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Unravelling the genetic and phenotypic heterogeneity of SPTA1 gene variants in Hereditary Elliptocytosis and Hereditary Pyropoikilocytosis patients using next-generation sequencing. Gene 2022; 843:146796. [PMID: 35961434 DOI: 10.1016/j.gene.2022.146796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 07/25/2022] [Accepted: 08/05/2022] [Indexed: 11/22/2022]
Abstract
Hereditary Elliptocytosis (HE) and Hereditary Pyropoikilocytosis (HPP) are clinically and genetically heterogeneous red cell membranopathies that result from the defects in the horizontal linkage between RBC (red blood cell) membrane and cytoskeletal proteins affecting its mechanical stability and deformability thereby reducing its lifespan. The principal defect in HE and HPP is due to dysfunction or deficiency of RBC cytoskeletal proteins namely, α-spectrin (SPTA1), β-spectrin (SPTB) and protein 4.1R (EPB41R). This study reports the genetic and phenotypic heterogeneity of 10 Indian patients (5 with HE and 5 with HPP)harboringSPTA1 gene variants. We used targeted next-generation sequencing (t-NGS) to characterize the causative genetic variants in 10 HE/HPP suspected patients and studied the correlation between the identified variants with their corresponding phenotypic features.t-NGS detected 12 SPTA1 variants, out of which 8 are novel. Nearly all of the detected variants have a damaging effect on the protein stability and function, as shown by the insilico analysis. The possible effect of the detected variants on the protein structure was studied using the HOPE software and DynaMut tools wherever possible. To the best of our knowledge, this is the first report on HE/HPP cases confirmed by a genetic study from India. To conclude, HE is caused by monoallelic mutations while HPP, the more severe form, is typically caused by biallelic (homozygous or compound heterozygous) mutations justifying the phenotypic heterogeneity associated with patients. Moreover, analysis at the molecular level by NGS permits diagnosis in these disorders with highly variable heterogeneity requiring regular transfusions and may facilitate prognostic contemplations.
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2
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Muñoz G, García-Seisdedos D, Ciubotariu C, Piris-Villaespesa M, Gandía M, Martín-Moro F, Gutiérrez-Solana LG, Morado M, López-Jiménez J, Sánchez-Herranz A, Villarrubia J, Del Castillo FJ. Early detection of lysosomal diseases by screening of cases of idiopathic splenomegaly and/or thrombocytopenia with a next-generation sequencing gene panel. JIMD Rep 2019; 51:53-61. [PMID: 32071839 PMCID: PMC7012743 DOI: 10.1002/jmd2.12078] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 09/06/2019] [Accepted: 09/12/2019] [Indexed: 02/02/2023] Open
Abstract
Lysosomal diseases (LD) are a group of about 70 rare hereditary disorders (combined incidence 1:5000) in which diverse lysosomal functions are impaired, impacting multiple organs and systems. The first clinical signs and symptoms are usually unspecific and shared by hundreds of other disorders. Diagnosis of LD traditionally relies on performing specific enzymatic assays, if available, upon clinical suspicion of the disorder. However, the combination of the insidious onset of LD and the lack of awareness on these rare diseases among medical personnel results in undesirable diagnostic delays, with unchecked disease progression, appearance of complications and a worsened prognosis. We tested the usefulness of a next‐generation sequencing‐based gene panel for quick, early detection of LD among cases of idiopathic splenomegaly and/or thrombocytopenia, two of the earliest clinical signs observed in most LD. Our 73‐gene panel interrogated 28 genes for LD, 1 biomarker and 44 genes underlying non‐LD differential diagnoses. Among 38 unrelated patients, we elucidated eight cases (21%), five with LD (GM1 gangliosidosis, Sanfilippo disease A and B, Niemann‐Pick disease B, Gaucher disease) and three with non‐LD conditions. Interestingly, we identified three LD patients harboring pathogenic mutations in two LD genes each, which may result in unusual disease presentations and impact treatment. Turnaround time for panel screening and genetic validation was 1 month. Our results underline the usefulness of resequencing gene panels for quick and cost‐effective screening of LDs and disorders sharing with them early clinical signs.
