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Waldvogel SM, Posey JE, Goodell MA. Human embryonic genetic mosaicism and its effects on development and disease. Nat Rev Genet 2024; 25:698-714. [PMID: 38605218 PMCID: PMC11408116 DOI: 10.1038/s41576-024-00715-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/22/2024] [Indexed: 04/13/2024]
Abstract
Nearly every mammalian cell division is accompanied by a mutational event that becomes fixed in a daughter cell. When carried forward to additional cell progeny, a clone of variant cells can emerge. As a result, mammals are complex mosaics of clones that are genetically distinct from one another. Recent high-throughput sequencing studies have revealed that mosaicism is common, clone sizes often increase with age and specific variants can affect tissue function and disease development. Variants that are acquired during early embryogenesis are shared by multiple cell types and can affect numerous tissues. Within tissues, variant clones compete, which can result in their expansion or elimination. Embryonic mosaicism has clinical implications for genetic disease severity and transmission but is likely an under-recognized phenomenon. To better understand its implications for mosaic individuals, it is essential to leverage research tools that can elucidate the mechanisms by which expanded embryonic variants influence development and disease.
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Affiliation(s)
- Sarah M Waldvogel
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA
- Medical Scientist Training Program, Baylor College of Medicine, Houston, TX, USA
- Graduate Program in Cancer and Cell Biology, Baylor College of Medicine, Houston, TX, USA
| | - Jennifer E Posey
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Margaret A Goodell
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA.
- Graduate Program in Cancer and Cell Biology, Baylor College of Medicine, Houston, TX, USA.
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
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2
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Koga H, Takagi M, Teye K, Kuwahara-Sakurada F, Ishii N, Hamada T, Nakama T. Mosaicism for ATP2A2 Mutation and Mutant Allelic Fractions Detected by Droplet Digital PCR in Simple Segmental Darier Disease. Acta Derm Venereol 2023; 103:adv12337. [PMID: 37448212 PMCID: PMC10391532 DOI: 10.2340/actadv.v103.12337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 06/20/2023] [Indexed: 07/15/2023] Open
Abstract
Abstract is missing (Short communication)
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Affiliation(s)
- Hiroshi Koga
- Department of Dermatology, Kurume University School of Medicine, 67 Asahimachi, Kurume, Fukuoka 830-0011, Japan
| | - Marie Takagi
- Department of Dermatology, Kurume University School of Medicine, 67 Asahimachi, Kurume, Fukuoka 830-0011, Japan
| | | | - Fumi Kuwahara-Sakurada
- Department of Dermatology, Kurume University School of Medicine, 67 Asahimachi, Kurume, Fukuoka 830-0011, Japan
| | - Norito Ishii
- Department of Dermatology, Kurume University School of Medicine, 67 Asahimachi, Kurume, Fukuoka 830-0011, Japan
| | - Takahiro Hamada
- Department of Dermatology, Kurume University School of Medicine, 67 Asahimachi, Kurume, Fukuoka 830-0011, Japan.
| | - Takekuni Nakama
- Department of Dermatology, Kurume University School of Medicine, 67 Asahimachi, Kurume, Fukuoka 830-0011, Japan
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3
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Li X, Huang S, Wang G, Kang D, Han M, Wu X, Yang J, Zheng Q, Zhao C, Yuan Y, Dai P. Quantitative assessment of low-level parental mosaicism of SNVs and CNVs in Waardenburg syndrome. Hum Genet 2023; 142:419-430. [PMID: 36576601 DOI: 10.1007/s00439-022-02517-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 12/19/2022] [Indexed: 12/29/2022]
Abstract
Waardenburg syndrome (WS) is a rare inherited autosomal dominant disorder caused by SOX10, PAX3, MITF, EDNRB, EDN3, and SNAI2. A large burden of pathogenic de novo variants is present in patients with WS, which may be derived from parental mosaicism. Previously, we retrospectively analyzed 90 WS probands with family information. And the frequency of de novo events and parental mosaicism was preliminary investigated in our previous study. In this study, we further explored the occurrence of low-level parental mosaicism in 33 WS families with de novo variants and introduced our procedure of quantifying low-level mosaicism. Mosaic single nucleotide polymorphisms (SNPs) were validated by amplicon-based next-generation sequencing (NGS); copy-number variants (CNVs) were validated by droplet-digital polymerase chain reaction (ddPCR). Molecular validation of low-level mosaicism of WS-causing variants was performed in four families (12.1%, 4/33). These four mosaic variants, comprising three SNVs and one CNV, were identified in SOX10. The rate of parental mosaicism was 25% (4/16) in WS families with de novo SOX10 variants. The lowest allele ratio of a mosaic variant was 2.0% in parental saliva. These de novo WS cases were explained by parental mosaicism conferring an elevated recurrence risk in subsequent pregnancies of parents. Considering its importance in genetic counseling, low-level parental mosaicism should be systematically investigated by personalized sensitive testing. Amplicon-based NGS and ddPCR are recommended to detect and precisely quantify the mosaicism for SNPs and CNVs.
