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Westphal DS, Hauser M, Beckmann BM, Wolf CM, Hessling G, Oberhoffer-Fritz R, Wacker-Gussmann A. Fetal Bradycardia Caused by Monogenic Disorders-A Review of the Literature. J Clin Med 2022; 11:jcm11236880. [PMID: 36498454 PMCID: PMC9741304 DOI: 10.3390/jcm11236880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 11/03/2022] [Accepted: 11/18/2022] [Indexed: 11/24/2022] Open
Abstract
Introduction: The standard obstetric definition of fetal bradycardia is a sustained fetal heart rate < 110 bpm over at least 10 min. Fetal bradycardia can be the first and only prenatal presentation of a heart disease. We present an overview on different genetic disorders that should be taken into consideration in case of diagnosed fetal bradycardia. Methods: A literature review was conducted using a PubMed- and OMIM-based search for monogenetic disorders causing fetal bradycardia in September 2022. Results: The review on the literature identified nine monogenic diseases that could lead to fetal bradycardia. Four of these disorders can be associated with extracardiac findings. Discussion: Genetic testing should be considered in cases with fetal bradycardia, especially in cases of additional extracardiac findings. Broad sequencing techniques and improved prenatal phenotyping could help to establish a diagnosis in an increasing number of cases.
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Affiliation(s)
- Dominik S. Westphal
- Department of Internal Medicine I, Klinikum Rechts der Isar, School of Medicine and Health, Technical University Munich, 81675 Munich, Germany
- Institute of Human Genetics, Klinikum Rechts der Isar, School of Medicine and Health, Technical University Munich, 81675 Munich, Germany
- Correspondence:
| | | | - Britt-Maria Beckmann
- Institute of Legal Medicine, University Hospital Frankfurt, Goethe University, 60596 Frankfurt, Germany
| | - Cordula M. Wolf
- DZHK (German Centre for Cardiovascular Research), Partner Site Munich Heart Alliance, 80802 Munich, Germany
- Department of Congenital Heart Defects and Pediatric Cardiology, German Heart Center Munich, School of Medicine and Health, Technical University Munich, 80636 Munich, Germany
| | - Gabriele Hessling
- Department of Congenital Heart Defects and Pediatric Cardiology, German Heart Center Munich, School of Medicine and Health, Technical University Munich, 80636 Munich, Germany
| | - Renate Oberhoffer-Fritz
- Department of Congenital Heart Defects and Pediatric Cardiology, German Heart Center Munich, School of Medicine and Health, Technical University Munich, 80636 Munich, Germany
- Institute of Preventive Pediatrics, TUM Department of Sport and Health Sciences, Technical University Munich, 80992 Munich, Germany
| | - Annette Wacker-Gussmann
- Department of Congenital Heart Defects and Pediatric Cardiology, German Heart Center Munich, School of Medicine and Health, Technical University Munich, 80636 Munich, Germany
- Institute of Preventive Pediatrics, TUM Department of Sport and Health Sciences, Technical University Munich, 80992 Munich, Germany
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2
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van Minkelen R, van Bever Y, Kromosoeto J, Withagen-Hermans C, Nieuwlaat A, Halley D, van den Ouweland A. A clinical and genetic overview of 18 years neurofibromatosis type 1 molecular diagnostics in the Netherlands. Clin Genet 2013; 85:318-27. [DOI: 10.1111/cge.12187] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 05/03/2013] [Accepted: 05/03/2013] [Indexed: 11/26/2022]
Affiliation(s)
- R. van Minkelen
- Department of Clinical Genetics; Erasmus Medical Center; Rotterdam The Netherlands
| | - Y. van Bever
- Department of Clinical Genetics; Erasmus Medical Center; Rotterdam The Netherlands
| | - J.N.R. Kromosoeto
- Department of Clinical Genetics; Erasmus Medical Center; Rotterdam The Netherlands
| | | | - A. Nieuwlaat
- Department of Clinical Genetics; Erasmus Medical Center; Rotterdam The Netherlands
| | - D.J.J. Halley
- Department of Clinical Genetics; Erasmus Medical Center; Rotterdam The Netherlands
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3
