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Molina MF, Pio MG, Scheps KG, Adrover E, Abelleyro MM, Targovnik HM, Rivolta CM. Curating the gnomAD database: Report of novel variants in the thyroid peroxidase gene using in silico bioinformatics algorithms and a literature review. Mol Cell Endocrinol 2022; 558:111748. [PMID: 35995307 DOI: 10.1016/j.mce.2022.111748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 07/31/2022] [Accepted: 08/01/2022] [Indexed: 12/15/2022]
Abstract
Thyroid peroxidase (TPO) is a membrane-bound glycoprotein located at the apical side of the thyroid follicular cells that catalyzes both iodination and coupling of iodotyrosine residues within the thyroglobulin molecule, leading to the synthesis of thyroid hormone. Variants in TPO cause congenital hypothyroidism (CH) by iodide organification defect and are commonly inherited in an autosomal recessive fashion. In the present work, we report a detailed population analysis and bioinformatic prediction of the TPO variants indexed in the Genome Aggregation Database (gnomAD) v2.1.1. The proportion of missense cysteine variants and nonsense, frameshift, and splice acceptor/donor variants were analyzed in each ethnic group (European (Non-Finnish), European (Finnish), African/African Americans, Latino/Admixed American, East Asian, South Asian, Ashkenazi Jewish, Other). The results showed a clear predominance of frameshift variants in the East Asian (82%) and European (Finnish) (75%) population, whereas the splice site variants predominate in African/African Americans (99.46%), Other (96%), Latino/Admixed American (94%), South Asian (86%), European (Non-Finnish) (56%) and Ashkenazi Jewish (56%) populations. The analysis of the distribution of the variants indexed in gnomAD v2.1.1 database revealed that most missense variants identified in the An peroxidase domain map in exon 8, followed by exons 11, 7 and 9, and finally in descending order by exons 10, 6, 12 and 5. In total, 183 novel TPO variants were described (13 missense cysteine's variants, 158 missense variants involving the An peroxidase domain and 12 splicing acceptor or donor sites variants) which were not reported in the literature and that would have deleterious effects on prediction programs. In the gnomAD v2.1.1 population, the estimated prevalence of heterozygous carriers of the potentially damaging variants was 1:77. In conclusion, we provide an updated and curated reference source of new TPO variants for application in clinical diagnosis and genetic counseling. Also, this work contributes to elucidating the molecular basis of CH associated with TPO defects.
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Affiliation(s)
- Maricel F Molina
- Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología, Biotecnología y Genética/Cátedra de Genética, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Inmunología, Genética y Metabolismo (INIGEM), Buenos Aires, Argentina
| | - Mauricio Gomes Pio
- Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología, Biotecnología y Genética/Cátedra de Genética, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Inmunología, Genética y Metabolismo (INIGEM), Buenos Aires, Argentina
| | - Karen G Scheps
- Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología, Biotecnología y Genética/Cátedra de Genética, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Inmunología, Genética y Metabolismo (INIGEM), Buenos Aires, Argentina
| | - Ezequiela Adrover
- Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología, Biotecnología y Genética/Cátedra de Genética, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Inmunología, Genética y Metabolismo (INIGEM), Buenos Aires, Argentina
| | - Miguel M Abelleyro
- CONICET-Academia Nacional de Medicina, Instituto de Medicina Experimental (IMEX), Buenos Aires, Argentina
| | - Héctor M Targovnik
- Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología, Biotecnología y Genética/Cátedra de Genética, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Inmunología, Genética y Metabolismo (INIGEM), Buenos Aires, Argentina
| | - Carina M Rivolta
- Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología, Biotecnología y Genética/Cátedra de Genética, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Inmunología, Genética y Metabolismo (INIGEM), Buenos Aires, Argentina.
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Cangul H, Aydin BK, Bas F. A Homozygous TPO Gene Duplication (c.1184_1187dup4) Causes Congenital Hypothyroidism in Three Siblings Born to a Consanguineous Family. J Pediatr Genet 2016; 4:194-8. [PMID: 27617131 DOI: 10.1055/s-0035-1565268] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 04/16/2015] [Indexed: 10/22/2022]
Abstract
Congenital hypothyroidism (CH) is the most common neonatal endocrine disease, and germ-line mutations in the TPO gene cause the inherited form of the disease. Our aim in this study was to determine the genetic basis of congenital hypothyroidism in three affected children coming from a consanguineous Turkish family. Because CH is usually inherited in autosomal recessive manner in consanguineous/multicase families, we adopted a two-stage strategy of genetic linkage studies and targeted sequencing of the candidate genes. First, we investigated the potential genetic linkage of the family to any known CH locus, using microsatellite markers, and then screened for mutations in linked-gene by conventional sequencing. The family showed potential linkage to the TPO gene and we detected a homozygous duplication (c.1184_1187dup4) in all cases. The mutation segregated with disease status in the family. This study confirms the pathogenicity of the c.1184_1187dup4 mutation in the TPO gene and helps establish a genotype/phenotype correlation associated with this mutation. It also highlights the importance of molecular genetic studies in the definitive diagnosis and accurate classification of CH.