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Affiliation(s)
- Xiaohong Li
- College of Otolaryngology Head and Neck Surgery, Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, The Sixth Medical Center of Chinese PLA General Hospital, Chinese PLA Medical School, National Clinical Research Center for Otolaryngologic Diseases, #28 Fuxing Road, Beijing, 100853, China.,Department of Otorhinolaryngology Head and Neck Surgery, Key Laboratory for Pediatric Diseases of Otolaryngology-Head and Neck Surgery, National Center for Children's Health, Beijing Children's Hospital, Capital Medical University, Beijing, China
| | - Shasha Huang
- College of Otolaryngology Head and Neck Surgery, Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, The Sixth Medical Center of Chinese PLA General Hospital, Chinese PLA Medical School, National Clinical Research Center for Otolaryngologic Diseases, #28 Fuxing Road, Beijing, 100853, China
| | - Guojian Wang
- College of Otolaryngology Head and Neck Surgery, Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, The Sixth Medical Center of Chinese PLA General Hospital, Chinese PLA Medical School, National Clinical Research Center for Otolaryngologic Diseases, #28 Fuxing Road, Beijing, 100853, China
| | - Dongyang Kang
- College of Otolaryngology Head and Neck Surgery, Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, The Sixth Medical Center of Chinese PLA General Hospital, Chinese PLA Medical School, National Clinical Research Center for Otolaryngologic Diseases, #28 Fuxing Road, Beijing, 100853, China
| | - Mingyu Han
- College of Otolaryngology Head and Neck Surgery, Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, The Sixth Medical Center of Chinese PLA General Hospital, Chinese PLA Medical School, National Clinical Research Center for Otolaryngologic Diseases, #28 Fuxing Road, Beijing, 100853, China
| | - Xiedong Wu
- College of Otolaryngology Head and Neck Surgery, Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, The Sixth Medical Center of Chinese PLA General Hospital, Chinese PLA Medical School, National Clinical Research Center for Otolaryngologic Diseases, #28 Fuxing Road, Beijing, 100853, China
| | - Jinyuan Yang
- College of Otolaryngology Head and Neck Surgery, Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, The Sixth Medical Center of Chinese PLA General Hospital, Chinese PLA Medical School, National Clinical Research Center for Otolaryngologic Diseases, #28 Fuxing Road, Beijing, 100853, China
| | - Qiuchen Zheng
- College of Otolaryngology Head and Neck Surgery, Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, The Sixth Medical Center of Chinese PLA General Hospital, Chinese PLA Medical School, National Clinical Research Center for Otolaryngologic Diseases, #28 Fuxing Road, Beijing, 100853, China
| | - Chaoyue Zhao
- College of Otolaryngology Head and Neck Surgery, Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, The Sixth Medical Center of Chinese PLA General Hospital, Chinese PLA Medical School, National Clinical Research Center for Otolaryngologic Diseases, #28 Fuxing Road, Beijing, 100853, China
| | - Yongyi Yuan
- College of Otolaryngology Head and Neck Surgery, Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, The Sixth Medical Center of Chinese PLA General Hospital, Chinese PLA Medical School, National Clinical Research Center for Otolaryngologic Diseases, #28 Fuxing Road, Beijing, 100853, China.
| | - Pu Dai
- College of Otolaryngology Head and Neck Surgery, Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, The Sixth Medical Center of Chinese PLA General Hospital, Chinese PLA Medical School, National Clinical Research Center for Otolaryngologic Diseases, #28 Fuxing Road, Beijing, 100853, China.
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Abstract
Hundreds of different genetic causes of chronic kidney disease are now recognized, and while individually rare, taken together they are significant contributors to both adult and pediatric diseases. Traditional genetics approaches relied heavily on the identification of large families with multiple affected members and have been fundamental to the identification of genetic kidney diseases. With the increased utilization of massively parallel sequencing and improvements to genotype imputation, we can analyze rare variants in large cohorts of unrelated individuals, leading to personalized care for patients and significant research advancements. This review evaluates the contribution of rare disorders to patient care and the study of genetic kidney diseases and highlights key advancements that utilize new techniques to improve our ability to identify new gene-disease associations.
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Affiliation(s)
- Mark D Elliott
- Division of Nephrology, Department of Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA;
- Center for Precision Medicine and Genomics, Department of Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Institute for Genomic Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Hila Milo Rasouly
- Division of Nephrology, Department of Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA;
- Center for Precision Medicine and Genomics, Department of Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Ali G Gharavi
- Division of Nephrology, Department of Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA;
- Center for Precision Medicine and Genomics, Department of Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Institute for Genomic Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
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Caliskan Y, Lentine KL. Approach to genetic testing to optimize the safety of living donor transplantation in Alport syndrome spectrum. Pediatr Nephrol 2022; 37:1981-1994. [PMID: 35088158 DOI: 10.1007/s00467-022-05430-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 11/26/2021] [Accepted: 12/06/2021] [Indexed: 10/19/2022]
Abstract
Alport syndrome spectrum can be considered as a group of genetic diseases affecting the major basement membrane collagen type IV network in various organs including the ear, eye, and kidney. The living donor candidate evaluation is an ever-changing landscape. Recently, next-generation sequence (NGS) panels have become readily available and provide opportunities to genetically screen recipient and donor candidates for collagen network gene variants. In this review, our aim is to provide a comprehensive update on the role of genetic testing for the evaluation of potential living kidney donors to kidney candidates with Alport syndrome spectrum. We examine the utility of genetic testing in the evaluation of potential donors for recipients with Alport syndrome spectrum, and discuss risks and unresolved challenges. Suggested algorithms in the context of related and unrelated donation are offered. In contemporary practice, an approach to the evaluation of living donor candidates for transplant candidates with Alport syndrome spectrum can incorporate genetic testing in algorithms tailored for donor-recipient relationship status. Ongoing research is needed to inform optimal practice.