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Affiliation(s)
- Gloria Muñoz
- UCA de Genómica Traslacional Hospital Universitario Ramón y Cajal, IRYCIS Madrid Spain
| | | | - Crina Ciubotariu
- UCA de Genómica Traslacional Hospital Universitario Ramón y Cajal, IRYCIS Madrid Spain
| | | | - Marta Gandía
- UCA de Genómica Traslacional Hospital Universitario Ramón y Cajal, IRYCIS Madrid Spain
| | - Fernando Martín-Moro
- Servicio de Hematología Hospital Universitario Ramón y Cajal, IRYCIS Madrid Spain
| | - Luis G Gutiérrez-Solana
- Consulta de Neurodegenerativas, Servicio de Neurología Pediátrica Hospital Infantil Universitario Niño Jesús Madrid Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER) Madrid Spain
| | - Marta Morado
- Servicio de Hematología Hospital Universitario La Paz Madrid Spain
| | - Javier López-Jiménez
- Servicio de Hematología Hospital Universitario Ramón y Cajal, IRYCIS Madrid Spain
| | | | - Jesús Villarrubia
- UCA de Genómica Traslacional Hospital Universitario Ramón y Cajal, IRYCIS Madrid Spain.,Servicio de Hematología Hospital Universitario Ramón y Cajal, IRYCIS Madrid Spain
| | - Francisco J Del Castillo
- UCA de Genómica Traslacional Hospital Universitario Ramón y Cajal, IRYCIS Madrid Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER) Madrid Spain.,Servicio de Genética Hospital Universitario Ramón y Cajal, IRYCIS Madrid Spain
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3
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Aggarwal A, Jamwal M, Sharma P, Sachdeva MUS, Bansal D, Malhotra P, Das R. Deciphering molecular heterogeneity of Indian families with hereditary spherocytosis using targeted next-generation sequencing: First South Asian study. Br J Haematol 2019; 188:784-795. [PMID: 31602632 DOI: 10.1111/bjh.16244] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 07/25/2019] [Accepted: 08/14/2019] [Indexed: 12/17/2022]
Abstract
Defects in various erythrocyte membrane proteins genes (ankyrin, band-3, β- and α-spectrin and protein 4·2) can cause hereditary spherocytosis (HS). This molecular heterogeneity of HS, together with co-inherited genetic modifiers, results in marked phenotypic variability among patients. We studied the molecular spectrum and genotype-phenotype correlations in 73 families (with 113 patients) with HS. Deleterious variants including nonsense (42%), deletions (18%), splice site (20%), missense (10%) and duplication/insertion (10%) were found in 47 patients. The variants detected included sporadic and dominantly-inherited defects in ANK1 (53·2%), SPTB (36·2%) and SLC4A1 (4·2%). Compound heterozygous variants in SPTA1 (6·4%) showed autosomal recessive inheritance. Alpha-spectrin variants were associated with severe anaemia and splenectomy alleviated symptoms. Co-inherited glucose-6-phosphate dehydrogenase (G6PD) deficiency was found in 15%. G6PD variants (n = 5) led to greater transfusion requirements (1-8 times) in males with HS. Homozygosity (41%) for the promoter variant of UGT1A1 (Gilbert syndrome) led to a significantly higher mean bilirubin level (126·54 µmol/l) with a higher frequency of cholelithiasis (30%) (P < 0·001). This first-ever south Asian study on the molecular spectrum of HS found ANK1 and SPTB genes variants to be the commonest with inheritance being sporadic/dominant. Next-generation sequencing provided a relatively sensitive and rapid tool for molecular diagnosis with a diagnostic yield of 64·4%.