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Feliciano DM, Lin TV, Hartman NW, Bartley CM, Kubera C, Hsieh L, Lafourcade C, O'Keefe RA, Bordey A. A circuitry and biochemical basis for tuberous sclerosis symptoms: from epilepsy to neurocognitive deficits. Int J Dev Neurosci 2013; 31:667-78. [PMID: 23485365 DOI: 10.1016/j.ijdevneu.2013.02.008] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 02/15/2013] [Accepted: 02/18/2013] [Indexed: 01/17/2023] Open
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant monogenetic disorder that is characterized by the formation of benign tumors in several organs as well as brain malformations and neuronal defects. TSC is caused by inactivating mutations in one of two genes, TSC1 and TSC2, resulting in increased activity of the mammalian Target of Rapamycin (mTOR). Here, we explore the cytoarchitectural and functional CNS aberrations that may account for the neurological presentations of TSC, notably seizures, hydrocephalus, and cognitive and psychological impairments. In particular, recent mouse models of brain lesions are presented with an emphasis on using electroporation to allow the generation of discrete lesions resulting from loss of heterozygosity during perinatal development. Cortical lesions are thought to contribute to epileptogenesis and worsening of cognitive defects. However, it has recently been suggested that being born with a mutant allele without loss of heterozygosity and associated cortical lesions is sufficient to generate cognitive and neuropsychiatric problems. We will thus discuss the function of mTOR hyperactivity on neuronal circuit formation and the potential consequences of being born heterozygous on neuronal function and the biochemistry of synaptic plasticity, the cellular substrate of learning and memory. Ultimately, a major goal of TSC research is to identify the cellular and molecular mechanisms downstream of mTOR underlying the neurological manifestations observed in TSC patients and identify novel therapeutic targets to prevent the formation of brain lesions and restore neuronal function.
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Affiliation(s)
- David M Feliciano
- Department of Neurosurgery, Yale University School of Medicine, New Haven, CT, USA; Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
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4
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Abstract
Tuberous Sclerosis Complex (TSC) was first described in the late 1800s as a relative of neurofibromatosis, but it has since been identified as a discrete disorder. Patients with TSC typically present with facial adenomas, seizure disorder, and a developmental disability. The syndrome is caused by mutations in either chromosomes 9 or 16, both of which code for cell development and maturation. This case report describes the unique findings of TSC, and suggests areas for future study. By understanding the dental and medical implications of TSC, early intervention may vastly improve a patient's overall quality of life.
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Affiliation(s)
- Allen Wong
- Hospital Dentistry Program, Department of Dental Practice, University of the Pacific Arthur, A. Dugoni School of Dentistry, San Francisco, California, USA.
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5
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Tai HC, Lin JW, Wang YH, Eng HL, Lu HI, Liu YW, Huang CC. Pulmonary lymphangioleiomyomatosis followed by a localized retroperitoneal lymphangioleiomyoma. APMIS 2007; 114:821-4. [PMID: 17078865 DOI: 10.1111/j.1600-0463.2006.apm_489.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Lymphangioleiomyomatosis is a rare disease that affects females of reproductive age. Microscopically, it is characterized by abnormal proliferation of immature smooth muscle-like cells that grow diffusely in the lung. Extrapulmonary manifestations in the mediastinum, peritoneum and pelvic lymph nodes are uncommon. We here describe a patient who initially presented with pulmonary lymphangioleiomyomatosis and subsequently developed a localized retroperitoneal mass. Pathologic examination showed that the mass was a lymphangioleiomyoma. The result of the immunohistochemical study was the same as that for the pulmonary lesion. It is therefore suggested that metastatic lymphangioleiomyoma should be included in the differential diagnosis in the patient with pulmonary lymphangioleiomyomatosis presenting with an extrapulmonary lesion.
