the EXCAVATOR2 method revealed that the patient had a hemizygous variant in chr2(GRCh37):g.130925108G>A, NM_017951.4 c.832C>T, p.(Arg278*) in SMPD4 that was derived from his father and a deletion of SMPD4 derived from his mother. The presence of the deletion spanning SMPD4 was confirmed by short-read and long-read whole-genome sequencing. The successful diagnosis of this reported patient demonstrates the diagnostic utility of EXCAVATOR2 and overcomes the weakness of exome analysis for the detection of autosomal recessive diseases in nonconsanguineous families, significantly impacting genetic counseling for family planning.
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Affiliation(s)
- Mamiko Yamada
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Hisato Suzuki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Taiki Shima
- Department of Pediatrics, Juntendo University Urayasu Hospital, Chiba, Japan
| | - Tomoko Uehara
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan.,Department of Pediatrics, Central Hospital, Aichi Developmental Disability Center, Aichi, Japan
| | - Kenjiro Kosaki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
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Han JY, Park J. A Recurrent De Novo Terminal Duplication of 14q32 in Korean Siblings Associated with Developmental Delay and Intellectual Disability, Growth Retardation, Facial Dysmorphism, and Cerebral Infarction: A Case Report and Literature Review. Genes (Basel) 2021; 12:1388. [PMID: 34573370 PMCID: PMC8472681 DOI: 10.3390/genes12091388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 08/30/2021] [Accepted: 09/01/2021] [Indexed: 11/16/2022] Open
Abstract
The terminal 14q32 duplication has been reported often in association with other cytogenetic abnormalities, and individuals with this specific duplication showed varying degrees of developmental delay/intellectual disability (DD/ID) and growth retardation (GR), and distinct facial dysmorphisms. Herein, based on the limited cases of terminal duplication of 14q32 known to date, we present new affected siblings presenting with DD/ID, GR, and facial dysmorphism, as well as cerebral infarction caused by recurrent de novo der(14)t(14;14)(p11.2;q32.1) leading to terminal duplication of 14q32. We used coverage analysis generated via duo exome sequencing, performed chromosomal microarray (CMA) as a confirmatory test, and compared our findings with those reported previously. Coverage analysis generated via duo exome sequencing revealed a 17.2 Mb heterozygous duplication at chromosome 14q32.11-q32.33 with a Z ratio ranging between 0.5 and 1 in the proband and her elder brother. As a complementary method, CMA established a terminal duplication described as the arr[hg19]14q32.11q32.33(90,043,558_107,258,824)x3 in the proband and her elder brother; however, the parents and other siblings showed normal karyotyping and no abnormal gain or loss of CMA results. Five candidate genes, BCL11B, CCNK, YY1, DYNC1H1, and PACS2, were associated with the clinical phenotypes in our cases. Although the parents had normal chromosomes, two affected cases carrying terminal duplication of 14q32 can be explained by gonadal mosaicism. Further studies are needed to establish the association between cerebrovascular events and terminal duplication of chromosome 14q32, including investigation into the cytogenetics of patients with precise clinical descriptions.
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Affiliation(s)
- Ji Yoon Han
- Department of Pediatrics, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea;
| | - Joonhong Park
- Department of Laboratory Medicine, Jeonbuk National University Medical School and Hospital, Jeonju 54907, Korea
- Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju 54907, Korea
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Yamada M, Suzuki H, Watanabe A, Uehara T, Takenouchi T, Mizuno S, Kosaki K. Role of chimeric transcript formation in the pathogenesis of birth defects. Congenit Anom (Kyoto) 2021; 61:76-81. [PMID: 33118233 DOI: 10.1111/cga.12400] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 09/30/2020] [Accepted: 10/26/2020] [Indexed: 12/16/2022]
Abstract
Chimeric transcripts are formed by chromosomal aberrations. Little is known about the role of chimeric transcripts in the pathogenesis of birth defects. We reanalyzed RNA-seq data in alignment map files from the peripheral blood of 56 patients in whom the diagnoses could not be confirmed by standard exome analysis and transcriptome analysis to screen for chimeric transcripts using a dedicated software, ChimPipe. Chimeric analysis led to a diagnosis in two of the 56 patients: (a) the first patient had a chimeric transcript spanning the causative gene ZEB2 and the GTDC1 gene in its neighboring locus. RNA-seq revealed reads spanning exon 5 of ZEB2 and exon 7 of GTDC1. Whole genome sequencing revealed a 436-kb deletion spanning intron 4 of ZEB2 and intron 7 of GTDC1 and the diagnosis of Mowat-Wilson syndrome was made. (b) The second patient had a chimeric transcript spanning the causative gene KCNK9 and the TRAPPC9 gene in its neighboring locus. RNA-seq revealed reads spanning exon 21 of TRAPPC9 and exon 1 of KCNK9. Whole genome sequencing revealed a 186-kb deletion spanning intron 20 of TRAPPC9 and intron 1 of KCNK9 in this patient. KCNK9 gene is a maternally expressed imprinted gene. The diagnosis of Birk-Barel syndrome was made. Thus, both patients had chimeric transcripts that were directly involved in the pathogenesis of the birth defects. The approach reported herein, of detecting chimeric transcripts from RNA-seq data, is unique in that the approach does not rely on any prior information on the presence of genomic deletion.