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Affiliation(s)
- Yasar Caliskan
- Saint Louis University Center for Abdominal Transplantation, 1201 S. Grand Blvd, St. Louis, MO, 63110, USA.
| | - Krista L Lentine
- Saint Louis University Center for Abdominal Transplantation, 1201 S. Grand Blvd, St. Louis, MO, 63110, USA
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Deng H, Zhang Y, Ding J, Wang F. Detection of Very Low-Level Somatic Mosaic COL4A5 Splicing Variant in Asymptomatic Female Using Droplet Digital PCR. Front Med (Lausanne) 2022; 9:847056. [PMID: 35360741 PMCID: PMC8963732 DOI: 10.3389/fmed.2022.847056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Accepted: 02/09/2022] [Indexed: 12/02/2022] Open
Abstract
Background Alport syndrome is a hereditary glomerulopathy featured by haematuria, proteinuria, and progressive renal failure. X-linked Alport syndrome (XLAS) due to COL4A5 disease-causing variants is the most common form. In the case of XLAS resulting from 10–18% presumed de novo COL4A5 disease-causing variants, there are only a few studies for mosaicism in the probands or parents. Very low-level (<1.0%) somatic mosaicism for COL4A5 disease-causing variants has not been published. Materials and Methods Chinese XLAS families with suspected parental mosaicism were enrolled in the present study to evaluate the forms of mosaicism, to offer more appropriate genetic counseling. PCR and direct sequencing were used to detect COL4A5 disease-causing variants harbored by the affected probands in parental multi-tissue DNAs (peripheral blood, urine sediments, saliva, hair), and droplet digital PCR (ddPCR) was used to quantify the mutant COL4A5 allelic fractions in parental different samples such as peripheral blood, saliva, and urine sediments. Results A Chinese asymptomatic female with suspected somatic and germline mosaicism was enrolled in the present study. She gave birth to two boys with XLAS caused by a hemizygous disease-causing variant c. 2245-1G>A in COL4A5 (NM_033380) intron 28, whereas this disease-causing variant was not detected in genomic DNA extracted from peripheral blood leukocytes in the woman using Sanger sequencing. She had multiple normal urine test results, and continuous linear immunofluorescence staining of α2 (IV) and α5 (IV) chains of skin tissue. Sanger sequencing demonstrated that COL4A5 disease-causing variant c. 2245-1G>A was not detected in her genomic DNAs isolated from urine sediments, saliva, and hair roots. Using ddPCR, the wild-type and mutant-type (c.2245-1G>A) COL4A5 was identified in the female's genomic DNAs isolated from peripheral blood, saliva, and urine sediments. The mutant allelic fractions in these tissues were 0.26% (peripheral blood), 0.73% (saliva), and 1.39% (urine), respectively. Conclusions Germline and very low-level somatic mosaicism for a COL4A5 splicing variant was detected in an asymptomatic female, which highlights that parental mosaicism should be excluded when a COL4A5 presumed de novo disease-causing variant is detected.
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Oliveira Netto AB, Brusius-Facchin AC, Leistner-Segal S, Kubaski F, Josahkian J, Giugliani R. Detection of Mosaic Variants in Mothers of MPS II Patients by Next Generation Sequencing. Front Mol Biosci 2021; 8:789350. [PMID: 34805285 PMCID: PMC8602069 DOI: 10.3389/fmolb.2021.789350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 10/22/2021] [Indexed: 11/13/2022] Open
Abstract
Mucopolysaccharidosis type II is an X-linked lysosomal storage disorder caused by mutations in the IDS gene that encodes the iduronate-2-sulfatase enzyme. The IDS gene is located on the long arm of the X-chromosome, comprising 9 exons, spanning approximately 24 kb. The analysis of carriers, in addition to detecting mutations in patients, is essential for genetic counseling, since the risk of recurrence for male children is 50%. Mosaicism is a well-known phenomenon described in many genetic disorders caused by a variety of mechanisms that occur when a mutation arises in the early development of an embryo. Sanger sequencing is limited in detecting somatic mosaicism and sequence change levels of less than 20% may be missed. The Next Generation Sequencing (NGS) has been increasingly used in diagnosis. It is a sensitive and fast method for the detection of somatic mosaicism. Compared to Sanger sequencing, which represents a cumulative signal, NGS technology analyzes the sequence of each DNA read in a sample. NGS might therefore facilitate the detection of mosaicism in mothers of MPS II patients. The aim of this study was to reanalyze, by NGS, all MPS II mothers that showed to be non-carriers by Sanger analysis. Twelve non-carriers were selected for the reanalysis on the Ion PGM and Ion Torrent S5 platform, using a custom panel that includes the IDS gene. Results were visualized in the Integrative Genomics Viewer (IGV). We were able to detected the presence of the variant previously found in the index case in three of the mothers, with frequencies ranging between 13 and 49% of the reads. These results suggest the possibility of mosaicism in the mothers. The use of a more sensitive technology for detecting low-level mosaic mutations is essential for accurate recurrence-risk estimates. In our study, the NGS analysis showed to be an effective methodology to detect the mosaic event.