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Affiliation(s)
- Hui-Chun Tai
- Department of Pathology, Changhua Christian Hospital, Changhua, Taiwan
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6
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Milunsky A, Shim SH, Ito M, Jaekle RK, Bassett LL, Brumund MR, Milunsky JM. Precise prenatal diagnosis of tuberous sclerosis by sequencing the TSC2 gene. Prenat Diagn 2005; 25:582-5. [PMID: 16032769 DOI: 10.1002/pd.1197] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
BACKGROUND The presumptive prenatal diagnosis of tuberous sclerosis (TSC) previously depended upon fetal imaging. Cloning of the two TSC genes (TSC1 and TSC2) now enables precise molecular diagnosis by gene sequencing. We used this approach for the prenatal diagnosis of a fetus showing multiple intracardiac tumors. METHODS DNA extracted from cultivated amniotic fluid cells underwent sequencing of all coding regions and exon-intron boundaries of the TSC1 and TSC2 genes. RESULTS A mutation (R611Q) was found in exon 16 of the TSC2 gene. Thus far, neither clinically unaffected parents has provided blood samples for mutation analysis. CONCLUSION For the first time, mutation analysis of a TSC gene enabled a precise prenatal diagnosis.
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Affiliation(s)
- Aubrey Milunsky
- Center for Human Genetics, Boston University School of Medicine, Boston, MA 02118, USA.
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7
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Ali M, Girimaji SC, Markandaya M, Shukla AK, Sacchidanand S, Kumar A. Mutation and polymorphism analysis of TSC1 and TSC2 genes in Indian patients with tuberous sclerosis complex. Acta Neurol Scand 2005; 111:54-63. [PMID: 15595939 DOI: 10.1111/j.1600-0404.2004.00366.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To find the mutation and polymorphism spectrum of TSC1 and TSC2 genes in patients affected with tuberous sclerosis complex from the Indian population. MATERIAL AND METHODS All coding exons and promoter regions of both TSC genes were screened for mutations and polymorphisms in 24 TSC families using polymerase chain reaction-single strand conformation polymorphism and DNA sequencing techniques. RESULTS A single previously known mutation, c.2111_2112delAT was identified in the TSC1 gene. A total of 11 mutations were identified in the TSC2 gene. Of these, seven mutations, c.137_138delGA, c.2070delC, c.2087_2088insAA, c.3080T>C (p.L1027P), c.648+1G>A, c.3131+1G>A and c.5034C>G were novel. The remaining four mutations, c.4544_4547delACAA, c.1941_1942insT, c.1831C>T (p.R611W) and c.1832G>A (p.R611Q) had been reported previously in other populations. The novel mutation, c.137_138delGA was predicted to result in the production of a very small tuberin protein of 64 amino acids lacking all seven functional domains. In addition, we also detected three and 10 polymorphisms in the TSC1 and TSC2 genes respectively. DNA sequence analysis of promoter regions of both TSC genes in 24 families did not show any variation. CONCLUSIONS This is the first molecular genetic study of TSC in an Indian population. A total of 12 mutations were detected in 24 Indian TSC families in TSC genes. All except one mutation were detected in the TSC2 gene. No variation was found in the promoter regions of either gene. As observed in the western and Japanese populations, the mutations were scattered across the TSC2 gene.
