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Ramanagoudr-Bhojappa R, Tryon R, Lach FP, Donovan FX, Maxwell R, Rosenberg A, MacMillan ML, Wagner JE, Auerbach AD, Smogorzewska A, Chandrasekharappa SC. FANCA c.3624C>T (p.Ser1208=) is a hypomorphic splice variant associated with delayed onset of Fanconi anemia. Blood Adv 2024; 8:899-908. [PMID: 38191666 PMCID: PMC10875269 DOI: 10.1182/bloodadvances.2023011888] [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] [Received: 10/09/2023] [Revised: 12/28/2023] [Accepted: 12/31/2023] [Indexed: 01/10/2024] Open
Abstract
ABSTRACT Fanconi anemia (FA) is a hereditary, DNA repair deficiency disorder caused by pathogenic variants in any 1 of 22 known genes (FANCA-FANCW). Variants in FANCA account for nearly two-thirds of all patients with FA. Clinical presentation of FA can be heterogeneous and include congenital abnormalities, progressive bone marrow failure, and predisposition to cancer. Here, we describe a relatively mild disease manifestation among 6 individuals diagnosed with FA, each compound heterozygous for 1 established pathogenic FANCA variant and 1 FANCA exon 36 variant, c.3624C>T. These individuals had delayed onset of hematological abnormalities, increased survival, reduced incidence of cancer, and improved fertility. Although predicted to encode a synonymous change (p.Ser1208=), the c.3624C>T variant causes a splicing error resulting in a FANCA transcript missing the last 4 base pairs of exon 36. Deep sequencing and quantitative reverse transcription polymerase chain reaction analysis revealed that 6% to 10% of the FANCA transcripts included the canonical splice product, which generated wild-type FANCA protein. Consistently, functional analysis of cell lines from the studied individuals revealed presence of residual FANCD2 ubiquitination and FANCD2 foci formation, better cell survival, and decreased late S/G2 accumulation in response to DNA interstrand cross-linking agent, indicating presence of residual activity of the FA repair pathway. Thus, the c.3624C>T variant is a hypomorphic allele, which contributes to delayed manifestation of FA disease phenotypes in individuals with at least 1 c.3624C>T allele.
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Affiliation(s)
- Ramanagouda Ramanagoudr-Bhojappa
- Cancer Genomics Unit, Cancer Genetics and Comparative Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD
| | - Rebecca Tryon
- Department of Genetics, University of Minnesota, Minneapolis, MN
| | - Francis P. Lach
- Laboratory of Genome Maintenance, The Rockefeller University, New York, NY
| | - Frank X. Donovan
- Cancer Genomics Unit, Cancer Genetics and Comparative Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD
| | - Rochelle Maxwell
- Laboratory of Genome Maintenance, The Rockefeller University, New York, NY
| | - Allana Rosenberg
- Laboratory of Genome Maintenance, The Rockefeller University, New York, NY
| | - Margaret L. MacMillan
- Division of Pediatric Blood and Marrow Transplantation, Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN
| | - John E. Wagner
- Division of Pediatric Blood and Marrow Transplantation, Department of Pediatrics, University of Minnesota Medical School, Minneapolis, MN
| | - Arleen D. Auerbach
- Human Genetics and Hematology Program, The Rockefeller University, New York, NY
| | - Agata Smogorzewska
- Laboratory of Genome Maintenance, The Rockefeller University, New York, NY
| | - Settara C. Chandrasekharappa
- Cancer Genomics Unit, Cancer Genetics and Comparative Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD
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2
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Joshi G, Arthur NBJ, Geetha TS, Datari PVR, Modak K, Roy D, Chaudhury AD, Sundaraganesan P, Priyanka S, Na F, Ramprasad V, Abraham A, Srivastava VM, Srivastava A, Kulkarni UP, George B, Velayudhan SR. Comprehensive laboratory diagnosis of Fanconi anaemia: comparison of cellular and molecular analysis. J Med Genet 2023; 60:801-809. [PMID: 36894310 PMCID: PMC10423531 DOI: 10.1136/jmg-2022-108714] [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: 05/18/2022] [Accepted: 12/03/2022] [Indexed: 03/11/2023]
Abstract
BACKGROUND Fanconi anaemia (FA) is a rare inherited bone marrow failure disease caused by germline pathogenic variants in any of the 22 genes involved in the FA-DNA interstrand crosslink (ICL) repair pathway. Accurate laboratory investigations are required for FA diagnosis for the clinical management of the patients. We performed chromosome breakage analysis (CBA), FANCD2 ubiquitination (FANCD2-Ub) analysis and exome sequencing of 142 Indian patients with FA and evaluated the efficiencies of these methods in FA diagnosis. METHODS We performed CBA and FANCD2-Ub analysis in the blood cells and fibroblasts of patients with FA. Exome sequencing with improved bioinformatics to detect the single number variants and CNV was carried out for all the patients. Functional validation of the variants with unknown significance was done by lentiviral complementation assay. RESULTS Our study showed that FANCD2-Ub analysis and CBA on peripheral blood cells could diagnose 97% and 91.5% of FA cases, respectively. Exome sequencing identified the FA genotypes consisting of 45 novel variants in 95.7% of the patients with FA. FANCA (60.2%), FANCL (19.8%) and FANCG (11.7%) were the most frequently mutated genes in the Indian population. A FANCL founder mutation c.1092G>A; p.K364=was identified at a very high frequency (~19%) in our patients. CONCLUSION We performed a comprehensive analysis of the cellular and molecular tests for the accurate diagnosis of FA. A new algorithm for rapid and cost-effective molecular diagnosis for~90% of FA cases has been established.