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Affiliation(s)
- Anu Aggarwal
- Department of Haematology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Manu Jamwal
- Department of Haematology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Prashant Sharma
- Department of Haematology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Man Updesh Singh Sachdeva
- Department of Haematology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Deepak Bansal
- Haematology-Oncology Unit, Department of Paediatrics, Advanced Paediatrics Centre, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Pankaj Malhotra
- Department of Internal Medicine, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Reena Das
- Department of Haematology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
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4
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Bose D, Chakrabarti A. Localizing the chaperone activity of erythroid spectrin. Cytoskeleton (Hoboken) 2019; 76:383-397. [DOI: 10.1002/cm.21556] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 07/31/2019] [Accepted: 08/06/2019] [Indexed: 02/05/2023]
Affiliation(s)
- Dipayan Bose
- Crystallography and Molecular Biology DivisionSaha Institute of Nuclear Physics Kolkata India
- Homi Bhabha National Institute Mumbai India
| | - Abhijit Chakrabarti
- Crystallography and Molecular Biology DivisionSaha Institute of Nuclear Physics Kolkata India
- Homi Bhabha National Institute Mumbai India
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5
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Gallagher PG, Maksimova Y, Lezon-Geyda K, Newburger PE, Medeiros D, Hanson RD, Rothman J, Israels S, Wall DA, Sidonio RF, Sieff C, Gowans LK, Mittal N, Rivera-Santiago R, Speicher DW, Baserga SJ, Schulz VP. Aberrant splicing contributes to severe α-spectrin-linked congenital hemolytic anemia. J Clin Invest 2019; 129:2878-2887. [PMID: 31038472 DOI: 10.1172/jci127195] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The etiology of severe hemolytic anemia in most patients with recessive hereditary spherocytosis (rHS) and the related disorder hereditary pyropoikilocytosis (HPP) is unknown. Whole exome sequencing of DNA from probands of 24 rHS or HPP kindreds identified numerous mutations in erythrocyte membrane α-spectrin (SPTA1). Twenty-eight mutations were novel, with null alleles frequently found in trans to missense mutations. No mutations were identified in a third of SPTA1 alleles (17/48). Whole genome sequencing revealed linkage disequilibrium between the common rHS-linked α-spectrinBug Hill polymorphism and a rare intron 30 variant in all 17 mutation-negative alleles. In vitro minigene studies and in vivo splicing analyses revealed the intron 30 variant changes a weak alternate branch point (BP) to a strong BP. This change leads to increased utilization of an alternate 3' splice acceptor site, perturbing normal α-spectrin mRNA splicing and creating an elongated mRNA transcript. In vivo mRNA stability studies revealed the newly created termination codon in the elongated transcript activates nonsense mediated decay leading to spectrin deficiency. These results demonstrate a unique mechanism of human genetic disease contributes to the etiology of a third of cases of rHS, facilitating diagnosis and treatment of severe anemia, and identifying a new target for therapeutic manipulation.