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Affiliation(s)
- M Ali
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, India
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8
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Zhang F, Jetten AM. Genomic structure of the gene encoding the human GLI-related, Krüppel-like zinc finger protein GLIS2. Gene 2001; 280:49-57. [PMID: 11738817 DOI: 10.1016/s0378-1119(01)00764-8] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In this study, we describe the sequence and genomic structure of the human GLIS2 gene, encoding a new member of the Krüppel-like zinc finger protein family. GLIS2 is a relatively proline-rich, basic protein of 55.7 kDa in size. It contains five tandem Cys(2)-His(2) zinc finger motifs consisting of the consensus sequence X-Cys-X(2,4)-Cys-X(12,15)-His-X(3,4)-His-X. The sequence of the zinc finger domain exhibits highest homology with those of members of the GLI and ZIC subfamilies of Krüppel-like proteins. The zinc finger domain of GLIS2 exhibits highest (58%) homology with that of GLI-1. The human GLIS2 gene consists of six exons and five introns, and spans more than 7.5 kb. Primer extension identified several putative transcription initiation sites. GLIS2 mRNA is most abundantly expressed in human kidney suggesting a role in the regulation of certain kidney functions. The GLIS2 gene maps to human chromosome 16p13.3, a locus implicated in several human kidney diseases. The sequence and structure of human GLIS2 will be useful tools to study the regulation of GLIS2 and its potential role in human disease.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- Blotting, Northern
- Cell Line
- Chromosome Mapping
- Chromosomes, Human, Pair 16/genetics
- Cloning, Molecular
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- DNA-Binding Proteins/genetics
- Evolution, Molecular
- Female
- Gene Expression
- Genes/genetics
- Humans
- Kruppel-Like Transcription Factors
- Molecular Sequence Data
- Phylogeny
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Sequence Alignment
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Tissue Distribution
- Transcription Initiation Site
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Affiliation(s)
- F Zhang
- Cell Biology Section, Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health Research, Triangle Park, NC 27709, USA
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9
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Cutando A, Gil JA, López J. Oral health management implications in patients with tuberous sclerosis. ORAL SURGERY, ORAL MEDICINE, ORAL PATHOLOGY, ORAL RADIOLOGY, AND ENDODONTICS 2000; 90:430-5. [PMID: 11027378 DOI: 10.1067/moe.2000.105766] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We report 6 cases of patients with tuberous sclerosis and concomitant dental pathosis. The multiple manifestations in tuberous sclerosis determine its impact on dental therapy. A lack of awareness of this condition may compound the possible side effects of dental treatment. Possible preventive measures by dentists are highlighted in this presentation. Medical evaluation and the control of risk factors in relation to general anesthesia and sedation are key considerations for the management of patients with tuberous sclerosis.
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Affiliation(s)
- A Cutando
- Dental School, Granada University, Spain
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10
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Beauchamp RL, Banwell A, McNamara P, Jacobsen M, Higgins E, Northrup H, Short P, Sims K, Ozelius L, Ramesh V. Exon scanning of the entire TSC2 gene for germline mutations in 40 unrelated patients with tuberous sclerosis. Hum Mutat 2000; 12:408-16. [PMID: 9829910 DOI: 10.1002/(sici)1098-1004(1998)12:6<408::aid-humu7>3.0.co;2-p] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Tuberous sclerosis complex (TSC) is a dominantly inherited multisystem disorder resulting in the development of hamartomatous growths in many organs. Genetic heterogeneity has been demonstrated linking the familial cases to either TSC1 at 9q34.3, or TSC2 at 16p13.3. About two-thirds of the TSC cases are sporadic and appear to represent new mutations. While both genes are thought to account for all familial cases, with each representing approximately 50% of the mutations, the proportion of sporadic cases with mutations in TSC1 and TSC2 is yet to be determined. We have examined the entire coding sequence of the TSC2 gene in 20 familial and 20 sporadic cases and identified a total of twenty-one mutations representing 50% and 55% of familial and sporadic cases respectively. Our rate of mutation detection is significantly higher than other published reports. Twenty out of 21 mutations are novel and include 6 missense, 6 nonsense, 5 frameshifts, 2 splice alterations, a 34 bp deletion resulting in abnormal splicing, and an 18 bp deletion which maintains the reading frame. The mutations are distributed throughout the coding sequence with no specific hot spots. There is no apparent correlation between mutation type and clinical severity of the disease. Our results document that at least 50% of sporadic cases arise from mutations in the TSC2 gene. The location of the mutations described here, particularly the missense events, should be valuable for further functional analysis of this tumor suppressor protein.