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Affiliation(s)
- Gaurav Joshi
- Department of Haematology, Christian Medical College Vellore, Vellore, Tamil Nadu, India
- Sree Chitra Tirunal Institute for Medical Sciences and Technology, Thiruvananthapuram, Kerala, India
| | | | | | | | - Kirti Modak
- Department of Haematology, Christian Medical College Vellore, Vellore, Tamil Nadu, India
| | - Debanjan Roy
- Department of Haematology, Christian Medical College Vellore, Vellore, Tamil Nadu, India
- Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Anurag Dutta Chaudhury
- Department of Haematology, Christian Medical College Vellore, Vellore, Tamil Nadu, India
| | | | - Sweety Priyanka
- Department of Haematology, Christian Medical College Vellore, Vellore, Tamil Nadu, India
| | - Fouzia Na
- Department of Haematology, Christian Medical College Vellore, Vellore, Tamil Nadu, India
| | | | - Aby Abraham
- Department of Haematology, Christian Medical College Vellore, Vellore, Tamil Nadu, India
| | - Vivi M Srivastava
- Department of Cytogenetics, Christian Medical College Vellore, Vellore, Tamil Nadu, India
| | - Alok Srivastava
- Department of Haematology, Christian Medical College Vellore, Vellore, Tamil Nadu, India
- Center for Stem Cell Research, Vellore, Tamil Nadu, India
| | - Uday Prakash Kulkarni
- Department of Haematology, Christian Medical College Vellore, Vellore, Tamil Nadu, India
| | - Biju George
- Department of Haematology, Christian Medical College Vellore, Vellore, Tamil Nadu, India
| | - Shaji R Velayudhan
- Department of Haematology, Christian Medical College Vellore, Vellore, Tamil Nadu, India
- Center for Stem Cell Research, Vellore, Tamil Nadu, India
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3
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Doubaj Y, Zrhidri A, Elalaoui SC, Lyahyai J, El Kadiri Y, Elkassimi N, Sbiti A, El Kababri M, Hessissen L, Sefiani A. Clinical, cytogenetic and molecular findings in nine Moroccan patients with Fanconi anemia. Pan Afr Med J 2021; 39:72. [PMID: 34422195 PMCID: PMC8363957 DOI: 10.11604/pamj.2021.39.72.27220] [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: 11/29/2020] [Accepted: 05/12/2021] [Indexed: 11/30/2022] Open
Abstract
Introduction Fanconi anemia (FA) is a rare inherited hematological disease due to a defect in the DNA repair pathway resulting in congenital abnormalities and high susceptibility to develop cancers. The cytogenetic analysis using alkylating agents is still a reference test to establish the diagnosis. Despite the genetic heterogeneity, the identification of the causal mutation is actually performed especially after the development of next generation sequencing (NGS). Methods we report here nine Moroccan patients referred to the department of Medical Genetics for suspicion of FA. We realized a genetic consultation to establish a clinical record with biological data before carrying out the genetic analysis. Karyotyping with mitomycin was performed for all the probands before elaborating molecular study. We used massively parallel sequencing to analyse the three most frequent mutated genes FANCA, FANCC, and FANCG, representing 84% of all genes involved in FA. Results all the patients showed hematological signs associated with at least one extra-hematological congenital anomaly. The chromosomal breaks were significantly higher for the nine patients, compared to the controls. The molecular diagnosis was confirmed in 8 of the 9 families tested (88.8%) with 4 novel mutations. The next generation based sequencing identified 9 variations: 6 in the FANCA gene (66.6%), 3 in the FANCG gene (33.3%) and no FANCC variation was found. Of those, 7 were homozygous and 2 were compounds heterozygous. Conclusion to the best of our knowledge, this is the first molecular report of Moroccan patients with FA suggesting the predominance of two genes without any recurrent mutation. The molecular analysis of FANCA and FANCG genes should be offered first for all patients in Morocco.