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Affiliation(s)
- Patrick G Gallagher
- Department of Pediatrics.,Department of Genetics, and.,Department of Pathology, Yale University School of Medicine, New Haven, Connecticut, USA
| | | | | | - Peter E Newburger
- Department of Pediatrics, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Desiree Medeiros
- Kapiolani Medical Center for Women & Children, Honolulu, Hawaii, USA
| | | | - Jennifer Rothman
- Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, USA
| | - Sara Israels
- Department of Pediatrics and Child Health, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Donna A Wall
- Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Robert F Sidonio
- Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Colin Sieff
- Harvard Medical School, Dana-Farber and Boston Children's, Cancer and Blood Disorders Center, Boston, Massachusetts, USA
| | - L Kate Gowans
- Beaumont Children's Hospital, Royal Oak, Michigan, USA
| | - Nupur Mittal
- Department of Pediatrics, Rush University Medical Center, Chicago, Illinois, USA
| | - Roland Rivera-Santiago
- The Center for Systems and Computational Biology and Molecular and Cellular Oncogenesis Program, The Wistar Institute, Philadelphia, Pennsylvania, USA
| | - David W Speicher
- The Center for Systems and Computational Biology and Molecular and Cellular Oncogenesis Program, The Wistar Institute, Philadelphia, Pennsylvania, USA
| | - Susan J Baserga
- Department of Genetics, and.,Departments of Molecular Biophysics and Biochemistry and Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut, USA
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Panksepp J, Northoff G. The trans-species core SELF: The emergence of active cultural and neuro-ecological agents through self-related processing within subcortical-cortical midline networks. Conscious Cogn 2009; 18:193-215. [DOI: 10.1016/j.concog.2008.03.002] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2007] [Revised: 02/02/2008] [Accepted: 03/03/2008] [Indexed: 12/18/2022]
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Li Q, Fung LWM. Structural and dynamic study of the tetramerization region of non-erythroid alpha-spectrin: a frayed helix revealed by site-directed spin labeling electron paramagnetic resonance. Biochemistry 2009; 48:206-15. [PMID: 19072330 DOI: 10.1021/bi8013032] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The N-terminal region of alpha-spectrin is responsible for its association with beta-spectrin in a heterodimer, forming functional tetramers. Non-erythroid alpha-spectrin (alphaII-spectrin) has a significantly higher association affinity for beta-spectrin than the homologous erythroid alpha-spectrin (alphaI-spectrin). We have previously determined the solution structure of the N-terminal region of alphaI-spectrin by NMR methods, but currently no structural information is available for alphaII-spectrin. We have used cysteine scanning, spin labeling electron paramagnetic resonance (EPR), and isothermal titration calorimetry (ITC) methods to study the tetramerization region of alphaII-spectrin. EPR data clearly show that, in alphaII-spectrin, the first nine N-terminal residues were unstructured, followed by an irregular helix (helix C'), frayed at the N-terminal end, but rigid at the C-terminal end, which merges into the putative triple-helical structural domain. The region corresponding to the important unstructured junction region linking helix C' to the first structural domain in alphaI-spectrin was clearly structured. On the basis of the published model for aligning helices A', B', and C', important interactions among residues in helix C' of alphaI- and alphaII-spectrin and helices A' and B' of betaI- and betaII-spectrin are identified, suggesting similar coiled coil helical bundling for spectrin I and II in forming tetramers. The differences in affinity are likely due to the differences in the conformation of the junction regions. Equilibrium dissociation constants of spin-labeled alphaII and betaI complexes from ITC measurements indicate that residues 15, 19, 37, and 40 are functionally important residues in alphaII-spectrin. Interestingly, all four corresponding homologous residues in alphaI-spectrin (residues 24, 28, 46, and 49) have been reported to be clinically significant residues involved in hematological diseases.