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Affiliation(s)
- R L Beauchamp
- Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown 02129, USA
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11
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Jones AC, Shyamsundar MM, Thomas MW, Maynard J, Idziaszczyk S, Tomkins S, Sampson JR, Cheadle JP. Comprehensive mutation analysis of TSC1 and TSC2-and phenotypic correlations in 150 families with tuberous sclerosis. Am J Hum Genet 1999; 64:1305-15. [PMID: 10205261 PMCID: PMC1377866 DOI: 10.1086/302381] [Citation(s) in RCA: 365] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Tuberous sclerosis (TSC [MIM 191090 and MIM 191100]) is an autosomal dominant disorder characterized by hamartomas in many organs. Two thirds of cases are sporadic and are thought to represent new mutations. TSC is caused by mutations affecting either of the presumed tumor-suppressor genes, TSC1 and TSC2. Both appear to function as tumor suppressors, because somatic loss or intragenic mutation of the corresponding wild-type allele is seen in the associated hamartomas. Here we report the first comprehensive mutation analysis of TSC1 and TSC2 in a cohort of 150 unrelated TSC patients and their families, using heteroduplex and SSCP analysis of all coding exons and using pulsed-field gel electrophoresis and conventional Southern blot analysis and long PCR to screen for large rearrangements. Mutations were characterized in 120 (80%) of the 150 cases, affecting TSC1 in 22 cases and TSC2 in 98 cases. TSC1 mutations were significantly underrepresented in sporadic cases (P=. 000185). Twenty-two patients had TSC2 missense mutations that were found predominantly in the GAP-related domain (eight cases) and in a small region encoded in exons 16 and 17, between nucleotides 1849 and 1859 (eight cases), consistent with the presence of residues performing key functions at these sites. In contrast, all TSC1 mutations were predicted to be truncating, consistent with a structural or adapter role for the encoded protein. Intellectual disability was significantly more frequent in TSC2 sporadic cases than in TSC1 sporadic cases (P=.0145). These data provide the first representative picture of the distribution and spectrum of mutations across the TSC1 and TSC2 loci in clinically ascertained TSC and support a difference in severity of TSC1- and TSC2-associated disease.
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Affiliation(s)
- A C Jones
- Institute of Medical Genetics, University of Wales College of Medicine, Cardiff CF4 4XN, United Kingdom
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12
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van Slegtenhorst M, Verhoef S, Tempelaars A, Bakker L, Wang Q, Wessels M, Bakker R, Nellist M, Lindhout D, Halley D, van den Ouweland A. Mutational spectrum of the TSC1 gene in a cohort of 225 tuberous sclerosis complex patients: no evidence for genotype-phenotype correlation. J Med Genet 1999; 36:285-9. [PMID: 10227394 PMCID: PMC1734341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Tuberous sclerosis complex is an inherited tumour suppressor syndrome, caused by a mutation in either the TSC1 or TSC2 gene. The disease is characterised by a broad phenotypic spectrum that can include seizures, mental retardation, renal dysfunction, and dermatological abnormalities. The TSC1 gene was recently identified and has 23 exons, spanning 45 kb of genomic DNA, and encoding an 8.6 kb mRNA. After screening all 21 coding exons in our collection of 225 unrelated patients, only 29 small mutations were detected, suggesting that TSC1 mutations are under-represented among TSC patients. Almost all TSC1 mutations were small changes leading to a truncated protein, except for a splice site mutation and two in frame deletions in exon 7 and exon 15. No clear difference was observed in the clinical phenotype of patients with an in frame deletion or a frameshift or nonsense mutation. We found the disease causing mutation in 13% of our unrelated set of TSC patients, with more than half of the mutations clustered in exons 15 and 17, and no obvious under-representation of mutations among sporadic cases. In conclusion, we find no support for a genotype-phenotype correlation for the group of TSC1 patients compared to the overall population of TSC patients.