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Affiliation(s)
- Hakan Cangul
- Department of Medical Genetics, Istanbul Medipol University, International School of Medicine, Istanbul, Turkey; Centre for Rare Diseases and Personalised Medicine, University of Birmingham, School of Clinical and Experimental Medicine, Birmingham, United Kingdom
| | - Banu K Aydin
- Pediatric Endocrinology Unit, Istanbul Faculty of Medicine, Istanbul University, Turkey
| | - Firdevs Bas
- Pediatric Endocrinology Unit, Istanbul Faculty of Medicine, Istanbul University, Turkey
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Sriphrapradang C, Thewjitcharoen Y, Chanprasertyothin S, Nakasatien S, Himathongkam T, Trachoo O. A Novel Mutation in Thyroid Peroxidase Gene Causing Congenital Goitrous Hypothyroidism in a German-Thai Patient. J Clin Res Pediatr Endocrinol 2016; 8:241-5. [PMID: 26761947 PMCID: PMC5096484 DOI: 10.4274/jcrpe.2503] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Thyroid dyshormonogenesis is responsible for 10-15% of all cases of congenital hypothyroidism and is usually inherited. We report a 26-year-old German-Thai male with congenital hypothyroidism caused by a compound heterozygous mutation in the thyroid peroxidase (TPO) gene. He was diagnosed with congenital goitrous hypothyroidism at 4 months of age and had been treated with levothyroxine replacement therapy. His goiter size had increased due to poor compliance to treatment. Ultrasonography of the thyroid gland showed a pattern suspicious for malignancy. The patient later underwent near-total thyroidectomy. Pathologic examination results were consistent with a multinodular goiter and no malignancy. Genetic analyses by direct sequencing of the entire exons and flanking regions of the TPO gene were performed in the index case and family members. The analyses revealed a compound heterozygote of novel TPO mutation of c.1727C>T in exon 10 resulting in amino acid substitution (p.Ala576Val) and c.2268_2269insT in exon 13 causing a frameshift mutation which introduced a stop codon after the insertion site. The latter has been reported in Chinese subjects. However, there is no previous report of c.1727C>T mutation in the literature. We found the allele contained a novel exon 10 mutation inherited from the patient's German mother and an exon 13 mutation from his Thai father. Analysis using two bioinformatic software programs indicated that this variant was likely to cause damage in the resulting protein molecule. The present report emphasizes the importance of regular follow-up and patient compliance to levothyroxine replacement in patients with goitrous congenital hypothyroidism to avoid prolonged stimulation of thyroid tissue by thyroid-stimulating hormone.
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Affiliation(s)
- Chutintorn Sriphrapradang
- Mahidol University Faculty of Medicine, Ramathibodi Hospital, Clinic of Medicine, Bangkok, Thailand, Phone: +66 2 201 1647 E-mail:
| | - Yotsapon Thewjitcharoen
- Theptarin Hospital, Diabetes and Thyroid Center, Bangkok, Thailand
,
Contributed equally to this work
| | | | | | | | - Objoon Trachoo
- Mahidol University Faculty of Medicine, Ramathibodi Hospital, Clinic of Medicine, Bangkok, Thailand
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O'Neill S, Brault J, Stasia MJ, Knaus UG. Genetic disorders coupled to ROS deficiency. Redox Biol 2015; 6:135-156. [PMID: 26210446 PMCID: PMC4550764 DOI: 10.1016/j.redox.2015.07.009] [Citation(s) in RCA: 118] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 07/15/2015] [Accepted: 07/16/2015] [Indexed: 12/24/2022] Open
Abstract
Maintaining the redox balance between generation and elimination of reactive oxygen species (ROS) is critical for health. Disturbances such as continuously elevated ROS levels will result in oxidative stress and development of disease, but likewise, insufficient ROS production will be detrimental to health. Reduced or even complete loss of ROS generation originates mainly from inactivating variants in genes encoding for NADPH oxidase complexes. In particular, deficiency in phagocyte Nox2 oxidase function due to genetic variants (CYBB, CYBA, NCF1, NCF2, NCF4) has been recognized as a direct cause of chronic granulomatous disease (CGD), an inherited immune disorder. More recently, additional diseases have been linked to functionally altered variants in genes encoding for other NADPH oxidases, such as for DUOX2/DUOXA2 in congenital hypothyroidism, or for the Nox2 complex, NOX1 and DUOX2 as risk factors for inflammatory bowel disease. A comprehensive overview of novel developments in terms of Nox/Duox-deficiency disorders is presented, combined with insights gained from structure-function studies that will aid in predicting functional defects of clinical variants.