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Affiliation(s)
- Qufei Li
- Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, MC 111, Chicago, Illinois 60607
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Nilson DG, Sabatino DE, Bodine DM, Gallagher PG. Major erythrocyte membrane protein genes in EKLF-deficient mice. Exp Hematol 2006; 34:705-12. [PMID: 16728274 DOI: 10.1016/j.exphem.2006.02.018] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2006] [Revised: 02/16/2006] [Accepted: 02/21/2006] [Indexed: 11/18/2022]
Abstract
OBJECTIVES Mice deficient in the transcription factor erythroid Krüppel-like factor, KLF1 (EKLF) die approximately 14.5 days postcoitum of anemia, attributed to decreased expression of the beta-globin gene. The objectives of this study were to rescue EKLF-deficient embryos with mice expressing gamma-globin from beta-spectrin or ankyrin promoters and to characterize expression of the major erythrocyte membrane genes in EKLF-deficient cells. METHODS Transgenic beta-spectrin/gamma-globin or ankyrin/gamma-globin mice were bred onto EKLF-deficient and wild-type backgrounds. Animals were genotyped, gamma-globin mRNA levels measured, and hemoglobin electrophoresis performed. Steady-state mRNA levels and transcriptional rates of the major erythrocyte membrane protein genes were assayed. RESULTS beta-spectrin/gamma-globin or ankyrin/gamma-globin mice on EKLF-deficient and wild-type backgrounds had identical levels of gamma-globin mRNA, indicating EKLF-independence of these promoters. gamma-Globin expression improved globin chain imbalance, but hemolysis was not improved and no live-born EKLF-deficient/(A)gamma-globin mice were obtained. Circulating erythroid cells from EKLF-deficient/(A)gamma-globin embryos exhibited hemolysis reminiscent of that seen in patients with severe erythrocyte membrane defects. Levels of beta-spectrin, ankyrin, and band 3 mRNA, but not alpha-spectrin, were decreased in EKLF-deficient fetal liver RNA. In a run-on assay, levels of transcription of the ankyrin and band 3 genes were decreased in EKLF-deficient fetal liver nuclei. CONCLUSIONS These results indicate that the EKLF-responsive regions of the ankyrin and beta-spectrin genes are outside their promoters and that EKLF is necessary for full transcriptional activity of the ankyrin and band 3 genes; the results also provide additional evidence that defects in addition to beta-globin deficiency, including an abnormal erythrocyte membrane, contribute to the anemia and embryonic lethality in EKLF-deficient mice.
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Affiliation(s)
- Douglas G Nilson
- Hematopoiesis Section, Genetics and Molecular Biology Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
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Gallagher PG, Nilson DG, Wong C, Weisbein JL, Garrett-Beal LJ, Eber SW, Bodine DM. A dinucleotide deletion in the ankyrin promoter alters gene expression, transcription initiation and TFIID complex formation in hereditary spherocytosis. Hum Mol Genet 2005; 14:2501-9. [PMID: 16037067 DOI: 10.1093/hmg/ddi254] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Ankyrin defects are the most common cause of hereditary spherocytosis (HS). In some HS patients, mutations in the ankyrin promoter have been hypothesized to lead to decreased ankyrin mRNA synthesis. The ankyrin erythroid promoter is a member of the most common class of mammalian promoters which lack conserved TATA, initiator or other promoter cis elements and have high G+C content, functional Sp1 binding sites and multiple transcription initiation sites. We identified a novel ankyrin gene promoter mutation, a TG deletion adjacent to a transcription initiation site, in a patient with ankyrin-linked HS and analyzed its effects on ankyrin expression. In vitro, the mutant promoter directed decreased levels of gene expression, altered transcription initiation site utilization and exhibited defective binding of TATA-binding protein (TBP) and TFIID complex formation. In a transgenic mouse model, the mutant ankyrin promoter led to abnormalities in gene expression, including decreased expression of a reporter gene and altered transcription initiation site utilization. These data indicate that the mutation alters ankyrin gene transcription and contributes to the HS phenotype by decreasing ankyrin gene synthesis via disruption of TFIID complex interactions with the ankyrin core promoter. These studies support the model that in promoters that lack conserved cis elements, the TFIID complex directs preinitiation complex formation at specific sites in core promoter DNA and provide the first evidence that disruption of TBP binding and TFIID complex formation in this type of promoter leads to alterations in start site utilization, decreased gene expression and a disease phenotype in vivo.
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Affiliation(s)
- Patrick G Gallagher
- Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06520-8064, USA.