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Affiliation(s)
- Yassamine Doubaj
- Centre de Recherche en Génomique et Pathologies Humaines (Centre GENOPATH), Faculté de Médecine et de Pharmacie, Université Mohammed V, Rabat, Maroc.,Département de Génétique Médicale, Institut National d'Hygiène, Rabat, Maroc
| | - Abdelali Zrhidri
- Centre de Recherche en Génomique et Pathologies Humaines (Centre GENOPATH), Faculté de Médecine et de Pharmacie, Université Mohammed V, Rabat, Maroc
| | - Siham Chafai Elalaoui
- Centre de Recherche en Génomique et Pathologies Humaines (Centre GENOPATH), Faculté de Médecine et de Pharmacie, Université Mohammed V, Rabat, Maroc.,Département de Génétique Médicale, Institut National d'Hygiène, Rabat, Maroc
| | - Jaber Lyahyai
- Centre de Recherche en Génomique et Pathologies Humaines (Centre GENOPATH), Faculté de Médecine et de Pharmacie, Université Mohammed V, Rabat, Maroc
| | - Youssef El Kadiri
- Centre de Recherche en Génomique et Pathologies Humaines (Centre GENOPATH), Faculté de Médecine et de Pharmacie, Université Mohammed V, Rabat, Maroc
| | - Nadia Elkassimi
- Département de Génétique Médicale, Institut National d'Hygiène, Rabat, Maroc
| | - Aziza Sbiti
- Département de Génétique Médicale, Institut National d'Hygiène, Rabat, Maroc
| | - Maria El Kababri
- Centre d´Hématologie et Oncologie Pédiatrique, Hôpital d´Enfants, Rabat, Maroc
| | - Laila Hessissen
- Centre d´Hématologie et Oncologie Pédiatrique, Hôpital d´Enfants, Rabat, Maroc
| | - Abdelaziz Sefiani
- Centre de Recherche en Génomique et Pathologies Humaines (Centre GENOPATH), Faculté de Médecine et de Pharmacie, Université Mohammed V, Rabat, Maroc.,Département de Génétique Médicale, Institut National d'Hygiène, Rabat, Maroc
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4
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Ben Haj Ali A, Messaoud O, Elouej S, Talmoudi F, Ayed W, Mellouli F, Ouederni M, Hadiji S, De Sandre-Giovannoli A, Delague V, Lévy N, Bogliolo M, Surrallés J, Abdelhak S, Amouri A. FANCA Gene Mutations in North African Fanconi Anemia Patients. Front Genet 2021; 12:610050. [PMID: 33679882 PMCID: PMC7933650 DOI: 10.3389/fgene.2021.610050] [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: 09/24/2020] [Accepted: 01/22/2021] [Indexed: 11/27/2022] Open
Abstract
Populations in North Africa (NA) are characterized by a high rate of consanguinity. Consequently, the proportion of founder mutations might be higher than expected and could be a major cause for the high prevalence of recessive genetic disorders like Fanconi anemia (FA). We report clinical, cytogenetic, and molecular characterization of FANCA in 29 North African FA patients from Tunisia, Libya, and Algeria. Cytogenetic tests revealed high rates of spontaneous chromosome breakages for all patients except two of them. FANCA molecular analysis was performed using three different molecular approaches which allowed us to identify causal mutations as homozygous or compound heterozygous forms. It included a nonsense mutation (c.2749C > T; p.Arg917Ter), one reported missense mutation (c.1304G > A; p.Arg435His), a novel missense variant (c.1258G > A; p.Asp409Glu), and the FANCA most common reported mutation (c.3788_3790delTCT; p.Phe1263del). Furthermore, three founder mutations were identified in 86.7% of the 22 Tunisian patients: (1) a deletion of exon 15, in 36.4% patients (8/22); (2), a deletion of exons 4 and 5 in 23% (5/22) and (3) an intronic mutation c.2222 + 166G > A, in 27.3% (6/22). Despite the relatively small number of patients studied, our results depict the mutational landscape of FA among NA populations and it should be taken into consideration for appropriate genetic counseling.