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Affiliation(s)
- Alice Brinckmann Oliveira Netto
- Laboratory of Molecular Genetics, Medical Genetics Service, HCPA, Porto Alegre, Brazil.,Postgraduate Program in Genetics and Molecular Biology, UFRGS, Porto Alegre, Brazil
| | - Ana Carolina Brusius-Facchin
- Laboratory of Molecular Genetics, Medical Genetics Service, HCPA, Porto Alegre, Brazil.,National Institute on Population Medical Genetics, INAGEMP, Porto Alegre, Brazil.,BioDiscovery Laboratory, Experimental Research Center, HCPA, Porto Alegre, Brazil
| | - Sandra Leistner-Segal
- Laboratory of Molecular Genetics, Medical Genetics Service, HCPA, Porto Alegre, Brazil
| | - Francyne Kubaski
- Laboratory of Molecular Genetics, Medical Genetics Service, HCPA, Porto Alegre, Brazil.,Postgraduate Program in Genetics and Molecular Biology, UFRGS, Porto Alegre, Brazil.,National Institute on Population Medical Genetics, INAGEMP, Porto Alegre, Brazil.,BioDiscovery Laboratory, Experimental Research Center, HCPA, Porto Alegre, Brazil
| | - Juliana Josahkian
- Postgraduate Program in Genetics and Molecular Biology, UFRGS, Porto Alegre, Brazil.,Department of Clinical Medicine, Hospital Universitario de Santa Maria (HUSM), Santa Maria, Brazil
| | - Roberto Giugliani
- Laboratory of Molecular Genetics, Medical Genetics Service, HCPA, Porto Alegre, Brazil.,National Institute on Population Medical Genetics, INAGEMP, Porto Alegre, Brazil.,BioDiscovery Laboratory, Experimental Research Center, HCPA, Porto Alegre, Brazil.,Department of Genetics, UFRGS, Porto Alegre, Brazil
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Clinical Evaluation of a Novel Urine Collection Kit Using Filter Paper in Neonates: An Observational Study. CHILDREN-BASEL 2021; 8:children8070561. [PMID: 34209909 PMCID: PMC8304071 DOI: 10.3390/children8070561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 06/23/2021] [Accepted: 06/27/2021] [Indexed: 11/17/2022]
Abstract
Urine bags are commonly used to collect urine samples from neonates. However, the sample can be contaminated by stool, or detachment of the bag due to body movement can lead to failure of the collection. A qualitative urine collection kit containing ten filter papers of 3.2 mm diameter was developed and clinically verified among 138 neonates. During a single diaper change (approximately 3 h), the rate of urine collection was calculated. Urine collection was considered to be successful if any filter paper in the urine collection sheet turned from blue to white. Of the 127 neonates who passed urine, 122 had a change in the filter paper. The urine collection rate was 96%, with changes in all 10 filter papers observed in 98 neonates (80%). Urine collection rate was not influenced by sex (p = 1.00), age at collection (p = 0.72), preterm birth (p = 1.00), low birth weight (p = 0.92), or fecal contamination (p = 1.00). The incidence of dermatitis was not higher than in the group in which urine bags were used (urine collection kit: 2/68 [3%]; urine bag: 5/68 [7%]; p = 0.44). Novel urine collection kits using filter paper can collect samples from neonates safely and with a high probability of success.
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Wang G, Li X, Gao X, Su Y, Han M, Gao B, Guo C, Kang D, Huang S, Yuan Y, Dai P. Analysis of genotype-phenotype relationships in 90 Chinese probands with Waardenburg syndrome. Hum Genet 2021; 141:839-852. [PMID: 34142234 DOI: 10.1007/s00439-021-02301-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 06/08/2021] [Indexed: 12/31/2022]
Abstract
Waardenburg syndrome (WS) is a phenotypically and genetically heterogeneous disorder characterised by hearing loss and pigmentary abnormalities. We clarified the clinical and genetic features in 90 Chinese WS probands. Disease-causing variants were detected in 55 probands, for a molecular diagnosis rate of 61%, including cases related to PAX3 (14.4%), MITF (24.4%), and SOX10 (22.2%). Altogether, 48 variants were identified, including 44 single-nucleotide variants and 4 copy number variants. By parental genotyping, de novo variants were observed in 60% of probands and 15.4% of the de novo variation was associated with mosaicism. Statistical analyses revealed that brown freckles on the skin were more frequently seen in probands with MITF variants; patchy depigmented skin, asymmetric hearing loss, and white forelocks occurred more often in cases with PAX3 variants; and congenital inner ear malformations were more common and cochlear hypoplasia III was exclusively observed in those with SOX10 variants. In addition, we found that ranges of W-index values overlapped between WS probands with different genetic variants, and the use of the W-index as a tool for assessing dystopia canthorum may be problematic in Chinese. Herein, we report the spectrum of a cohort of WS probands and elucidate the relationship between genotype and phenotype.
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Affiliation(s)
- Guojian Wang
- Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, National Clinical Research Center for Otolaryngologic Diseases, College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, #28 Fuxing Road, Beijing, 100853, China
| | - Xiaohong Li
- Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, National Clinical Research Center for Otolaryngologic Diseases, College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, #28 Fuxing Road, Beijing, 100853, China.,Department of Otorhinolaryngology Head and Neck Surgery, National Center for Children's Health, Beijing Children's Hospital, Capital Medical University, Beijing, China.,Beijing Key Laboratory for Pediatric, Diseases of Otolaryngology-Head and Neck Surgery, Beijing, China
| | - Xue Gao
- Department of Otolaryngology, PLA Rocket Force Characteristic Medical Center, Beijing, China
| | - Yu Su
- Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, National Clinical Research Center for Otolaryngologic Diseases, College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, #28 Fuxing Road, Beijing, 100853, China
| | - Mingyu Han
- Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, National Clinical Research Center for Otolaryngologic Diseases, College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, #28 Fuxing Road, Beijing, 100853, China
| | - Bo Gao
- Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, National Clinical Research Center for Otolaryngologic Diseases, College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, #28 Fuxing Road, Beijing, 100853, China
| | - Chang Guo
- Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, National Clinical Research Center for Otolaryngologic Diseases, College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, #28 Fuxing Road, Beijing, 100853, China
| | - Dongyang Kang
- Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, National Clinical Research Center for Otolaryngologic Diseases, College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, #28 Fuxing Road, Beijing, 100853, China
| | - Shasha Huang
- Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, National Clinical Research Center for Otolaryngologic Diseases, College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, #28 Fuxing Road, Beijing, 100853, China.