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Sumandea CA, Fung LWM. Mutational effects at the tetramerization site of nonerythroid alpha spectrin. ACTA ACUST UNITED AC 2005; 136:81-90. [PMID: 15893590 DOI: 10.1016/j.molbrainres.2005.01.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2004] [Revised: 11/18/2004] [Accepted: 01/08/2005] [Indexed: 10/25/2022]
Abstract
Spectrin, a prominent cytoskeletal protein, exerts its fundamental role in cellular function by forming a sub-membrane filamentous network. An essential aspect of spectrin network formation is the tetramerization of spectrin alphabeta heterodimers. We used laboratory methods, the yeast two-hybrid system and random mutagenesis, to investigate, for the first time, effects of amino acid mutations on tetramerization of nonerythroid (brain) spectrin (fodrin). Based on high sequence homology with erythroid spectrin, we assume the putative tetramerization region of nonerythroid alpha-spectrin at the N-terminal region. We introduced mutations in the region consisting of residues 1-45 and studied mutational effects on spectrin alphabeta association to form tetramers. We detected single, double, and triple mutations involving 24 residues in this region. These amino acid mutations of nonerythroid alpha-spectrin exhibit full, partial, or no effect on the association with nonerythroid beta-spectrin. Single amino acid mutations in the region of residues 1-9 (D2Y, G5V, V6D, and V8M) did not affect the association. However, seven single mutations (I15F, I15N, R18G, V22D, R25P, Y26N, and R28P) affected the alphabeta association. These mutations were clustered in the region predicted by sequence alignment to be crucial in nonerythroid alpha-spectrin for tetramerization, a region that spanned residues 12-36, corresponding to the partial domain Helix C' (residues 21-45) in erythroid alpha-spectrin. In addition, two other mutations, one upstream and one downstream of this region at positions 10 (E10D) and 37 (R37P), also affected the alphabeta association. Our results implied nonerythroid alpha-spectrin partial domain helix may be longer than Helix C' (residues 21-45 and a total of 25 residues) in erythroid alpha-spectrin and spanned at least residues 10-37. It is interesting to note that seven out of these nine single mutations (I15F, I15N, R18G, V22D, R25P, Y26N, R37P) were at the a, d, e or g heptad positions based on sequence alignment with erythroid alpha-spectrin. Four of the mutated residues (I15, R18, V22, R25) are conserved in both erythroid and nonerythroid spectrin. These positions were previously identified as hot spots in erythroid alpha-spectrin that lead to severe hematological symptoms. This study clearly demonstrated that single mutation in a region predicted to be critical functionally in nonerythroid alpha-spectrin indeed leads to functional abnormalities and may lead to neurological disorders.
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Affiliation(s)
- Claudia A Sumandea
- Loyola University of Chicago, Department of Chemistry, 6525 N Sheridan Road, Chicago, IL 60626, USA
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Cameron HS, Somaschini M, Carrera P, Hamvas A, Whitsett JA, Wert SE, Deutsch G, Nogee LM. A common mutation in the surfactant protein C gene associated with lung disease. J Pediatr 2005; 146:370-5. [PMID: 15756222 DOI: 10.1016/j.jpeds.2004.10.028] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE To determine the contribution of the surfactant protein C (SP-C) I73T mutation to lung disease. STUDY DESIGN Genomic DNA was obtained from 116 children with interstitial lung disease (ILD) or chronic lung disease of unclear cause and from 166 control subjects and was screened for the I73T mutation using an allele-specific polymerase chain reaction assay. RESULTS The I73T mutation was found on 7 of 232 SP-C alleles from 7 unrelated children with ILD but was not found on 332 control SP-C alleles ( P < .01, Fisher exact test). The I73T mutation segregated with lung disease in one kindred with familial ILD. The I73T mutation was found in an asymptomatic parent from two different families with affected children consistent with variable penetrance, but it was not found in either asymptomatic parent of two other unrelated affected children consistent with a de novo mutation. Analysis of single nucleotide polymorphisms indicated diverse genetic backgrounds of the I73T alleles. Immunohistochemical analysis of lung tissue from an infant with the I73T mutation demonstrated normal staining patterns for proSP-B, SP-B, and proSP-C. CONCLUSIONS These findings support the hypothesis that the I73T mutation predisposes to or causes lung disease.
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Affiliation(s)
- H Scott Cameron
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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