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Affiliation(s)
- Mamiko Yamada
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Hisato Suzuki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Akiko Watanabe
- Department of Pediatrics, Juntendo University Urayasu Hospital, Chiba, Japan
| | - Tomoko Uehara
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan.,Department of Pediatrics, Central Hospital, Aichi Developmental Disability Center, Aichi, Japan
| | - Toshiki Takenouchi
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
| | - Seiji Mizuno
- Department of Pediatrics, Central Hospital, Aichi Developmental Disability Center, Aichi, Japan
| | - Kenjiro Kosaki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
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9
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Maya I, Kahana S, Agmon-Fishman I, Klein C, Matar R, Berger R, Josefsberg SBY, Shohat M, Marom D, Basel-Salmon L, Sagi-Dain L. The phenotype of 15 cases with rare 8q24.13-q24.3 deletions-A new syndrome or still an enigma? Am J Med Genet A 2021; 185:1461-1467. [PMID: 33619900 DOI: 10.1002/ajmg.a.62131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 01/26/2021] [Accepted: 02/06/2021] [Indexed: 11/10/2022]
Abstract
Diagnosis of rare copy number variants (CNVs) with scarce literature evidence poses a major challenge for interpretation of the clinical significance of chromosomal microarray analysis (CMA) results, especially in the prenatal setting. Bioinformatic tools can be used to assist in this issue; however, this prediction can be imprecise. Our objective was to describe the phenotype of the rare copy number losses encompassing the 8q24.13-q24.3 locus, and to find common features in terms of genomic coordinates, gene content, and clinical phenotypic characteristics. Appropriate cases were retrieved using local databases of two largest Israeli centers performing CMA analysis. In addition, literature and public databases search was performed. Local database search yielded seven new patients with del (8)(q24.13q24.3) (one of these with an additional copy number variant). Literature and public databases search yielded eight additional patients. The cases showed high phenotypic variability, ranging from asymptomatic adults and fetuses with normal ultrasound to patients with autism/developmental delay (6/11 postnatal cases, 54.5%). No clear association was noted between the specific disease-causing/high-pLI gene content of the described del (8)(q24.13q24.3) to neurodevelopmental disorders, except for a possibly relevant locus encompassing the KCNQ3 gene. We present the challenges in classification of rare variants with limited clinical information. In such cases, genotype-phenotype correlation must be assessed with extra-caution and possibly using additional methods to assist the classification, especially in the prenatal setting.
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Affiliation(s)
- Idit Maya
- Recanati Genetics Institute, Beilinson Hospital, Rabin Medical Center, Petach Tikva, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Sarit Kahana
- Recanati Genetics Institute, Beilinson Hospital, Rabin Medical Center, Petach Tikva, Israel
| | - Ifaat Agmon-Fishman
- Recanati Genetics Institute, Beilinson Hospital, Rabin Medical Center, Petach Tikva, Israel
| | - Cochava Klein
- Recanati Genetics Institute, Beilinson Hospital, Rabin Medical Center, Petach Tikva, Israel
| | - Reut Matar
- Recanati Genetics Institute, Beilinson Hospital, Rabin Medical Center, Petach Tikva, Israel
| | - Racheli Berger
- Genetics Laboratory, Maccabi Health Services, Rehovot, Israel
| | | | - Mordechai Shohat
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Genetics Laboratory, Maccabi Health Services, Rehovot, Israel.,Bioinformatics Unit, Sheba Cancer Research Center, Sheba Medical Center, Tel Hashomer, Israel
| | - Daphna Marom
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Genetics Institute, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Lina Basel-Salmon
- Recanati Genetics Institute, Beilinson Hospital, Rabin Medical Center, Petach Tikva, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Pediatric Genetics Unit, Schneider Children's Medical Center of Israel, Felsenstein Medical Research Center, Rabin Medical Center, Petah Tikva, Israel
| | - Lena Sagi-Dain
- Genetics Institute, Carmel Medical Center, affiliated to the Ruth and Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
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10
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Suzuki H, Inaba M, Yamada M, Uehara T, Takenouchi T, Mizuno S, Kosaki K, Doi M. Biallelic loss of OTUD7A causes severe muscular hypotonia, intellectual disability, and seizures. Am J Med Genet A 2020; 185:1182-1186. [PMID: 33381903 DOI: 10.1002/ajmg.a.62054] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 11/13/2020] [Accepted: 12/02/2020] [Indexed: 02/02/2023]
Abstract
The heterozygous deletion of 15q13.3 is a recurrently observed microdeletion syndrome associated with a relatively mild phenotype including learning disability and language impairment. In contrast, the homozygous deletion of 15q13.3 is extremely rare and is associated with a much severer phenotype that includes epileptic encephalopathy, profound intellectual disability, and hypotonia. Which of the genes within the deleted interval is responsible for the more severe features when biallelically deleted is currently unknown. Here, we report a patient with profound hypotonia, severe intellectual disability, and seizures who had biallelic loss-of-function variants in OTUD7A: a 15q13.3 deletion including the OTUD7A locus, and a frameshift OTUD7A variant c.1125del, p.(Glu375Aspfs*11). Unexpectedly, both aberrations occurred de novo. Our experiment using Caenorhabditis elegans showed that worms carrying a corresponding homozygous variant in the homolog OTUB-2 exhibited weakened muscle contraction suggestive of aberrant neuromuscular transmission. We concluded that the biallelic complete loss of OTUD7A in humans represents a presumably new autosomal recessive disorder characterized by profound hypotonia, severe intellectual disability, and seizures.
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Affiliation(s)
- Hisato Suzuki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Mie Inaba
- Department of Clinical Genetics, Aichi Developmental Disability Center Central Hospital, Aichi, Japan
| | - Mamiko Yamada
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Tomoko Uehara
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan.,Department of Clinical Genetics, Aichi Developmental Disability Center Central Hospital, Aichi, Japan
| | - Toshiki Takenouchi
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
| | - Seiji Mizuno
- Department of Clinical Genetics, Aichi Developmental Disability Center Central Hospital, Aichi, Japan
| | - Kenjiro Kosaki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Motomichi Doi
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki, Japan
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