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Affiliation(s)
- Abir Ben Haj Ali
- Department of Histology and Cytogenetics, Institut Pasteur de Tunis, Université Tunis El Manar, Tunis, Tunisia.,Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur de Tunis, Université Tunis El Manar, Tunis, Tunisia
| | - Olfa Messaoud
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur de Tunis, Université Tunis El Manar, Tunis, Tunisia
| | - Sahar Elouej
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur de Tunis, Université Tunis El Manar, Tunis, Tunisia.,INSERM, MMG, UMR 1251, Aix Marseille University, Marseille, France
| | - Faten Talmoudi
- Department of Histology and Cytogenetics, Institut Pasteur de Tunis, Université Tunis El Manar, Tunis, Tunisia.,Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur de Tunis, Université Tunis El Manar, Tunis, Tunisia
| | - Wiem Ayed
- Department of Histology and Cytogenetics, Institut Pasteur de Tunis, Université Tunis El Manar, Tunis, Tunisia.,Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur de Tunis, Université Tunis El Manar, Tunis, Tunisia
| | - Fethi Mellouli
- Department of Peadiatric Immuno-Haematology, National Bone Marrow Transplantation, Tunis, Tunisia
| | - Monia Ouederni
- Department of Peadiatric Immuno-Haematology, National Bone Marrow Transplantation, Tunis, Tunisia
| | - Sondes Hadiji
- Haematology Department, Hedi Chaker Hospital, University of Sfax, Sfax, Tunisia
| | | | - Valérie Delague
- INSERM, MMG, UMR 1251, Aix Marseille University, Marseille, France
| | - Nicolas Lévy
- INSERM, MMG, UMR 1251, Aix Marseille University, Marseille, France
| | - Massimo Bogliolo
- Research Institute IIB Sant Pau, Hospital de la Santa Creu i Sant Pau, Universitat Autonoma de Barcelona, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Jordi Surrallés
- Research Institute IIB Sant Pau, Hospital de la Santa Creu i Sant Pau, Universitat Autonoma de Barcelona, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Sonia Abdelhak
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur de Tunis, Université Tunis El Manar, Tunis, Tunisia
| | - Ahlem Amouri
- Department of Histology and Cytogenetics, Institut Pasteur de Tunis, Université Tunis El Manar, Tunis, Tunisia.,Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur de Tunis, Université Tunis El Manar, Tunis, Tunisia
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5
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Ben Haj Ali A, Amouri A, Sayeb M, Makni S, Hammami W, Naouali C, Dallali H, Romdhane L, Bashamboo A, McElreavey K, Abdelhak S, Messaoud O. Cytogenetic and molecular diagnosis of Fanconi anemia revealed two hidden phenotypes: Disorder of sex development and cerebro-oculo-facio-skeletal syndrome. Mol Genet Genomic Med 2019; 7:e00694. [PMID: 31124294 PMCID: PMC6625148 DOI: 10.1002/mgg3.694] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 02/14/2019] [Accepted: 04/01/2019] [Indexed: 12/11/2022] Open
Abstract
Background Several studies have shown a high rate of consanguinity and endogamy in North African populations. As a result, the frequency of autosomal recessive diseases is relatively high in the region with the co‐occurrence of two or more diseases. Methods We report here on a consanguineous Libyan family whose child was initially diagnosed as presenting Fanconi anemia (FA) with uncommon skeletal deformities. The chromosome breakage test has been performed using mitomycin C (MMC) while molecular analysis was performed by a combined approach of linkage analysis and whole exome sequencing. Results Cytogenetic analyses showed that the karyotype of the female patient is 46,XY suggesting the diagnosis of a disorder of sex development (DSD). By looking at the genetic etiology of FA and DSD, we have identified p.[Arg798*];[Arg798*] mutation in FANCJ (OMIM #605882) gene responsible for FA and p.[Arg108*];[Arg1497Trp] in EFCAB6 (Gene #64800) gene responsible for DSD. In addition, we have incidentally discovered a novel mutation p.[Gly1372Arg];[Gly1372Arg] in the ERCC6 (CSB) (OMIM #609413) gene responsible for COFS that might explain the atypical severe skeletal deformities. Conclusion The co‐occurrence of clinical and overlapping genetic heterogeneous entities should be taken into consideration for better molecular and genetic counseling.