| | - Yongyi Yuan
- Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, National Clinical Research Center for Otolaryngologic Diseases, College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, #28 Fuxing Road, Beijing, 100853, China.
| | - Pu Dai
- Key Lab of Hearing Impairment Science of Ministry of Education, Key Lab of Hearing Impairment Prevention and Treatment of Beijing, National Clinical Research Center for Otolaryngologic Diseases, College of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, #28 Fuxing Road, Beijing, 100853, China.
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10
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Detection of Cryptic Mosaicism in X-linked Alport Syndrome Prompts to Re-evaluate Living-donor Kidney Transplantation. Transplantation 2021; 104:2360-2364. [PMID: 31895869 DOI: 10.1097/tp.0000000000003104] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
BACKGROUND Alport syndrome is a hereditary nephropathy caused by mutations in collagen IV genes and characterized by ultrastructural lesions of the glomerular basement membrane. Some patients have a negative family history with apparently de novo mutations. Although somatic mosaicism has been postulated, as cryptic mosaicism cannot be detected from mutational screening on peripheral blood samples, cases in kidney-confined mosaic form have been missed. METHODS We report the case of a 24-year-old male patient with X-linked Alport syndrome diagnosis due to a COL4A5 pathogenic mutation (c.3334_3337dup [p.Gly1113Alafs25]). The same mutation had not been previously detected on a peripheral blood sample of maternal DNA. However, the mother, who was undertaking a clinical re-evaluation to take in consideration the possibility of a living-kidney transplantation, had experienced persistent microhematuria since the age of 10 years. RESULTS A next-generation sequencing approach performed on maternal DNA from both peripheral blood sample and urine-derived podocyte-lineage cells unmasked the COL4A5 mutation only in the podocyte-lineage cells. CONCLUSIONS This finding unveils an early postzygotic event which can explain both the renal involvement and germline mosaicism. It changes the inheritance risk for each pregnancy raising it to 50% and underlines the need for different clinical management in the mother. This seems to indicate that a case-by-case more cautious approach is needed with mother-to-son kidney transplants.
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11
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Helle OMB, Pedersen TH, Ousager LB, Thomassen M, Hertz JM. Low frequency of parental mosaicism in de novo COL4A5 mutations in X-linked Alport syndrome. Mol Genet Genomic Med 2020; 8:e1452. [PMID: 32812400 PMCID: PMC7549549 DOI: 10.1002/mgg3.1452] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 06/07/2020] [Accepted: 07/01/2020] [Indexed: 12/19/2022] Open
Abstract
Background Alport syndrome is a progressive hereditary kidney disease clinically presenting with haematuria, proteinuria, and early onset end‐stage renal disease, and often accompanied by hearing loss and ocular abnormalities. The inheritance is X‐linked in the majority of families and caused by sequence variants in the COL4A5 gene encoding the α5‐chain of type‐IV collagen. The proportion of de novo COL4A5 sequence variants in X‐linked Alport syndrome has been reported between 12 and 15% in previous studies. Methods In the present study we have systematically investigated the mosaic status of asymptomatic parents of six patients with X‐linked Alport syndrome using next‐generation sequencing of DNA extracted from different tissues. The deleterious COL4A5 sequence variants in these patients were previously assumed to be de novo, based on Sanger sequencing of the parents. Results A low‐grade (1%) parental mosaicism was detected in only one out of six families (17%). In addition, in one out of six families (17%), we found that the mutational event probably occurred postzygotic. Conclusion These findings highlight the importance of testing for mosaicism in unaffected parents of patients with sequence variants considered to be de novo, as it may have implications for the recurrence risk and thereby for the genetic counseling of the family.
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Affiliation(s)
- Ole Magnus Bjorgaas Helle
- Department of Clinical Genetics, Odense University Hospital, Odense, Denmark.,Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Torkild Høieggen Pedersen
- Department of Clinical Genetics, Odense University Hospital, Odense, Denmark.,Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Lilian Bomme Ousager
- Department of Clinical Genetics, Odense University Hospital, Odense, Denmark.,Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Mads Thomassen
- Department of Clinical Genetics, Odense University Hospital, Odense, Denmark.,Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Jens Michael Hertz
- Department of Clinical Genetics, Odense University Hospital, Odense, Denmark.,Department of Clinical Research, University of Southern Denmark, Odense, Denmark
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12
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Dai C, Cheng D, Li W, Zeng S, Lu G, Zhang Q. Identification of paternal germline mosaicism by MicroSeq and targeted next-generation sequencing. Mol Genet Genomic Med 2020; 8:e1394. [PMID: 32643877 PMCID: PMC7507370 DOI: 10.1002/mgg3.1394] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 05/26/2020] [Accepted: 06/08/2020] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Prezygotic de novo mutations may be inherited from parents with germline mosaicism and are often overlooked when the resulting phenotype affects only one child. We aimed to identify paternal germline mosaicism in an index family and provide a strategy to determine germline mosaicism.' METHODS Whole-exome sequencing was performed on an Alport syndrome-affected child. Variants were validated using Sanger sequencing in the pedigree analysis. An apparent de novo mutation was tested by next-generation sequencing (NGS) following chromosome microdissection of the mutant region (MicroSeq) to clarify its homologous chromosome source. Mosaic mutation in sperm samples was detected using targeted next-generation sequencing (TNGS). Self-prepared mosaic DNA samples of the 3% and 0.1% mutant fractions were used to evaluate the TNGS detection sensitivity. RESULTS Two novel heterozygous variants, maternally inherited c.1322delT (p.Ile441Thrfs*17) and the de novo mutation c.2939T>A (p.Leu980Ter), in the COL4A3 gene were discovered in the propositus. MicroSeq identified c.2939T>A in the paternal chromosome, which was in trans with c.1322delT. The frequency of c.2937A was 2.65% in the father's sperm sample. We also showed that a 500X depth coverage may detect a mosaic mutation with an allele frequency as low as 2%-3% using TNGS. CONCLUSION MicroSeq is a valuable tool to identify the allele source of de novo mutations in a single patient. TNGS can be used to assess the mosaic ratios of known sites. We provided a systematic algorithm to detect germinal mosaicism in a single patient. This algorithm may have implications for genetic and reproductive counseling on germline mosaicism.