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Affiliation(s)
- Sharon O'Neill
- Conway Institute, University College Dublin, Dublin, Ireland
| | - Julie Brault
- Université Grenoble Alpes, TIMC-IMAG Pôle Biologie, CHU de Grenoble, Grenoble, France; CGD Diagnosis and Research Centre, Pôle Biologie, CHU de Grenoble, Grenoble, France
| | - Marie-Jose Stasia
- Université Grenoble Alpes, TIMC-IMAG Pôle Biologie, CHU de Grenoble, Grenoble, France; CGD Diagnosis and Research Centre, Pôle Biologie, CHU de Grenoble, Grenoble, France
| | - Ulla G Knaus
- Conway Institute, University College Dublin, Dublin, Ireland.
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Cangül H, Doğan M, Üstek D. A Homozygous Nonsense Thyroid Peroxidase Mutation (R540X) Consistently Causes Congenital Hypothyroidism in Two Siblings Born to a Consanguineous Family. J Clin Res Pediatr Endocrinol 2015; 7:323-8. [PMID: 26777044 PMCID: PMC4805212 DOI: 10.4274/jcrpe.1920] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
OBJECTIVE Congenital hypothyroidism (CH) is the most common neonatal endocrine disorder, and mutations in the thyroid peroxidase (TPO) gene have been reported to cause the disease. Our aim in this study was to determine the genetic basis of CH in two affected children coming from a consanguineous family. METHODS First, we investigated the potential genetic linkage of the family to any known CH locus using microsatellite markers and then screened for mutations in the linked gene by Sanger sequencing. By using next-generation sequencing, we also checked if any other mutation was present in the remaining 10 causative CH genes. RESULTS The family showed potential linkage to the TPO gene, and we detected a homozygous nonsense mutation (R540X) in both cases. The two patients had total iodide organification defect (TIOD). Both the microsatellite marker haplotypes and the mutation segregated with the disease status in the family, i.e. all healthy subjects were either heterozygous carriers or homozygous wild-type, confirming the pathogenic nature of the mutation. Neither was the mutation present in any of the 400 control chromosomes nor were there any other mutations in the remaining causative CH genes. CONCLUSION This study proves the pathogenicity of R540X mutation and demonstrates the strong genotype/phenotype correlation associated with this mutation. It also highlights the power of working with familial cases in revealing the molecular basis of CH and in establishing accurate genotype/phenotype relationships associated with disease causing mutations.
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Affiliation(s)
- Hakan Cangül
- Medipol University International Faculty of Medicine, Department of Medical Genetics, İstanbul, Turkey Phone: +90 216 681 51 00 E-mail:
| | - Murat Doğan
- Yüzüncü Yıl University Faculty of Medicine, Division of Pediatric Endocrinology, Van, Turkey
| | - Duran Üstek
- Medipol University International Faculty of Medicine, Department of Medical Genetics, İstanbul, Turkey
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Bougacha-Elleuch N, Charfi N, Miled N, Bouhajja H, Belguith N, Mnif M, Jaurge P, Chikhrouhou N, Ayadi H, Hachicha M, Abid M. Segregation of S292F TPO gene mutation in three large Tunisian families with thyroid dyshormonogenesis: evidence of a founder effect. Eur J Pediatr 2015; 174:1491-501. [PMID: 25968604 DOI: 10.1007/s00431-015-2550-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 04/10/2015] [Accepted: 04/14/2015] [Indexed: 11/28/2022]
Abstract
UNLABELLED We aimed to identify causal mutation(s) in 13 patients with thyroid dyshormonogenesis (TD) from three consanguineous Tunisian families. A 12-year clinical follow-up showed phenotypic variability ranging from the presence to the absence of goiter, sensorineural deafness, and mental retardation. Genetic analysis using microsatellite markers within two candidate genes (TPO and PDS) gave evidence of linkage with the TPO gene. Sequencing of its 17 exons and their flanking intron-exon junctions revealed the previously described c.875C>T (p.S292F) mutation in homozygous state. No additional mutations were found in either a 900 bp of the TPO gene promoter or PDS gene. In silico analysis showed that p.S292F mutation might reduce the catalytic cavity of the TPO which would restrict access of a potential substrate to the catalytic pocket. Using 4SNPs and one microsatellite marker in the TPO gene, an associated haplotype: G-C-G-G-214 was found, giving evidence of a founder mutation. CONCLUSION This is the first description of a TD causing mutation in Tunisia and thus may help to develop a genetic screening protocol for congenital hypothyroidism in the studied region. Although structural modeling suggested a pathogenic effect of this mutation, functional studies are needed. Additional causing and/or modifier genes, together with late diagnosis could explain the clinical variability observed in our patients.