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Affiliation(s)
- Abir Ben Haj Ali
- Laboratory of Histology and Cytogenetics, Institut Pasteur de Tunis, University Tunis El Manar, Tunis, Tunisia.,Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur de Tunis, University Tunis El Manar, Tunis, Tunisia
| | - Ahlem Amouri
- Laboratory of Histology and Cytogenetics, Institut Pasteur de Tunis, University Tunis El Manar, Tunis, Tunisia.,Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur de Tunis, University Tunis El Manar, Tunis, Tunisia
| | - Marwa Sayeb
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur de Tunis, University Tunis El Manar, Tunis, Tunisia
| | | | - Wajih Hammami
- Laboratory of Histology and Cytogenetics, Institut Pasteur de Tunis, University Tunis El Manar, Tunis, Tunisia.,Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur de Tunis, University Tunis El Manar, Tunis, Tunisia
| | - Chokri Naouali
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur de Tunis, University Tunis El Manar, Tunis, Tunisia
| | - Hamza Dallali
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur de Tunis, University Tunis El Manar, Tunis, Tunisia
| | - Lilia Romdhane
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur de Tunis, University Tunis El Manar, Tunis, Tunisia
| | - Anu Bashamboo
- Human Developmental Genetics, Institut Pasteur de Paris, Paris, France
| | | | - Sonia Abdelhak
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur de Tunis, University Tunis El Manar, Tunis, Tunisia
| | - Olfa Messaoud
- Laboratory of Biomedical Genomics and Oncogenetics, Institut Pasteur de Tunis, University Tunis El Manar, Tunis, Tunisia
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6
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Kimble DC, Lach FP, Gregg SQ, Donovan FX, Flynn EK, Kamat A, Young A, Vemulapalli M, Thomas JW, Mullikin JC, Auerbach AD, Smogorzewska A, Chandrasekharappa SC. A comprehensive approach to identification of pathogenic FANCA variants in Fanconi anemia patients and their families. Hum Mutat 2018; 39:237-254. [PMID: 29098742 PMCID: PMC5762269 DOI: 10.1002/humu.23366] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 10/20/2017] [Accepted: 10/22/2017] [Indexed: 11/11/2022]
Abstract
Fanconi anemia (FA) is a rare recessive DNA repair deficiency resulting from mutations in one of at least 22 genes. Two-thirds of FA families harbor mutations in FANCA. To genotype patients in the International Fanconi Anemia Registry (IFAR) we employed multiple methodologies, screening 216 families for FANCA mutations. We describe identification of 57 large deletions and 261 sequence variants, in 159 families. All but seven families harbored distinct combinations of two mutations demonstrating high heterogeneity. Pathogenicity of the 18 novel missense variants was analyzed functionally by determining the ability of the mutant cDNA to improve the survival of a FANCA-null cell line when treated with MMC. Overexpressed pathogenic missense variants were found to reside in the cytoplasm, and nonpathogenic in the nucleus. RNA analysis demonstrated that two variants (c.522G > C and c.1565A > G), predicted to encode missense variants, which were determined to be nonpathogenic by a functional assay, caused skipping of exons 5 and 16, respectively, and are most likely pathogenic. We report 48 novel FANCA sequence variants. Defining both variants in a large patient cohort is a major step toward cataloging all FANCA variants, and permitting studies of genotype-phenotype correlations.