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Affiliation(s)
- Congling Dai
- Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Science, Central South University, Hunan, China
| | - Dehua Cheng
- Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Science, Central South University, Hunan, China.,Reproductive and Genetic Hospital ofCITIC-Xiangya, Hunan, China
| | - Weina Li
- Reproductive and Genetic Hospital ofCITIC-Xiangya, Hunan, China
| | - Sicong Zeng
- Reproductive and Genetic Hospital ofCITIC-Xiangya, Hunan, China.,School of medicine, Hunan Normal University, Hunan, China
| | - Guangxiu Lu
- Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Science, Central South University, Hunan, China.,Reproductive and Genetic Hospital ofCITIC-Xiangya, Hunan, China.,School of medicine, Hunan Normal University, Hunan, China.,Hunan Guangxiu Hospital, Hunan, China
| | - Qianjun Zhang
- Institute of Reproductive and Stem Cell Engineering, School of Basic Medical Science, Central South University, Hunan, China.,Reproductive and Genetic Hospital ofCITIC-Xiangya, Hunan, China.,Hunan Guangxiu Hospital, Hunan, China
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13
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Aoto Y, Kise T, Nakanishi K, Nagano C, Horinouchi T, Yamamura T, Ishiko S, Sakakibara N, Shima Y, Morisada N, Iijima K, Nozu K. A case with somatic and germline mosaicism in COL4A5 detected by multiplex ligation-dependent probe amplification in X-linked Alport syndrome. CEN Case Rep 2020; 9:431-436. [PMID: 32621070 DOI: 10.1007/s13730-020-00503-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 06/28/2020] [Indexed: 01/19/2023] Open
Abstract
X-linked Alport syndrome (XLAS) is a progressive hereditary kidney disease caused by mutations in the COL4A5 gene encoding the type IV collagen α5 chain. To date, 11 cases having somatic mosaic variants in COL4A5 have been reported; however, all of them involved single-nucleotide variations (SNVs). Here, we report a female XLAS patient with somatic mosaicism identified by copy number variation (CNV) in COL4A5. The case was a 35-year-old female, the mother of the proband, whose only clinical symptom was hematuria. The proband, who was the son of this patient, was diagnosed with XLAS by gene testing, which showed a large hemizygous deletion from exon 3-51 in COL4A5 detected by next-generation sequencing and then confirmed by multiplex ligation-dependent probe amplification (MLPA). Then, MLPA analysis revealed that the female patient had the same deletion with only a 20% copy number reduction compared with a normal female control; she was thus diagnosed with XLAS with somatic mosaicism. CNVs in COL4A5 are relatively rare and, to the best of our knowledge, somatic mosaic variants with CNVs have never been reported. This case clearly featured a germline variant because the patient's son exhibited XLAS. This is thus the first case report on an XLAS patient having CNV in COL4A5 with somatic mosaicism. The obtained findings were very important for the genetic counseling of this family.
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Affiliation(s)
- Yuya Aoto
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan.