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Affiliation(s)
- Noura Bougacha-Elleuch
- Unité Cibles pour le Diagnostic et la Thérapie, Centre de Biotechnologie Sfax, BP 1177, 3018, Sfax, Tunisia.
| | - Nadia Charfi
- Service d'Endocrinologie, CHU Hédi Chaker, Sfax, Tunisia
| | - Nabil Miled
- Laboratoire de Biochimie et de Génie Enzymatique des Lipases, Ecole Nationale d'Ingénieurs de Sfax, Route Soukra BP W, Sfax, Tunisia
| | - Houda Bouhajja
- Unité Cibles pour le Diagnostic et la Thérapie, Centre de Biotechnologie Sfax, BP 1177, 3018, Sfax, Tunisia
| | - Neila Belguith
- Laboratoire de Génétique Moléculaire Humaine, Faculté de Médecine, Sfax, Tunisia
| | - Mouna Mnif
- Service d'Endocrinologie, CHU Hédi Chaker, Sfax, Tunisia
| | - Paula Jaurge
- Unidade de Genética Molecular, Centro de Genética Médica Doutor Jacinto Magalhães, Centro Hospitalar do Porto, Porto, Portugal.,Unit for Multidisciplinary Research in Biomedicine, UMIB, ICBAS-UP, Porto, Portugal
| | | | - Hammadi Ayadi
- Unité Cibles pour le Diagnostic et la Thérapie, Centre de Biotechnologie Sfax, BP 1177, 3018, Sfax, Tunisia
| | | | - Mohamed Abid
- Service d'Endocrinologie, CHU Hédi Chaker, Sfax, Tunisia
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Cangül H, Demir K, Babayiğit HÖ, Abacı A, Böber E. The Missense Alteration A5T of the Thyroid Peroxidase Gene is Pathogenic and Associated with Mild Congenital Hypothyroidism. J Clin Res Pediatr Endocrinol 2015; 7:238-41. [PMID: 26831560 PMCID: PMC4677561 DOI: 10.4274/jcrpe.2017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Congenital hypothyroidism (CH) occurs with a prevalence of approximately 1:4000 live births. Defects of thyroid hormone synthesis account for 15-20% of these cases. Thyroid peroxidase (TPO) gene is the most common cause for dyshormonogenesis. So far, more than 60 mutations in the TPO gene have been described, resulting in a variable decrease in TPO bioactivity. We present an 8-day-old male with mild CH who was identified to have a G to A transition in the fifth codon of the TPO gene (c.13G>A; p.Ala5Thr). The unaffected family members were heterozygous carriers of the mutation, whereas 400 healthy individuals of the same ethnic background did not have the mutation. Mutation analysis of 11 known causative CH genes and 4 of our own strong candidate genes with next-generation sequencing revealed no mutations in the patient nor in any other family members. The results of in silico functional analyses indicated partial loss-of-function (LOF) in the resulting enzyme molecule due to mutation. The patient's clinical finding s were consistent with the effect of this partial LOF of the mutation. In conclusion, we strongly believe that A5T alteration in the TPO gene is actually pathogenic and suggest that it should be classified as a mutation.
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Affiliation(s)
- Hakan Cangül
- Medipol University Faculty of Medicine, Department of Medical Genetics, İstanbul, Turkey Phone: +90 216 681 51 00 E-mail:
| | - Korcan Demir
- Dokuz Eylül University Faculty of Medicine, Department of Pediatric Endocrinology, İzmir, Turkey
| | - H. Ömür Babayiğit
- Dokuz Eylül University Faculty of Medicine, Department of Pediatrics, İzmir, Turkey
| | - Ayhan Abacı
- Dokuz Eylül University Faculty of Medicine, Department of Pediatric Endocrinology, İzmir, Turkey
| | - Ece Böber
- Dokuz Eylül University Faculty of Medicine, Department of Pediatric Endocrinology, İzmir, Turkey
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