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Affiliation(s)
- Danielle C Kimble
- Cancer Genetics and Comparative Genomics Branch, National Human Genome Research Institute, Bethesda, Maryland
| | - Francis P Lach
- Laboratory of Genome Maintenance, The Rockefeller University, New York, New York
| | - Siobhan Q Gregg
- Laboratory of Genome Maintenance, The Rockefeller University, New York, New York
| | - Frank X Donovan
- Cancer Genetics and Comparative Genomics Branch, National Human Genome Research Institute, Bethesda, Maryland
| | - Elizabeth K Flynn
- Cancer Genetics and Comparative Genomics Branch, National Human Genome Research Institute, Bethesda, Maryland
| | - Aparna Kamat
- Cancer Genetics and Comparative Genomics Branch, National Human Genome Research Institute, Bethesda, Maryland
| | - Alice Young
- NIH Intramural Sequencing Center, National Human Genome Research Institute, Bethesda, Maryland
| | - Meghana Vemulapalli
- NIH Intramural Sequencing Center, National Human Genome Research Institute, Bethesda, Maryland
| | - James W Thomas
- NIH Intramural Sequencing Center, National Human Genome Research Institute, Bethesda, Maryland
| | - James C Mullikin
- NIH Intramural Sequencing Center, National Human Genome Research Institute, Bethesda, Maryland
| | - Arleen D Auerbach
- Human Genetics and Hematology Program, The Rockefeller University, New York, New York
| | - Agata Smogorzewska
- Laboratory of Genome Maintenance, The Rockefeller University, New York, New York
| | - Settara C Chandrasekharappa
- Cancer Genetics and Comparative Genomics Branch, National Human Genome Research Institute, Bethesda, Maryland
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7
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Flynn EK, Kamat A, Lach FP, Donovan FX, Kimble DC, Narisu N, Sanborn E, Boulad F, Davies SM, Gillio AP, Harris RE, MacMillan ML, Wagner JE, Smogorzewska A, Auerbach AD, Ostrander EA, Chandrasekharappa SC. Comprehensive analysis of pathogenic deletion variants in Fanconi anemia genes. Hum Mutat 2015; 35:1342-53. [PMID: 25168418 DOI: 10.1002/humu.22680] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 08/09/2014] [Indexed: 11/06/2022]
Abstract
Fanconi anemia (FA) is a rare recessive disease resulting from mutations in one of at least 16 different genes. Mutation types and phenotypic manifestations of FA are highly heterogeneous and influence the clinical management of the disease. We analyzed 202 FA families for large deletions, using high-resolution comparative genome hybridization arrays, single-nucleotide polymorphism arrays, and DNA sequencing. We found pathogenic deletions in 88 FANCA, seven FANCC, two FANCD2, and one FANCB families. We find 35% of FA families carry large deletions, accounting for 18% of all FA pathogenic variants. Cloning and sequencing across the deletion breakpoints revealed that 52 FANCA deletion ends, and one FANCC deletion end extended beyond the gene boundaries, potentially affecting neighboring genes with phenotypic consequences. Seventy-five percent of the FANCA deletions are Alu-Alu mediated, predominantly by AluY elements, and appear to be caused by nonallelic homologous recombination. Individual Alu hotspots were identified. Defining the haplotypes of four FANCA deletions shared by multiple families revealed that three share a common ancestry. Knowing the exact molecular changes that lead to the disease may be critical for a better understanding of the FA phenotype, and to gain insight into the mechanisms driving these pathogenic deletion variants.
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Affiliation(s)
- Elizabeth K Flynn
- Cancer Genetics Branch, National Human Genome Research Institute, NIH, Bethesda, Maryland, 20892
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8
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Park J, Kim M, Jang W, Chae H, Kim Y, Chung NG, Lee JW, Cho B, Jeong DC, Park IY, Park MS. Founder haplotype analysis of Fanconi anemia in the Korean population finds common ancestral haplotypes for a FANCG variant. Ann Hum Genet 2015; 79:153-61. [PMID: 25703136 DOI: 10.1111/ahg.12097] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Accepted: 11/19/2014] [Indexed: 11/28/2022]
Abstract
A common ancestral haplotype is strongly suggested in the Korean and Japanese patients with Fanconi anemia (FA), because common mutations have been frequently found: c.2546delC and c.3720_3724delAAACA of FANCA; c.307+1G>C, c.1066C>T, and c.1589_1591delATA of FANCG. Our aim in this study was to investigate the origin of these common mutations of FANCA and FANCG. We genotyped 13 FA patients consisting of five FA-A patients and eight FA-G patients from the Korean FA population. Microsatellite markers used for haplotype analysis included four CA repeat markers which are closely linked with FANCA and eight CA repeat markers which are contiguous with FANCG. As a result, Korean FA-A patients carrying c.2546delC or c.3720_3724delAAACA did not share the same haplotypes. However, three unique haplotypes carrying c.307+1G>C, c.1066C > T, or c.1589_1591delATA, that consisted of eight polymorphic loci covering a flanking region were strongly associated with Korean FA-G, consistent with founder haplotypes reported previously in the Japanese FA-G population. Our finding confirmed the common ancestral haplotypes on the origins of the East Asian FA-G patients, which will improve our understanding of the molecular population genetics of FA-G. To the best of our knowledge, this is the first report on the association between disease-linked mutations and common ancestral haplotypes in the Korean FA population.
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Affiliation(s)
- Joonhong Park
- Department of Laboratory Medicine, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea; Catholic Genetic Laboratory Center, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
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