| | - Tomoo Kise
- Division of Pediatric Nephrology, Okinawa Prefectural Nanbu Medical Center, Children's Medical Center, 118-1 Arakawa, Haebaru-cho, Simajiri-gun, Okinawa, 901-1105, Japan
| | - Koichi Nakanishi
- Department of Pediatrics, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara-cho, Nakagami-gun, Okinawa, 903-0125, Japan
| | - China Nagano
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan
| | - Tomoko Horinouchi
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan
| | - Tomohiko Yamamura
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan
| | - Shinya Ishiko
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan
| | - Nana Sakakibara
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan
| | - Yuko Shima
- Department of Pediatrics, Wakayama Medical University, 811-1 Kimiidera, Wakayama, 641-8509, Japan
| | - Naoya Morisada
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan
| | - Kazumoto Iijima
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan
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14
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Savige J, Ariani F, Mari F, Bruttini M, Renieri A, Gross O, Deltas C, Flinter F, Ding J, Gale DP, Nagel M, Yau M, Shagam L, Torra R, Ars E, Hoefele J, Garosi G, Storey H. Expert consensus guidelines for the genetic diagnosis of Alport syndrome. Pediatr Nephrol 2019; 34:1175-1189. [PMID: 29987460 DOI: 10.1007/s00467-018-3985-4] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 02/22/2018] [Accepted: 05/10/2018] [Indexed: 12/16/2022]
Abstract
Recent expert guidelines recommend genetic testing for the diagnosis of Alport syndrome. Here, we describe current best practice and likely future developments. In individuals with suspected Alport syndrome, all three COL4A5, COL4A3 and COL4A4 genes should be examined for pathogenic variants, probably by high throughput-targeted next generation sequencing (NGS) technologies, with a customised panel for simultaneous testing of the three Alport genes. These techniques identify up to 95% of pathogenic COL4A variants. Where causative pathogenic variants cannot be demonstrated, the DNA should be examined for deletions or insertions by re-examining the NGS sequencing data or with multiplex ligation-dependent probe amplification (MLPA). These techniques identify a further 5% of variants, and the remaining few changes include deep intronic splicing variants or cases of somatic mosaicism. Where no pathogenic variants are found, the basis for the clinical diagnosis should be reviewed. Genes in which mutations produce similar clinical features to Alport syndrome (resulting in focal and segmental glomerulosclerosis, complement pathway disorders, MYH9-related disorders, etc.) should be examined. NGS approaches have identified novel combinations of pathogenic variants in Alport syndrome. Two variants, with one in COL4A3 and another in COL4A4, produce a more severe phenotype than an uncomplicated heterozygous change. NGS may also identify further coincidental pathogenic variants in genes for podocyte-expressed proteins that also modify the phenotype. Our understanding of the genetics of Alport syndrome is evolving rapidly, and both genetic and non-genetic factors are likely to contribute to the observed phenotypic variability.
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Affiliation(s)
- Judy Savige
- Department of Medicine, Melbourne and Northern Health, The University of Melbourne, Parkville, VIC, 3050, Australia.
| | | | | | | | | | - Oliver Gross
- Clinic of Nephrology and Rheumatology, University of Gottingen, Gottingen, Germany
| | | | - Frances Flinter
- Department of Clinical Genetics, Guys' and St Thomas' NHS Foundation Trust, London, UK
| | - Jie Ding
- Peking University First Hospital, Beijing, China
| | - Daniel P Gale
- Centre for Nephrology, Royal Free Hospital, University College London, London, UK
| | - Mato Nagel
- Centre for Nephrology and Metabolic Disorders, Weisswasser, Germany
| | - Michael Yau
- Genetics, Guy's Hospital, Viapath, London, UK
| | - Lev Shagam
- Institute of Pediatrics, Pirogov Russian Medical University, Moscow, Russia
| | - Roser Torra
- Inherited Kidney Disorders, Nephrology Department, Fundacio Puigvert, Instituto de Investigacion Carlos III, Universitat Autonoma de Barcelona, Barcelona, Spain
| | - Elisabet Ars
- Molecular Biology Laboratory, Fundacio Puigvert, Instituto de Investigacion Carlos III, Universitat Autonoma de Barcelona, Barcelona, Spain
| | - Julia Hoefele
- Institute of Human Genetics, Technical University Munich, Munich, Germany
| | - Guido Garosi
- Nephrology, Dialysis and Transplantation, Azienda Ospedaliera Universitaria Senese, Siena, Italy
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15
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Somatic Mosaicism in a Male Patient With X-linked Alport Syndrome. Kidney Int Rep 2019; 4:1031-1035. [PMID: 31312776 PMCID: PMC6609819 DOI: 10.1016/j.ekir.2019.03.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 02/25/2019] [Accepted: 03/04/2019] [Indexed: 01/16/2023] Open
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16
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Abstract
Alport syndrome (AS) is a progressive hereditary renal disease that is characterized by sensorineural hearing loss and ocular abnormalities. It is divided into three modes of inheritance, namely, X-linked Alport syndrome (XLAS), autosomal recessive AS (ARAS), and autosomal dominant AS (ADAS). XLAS is caused by pathogenic variants in COL4A5, while ADAS and ARAS are caused by those in COL4A3/COL4A4. Diagnosis is conventionally made pathologically, but recent advances in comprehensive genetic analysis have enabled genetic testing to be performed for the diagnosis of AS as first-line diagnosis. Because of these advances, substantial information about the genetics of AS has been obtained and the genetic background of this disease has been revealed, including genotype-phenotype correlations and mechanisms of onset in some male XLAS cases that lead to milder phenotypes of late-onset end-stage renal disease (ESRD). There is currently no radical therapy for AS and treatment is only performed to delay progression to ESRD using nephron-protective drugs. Angiotensin-converting enzyme inhibitors can remarkably delay the development of ESRD. Recently, some new drugs for this disease have entered clinical trials or been developed in laboratories. In this article, we review the diagnostic strategy, genotype-phenotype correlation, mechanisms of onset of milder phenotypes, and treatment of AS, among others.
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17
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Nozu K, Nakanishi K, Abe Y, Udagawa T, Okada S, Okamoto T, Kaito H, Kanemoto K, Kobayashi A, Tanaka E, Tanaka K, Hama T, Fujimaru R, Miwa S, Yamamura T, Yamamura N, Horinouchi T, Minamikawa S, Nagata M, Iijima K. A review of clinical characteristics and genetic backgrounds in Alport syndrome. Clin Exp Nephrol 2018; 23:158-168. [PMID: 30128941 PMCID: PMC6510800 DOI: 10.1007/s10157-018-1629-4] [Citation(s) in RCA: 112] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 08/06/2018] [Indexed: 01/15/2023]
Abstract
Alport syndrome (AS) is a progressive hereditary renal disease that is characterized by sensorineural hearing loss and ocular abnormalities. It is divided into three modes of inheritance, namely, X-linked Alport syndrome (XLAS), autosomal recessive AS (ARAS), and autosomal dominant AS (ADAS). XLAS is caused by pathogenic variants in COL4A5, while ADAS and ARAS are caused by those in COL4A3/COL4A4. Diagnosis is conventionally made pathologically, but recent advances in comprehensive genetic analysis have enabled genetic testing to be performed for the diagnosis of AS as first-line diagnosis. Because of these advances, substantial information about the genetics of AS has been obtained and the genetic background of this disease has been revealed, including genotype–phenotype correlations and mechanisms of onset in some male XLAS cases that lead to milder phenotypes of late-onset end-stage renal disease (ESRD). There is currently no radical therapy for AS and treatment is only performed to delay progression to ESRD using nephron-protective drugs. Angiotensin-converting enzyme inhibitors can remarkably delay the development of ESRD. Recently, some new drugs for this disease have entered clinical trials or been developed in laboratories. In this article, we review the diagnostic strategy, genotype–phenotype correlation, mechanisms of onset of milder phenotypes, and treatment of AS, among others.
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Affiliation(s)
- Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan.
| | - Koichi Nakanishi
- Department of Child Health and Welfare (Pediatrics), Graduate School of Medicine, University of the Ryukyus, Nishihara, Japan
| | - Yoshifusa Abe
- Children Medical Center, Showa University Northern Yokohama Hospital, Yokohama, Kanagawa, Japan
| | - Tomohiro Udagawa
- Department of Pediatrics and Developmental Biology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Shinichi Okada
- Division of Pediatrics and Perinatology, Faculty of Medicine, Tottori University, Tottori, Japan
| | - Takayuki Okamoto
- Department of Pediatrics, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Hiroshi Kaito
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan
| | - Katsuyoshi Kanemoto
- Department of Pediatrics, National Hospital Organization Chiba-East Hospital, Chiba, Japan
| | - Anna Kobayashi
- Department of Pediatrics, Faculty of Medicine, University of Yamanashi, Kofu, Japan
| | - Eriko Tanaka
- Department of Pediatrics and Developmental Biology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Kazuki Tanaka
- Department of Nephrology, Aichi Children's Health and Medical Center, Obu, Japan
| | - Taketsugu Hama
- Department of Pediatrics, Wakayama Medical University, Wakayama, Japan
| | - Rika Fujimaru
- Department of Pediatrics, Osaka City General Hospital, Izumi, Japan
| | - Saori Miwa
- Department of Pediatrics, The Jikei University School of Medicine, Tokyo, Japan
| | - Tomohiko Yamamura
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan
| | - Natsusmi Yamamura
- Department of Pediatric Nephrology and Metabolism, Osaka Women's and Children's Hospital, Izumi, Japan
| | - Tomoko Horinouchi
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan
| | - Shogo Minamikawa
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan
| | - Michio Nagata
- Kidney and Vascular Pathology, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Kazumoto Iijima
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan
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18
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Germline mosaicism is a pitfall in the diagnosis of “sporadic” X-linked Alport syndrome. J Nephrol 2018; 32:155-159. [DOI: 10.1007/s40620-018-0518-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 07/15/2018] [Indexed: 12/13/2022]
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19
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Genomic mosaicism in paternal sperm and multiple parental tissues in a Dravet syndrome cohort. Sci Rep 2017; 7:15677. [PMID: 29142202 PMCID: PMC5688122 DOI: 10.1038/s41598-017-15814-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Accepted: 11/02/2017] [Indexed: 12/21/2022] Open
Abstract
Genomic mosaicism in parental gametes and peripheral tissues is an important consideration for genetic counseling. We studied a Chinese cohort affected by a severe epileptic disorder, Dravet syndrome (DS). There were 56 fathers who donated semen and 15 parents who donated multiple peripheral tissue samples. We used an ultra-sensitive quantification method, micro-droplet digital PCR (mDDPCR), to detect parental mosaicism of the proband’s pathogenic mutation in SCN1A, the causal gene of DS in 112 families. Ten of the 56 paternal sperm samples were found to exhibit mosaicism of the proband’s mutations, with mutant allelic fractions (MAFs) ranging from 0.03% to 39.04%. MAFs in the mosaic fathers’ sperm were significantly higher than those in their blood (p = 0.00098), even after conditional probability correction (p’ = 0.033). In three mosaic fathers, ultra-low fractions of mosaicism (MAF < 1%) were detected in the sperm samples. In 44 of 45 cases, mosaicism was also observed in other parental peripheral tissues. Hierarchical clustering showed that MAFs measured in the paternal sperm, hair follicles and urine samples were clustered closest together. Milder epileptic phenotypes were more likely to be observed in mosaic parents (p = 3.006e-06). Our study provides new insights for genetic counseling.
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Yokota K, Nozu K, Minamikawa S, Yamamura T, Nakanishi K, Kaneda H, Hamada R, Nozu Y, Shono A, Ninchoji T, Morisada N, Ishimori S, Fujimura J, Horinouchi T, Kaito H, Nakanishi K, Morioka I, Taniguchi-Ikeda M, Iijima K. Female X-linked Alport syndrome with somatic mosaicism. Clin Exp Nephrol 2016; 21:877-883. [DOI: 10.1007/s10157-016-1352-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 10/16/2016] [Indexed: 01/15/2023]
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