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Affiliation(s)
- M van Slegtenhorst
- MGC Department of Clinical Genetics, Erasmus University, Rotterdam, The Netherlands
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13
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van Slegtenhorst M, Verhoef S, Tempelaars A, Bakker L, Wang Q, Wessels M, Bakker R, Nellist M, Lindhout D, Halley D, van den Ouweland A. Mutational spectrum of the TSC1 gene in a cohort of 225 tuberous sclerosis complex patients: no evidence for genotype-phenotype correlation. J Med Genet 1999. [DOI: 10.1136/jmg.36.4.285] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Tuberous sclerosis complex is an inherited tumour suppressor syndrome, caused by a mutation in either the TSC1 or TSC2 gene. The disease is characterised by a broad phenotypic spectrum that can include seizures, mental retardation, renal dysfunction, and dermatological abnormalities. The TSC1 gene was recently identified and has 23 exons, spanning 45 kb of genomic DNA, and encoding an 8.6 kb mRNA. After screening all 21 coding exons in our collection of 225 unrelated patients, only 29 small mutations were detected, suggesting that TSC1 mutations are under-represented among TSC patients. Almost all TSC1 mutations were small changes leading to a truncated protein, except for a splice site mutation and two in frame deletions in exon 7 and exon 15. No clear difference was observed in the clinical phenotype of patients with an in frame deletion or a frameshift or nonsense mutation. We found the disease causing mutation in 13% of our unrelated set of TSC patients, with more than half of the mutations clustered in exons 15 and 17, and no obvious under-representation of mutations among sporadic cases. In conclusion, we find no support for a genotype-phenotype correlation for the group of TSC1 patients compared to the overall population of TSC patients.
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14
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Kwiatkowska J, Wigowska-Sowinska J, Napierala D, Slomski R, Kwiatkowski DJ. Mosaicism in tuberous sclerosis as a potential cause of the failure of molecular diagnosis. N Engl J Med 1999; 340:703-7. [PMID: 10053179 DOI: 10.1056/nejm199903043400905] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- J Kwiatkowska
- Division of Experimental Medicine and Medical Oncology, Brigham and Women's Hospital, Boston, MA, USA
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15
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Johnson S. Rare diseases. 1. Lymphangioleiomyomatosis: clinical features, management and basic mechanisms. Thorax 1999; 54:254-64. [PMID: 10325903 PMCID: PMC1745441 DOI: 10.1136/thx.54.3.254] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- S Johnson
- Division of Respiratory Medicine, University of Nottingham, City Hospital, UK
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16
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Ali JB, Sepp T, Ward S, Green AJ, Yates JR. Mutations in the TSC1 gene account for a minority of patients with tuberous sclerosis. J Med Genet 1998; 35:969-72. [PMID: 9863590 PMCID: PMC1051505 DOI: 10.1136/jmg.35.12.969] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Tuberous sclerosis (TSC) is an autosomal dominant disorder characterised by tumour-like malformations (hamartomas) of the brain, skin, and other organs, often associated with seizures and learning disability. There is genetic heterogeneity with loci for TSC on chromosomes 9q34 (TSC1) and 16p13.3 (TSC2). The recently cloned TSC1 gene has 23 exons spanning some 40 kb of genomic DNA with an 8.6 kb transcript. We now report the results of mutation screening by SSCP and heteroduplex analysis of genomic DNA for all 21 coding exons of TSC1 in 83 unrelated cases of tuberous sclerosis. TSC1 gene mutations were found in 16 of the 83 cases (19%). These comprised base substitutions, small insertions, or small deletions giving rise to six nonsense mutations, eight frameshifts, and two splice site mutations, all of which would be expected to result in a truncated or absent protein. In the 10 cases predicted to have TSC1 mutations by linkage analysis or loss of heterozygosity studies, the mutation was identified in eight (80%). In the remaining 73 unassigned cases, only eight mutations were found (11%). From these data we estimate that TSC1 mutations accounted for 24% of the cases in this sample (and an estimated 22% of all TSC cases). This contrasts with data from linkage studies suggesting that TSC1 and TSC2 mutations account for approximately equal numbers of families.
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Affiliation(s)
- J B Ali
- Department of Pathology, University of Cambridge, Addenbrooke's Hospital, UK
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17
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Verhoef S, Vrtel R, Bakker L, Stolte-Dijkstra I, Nellist M, Begeer JH, Zaremba J, Jozwiak S, Tempelaars AM, Lindhout D, Halley DJ, van den Ouweland AM. Recurrent mutation 4882delTT in the GAP-related domain of the tuberous sclerosis TSC2 gene. Hum Mutat 1998; Suppl 1:S85-7. [PMID: 9452050 DOI: 10.1002/humu.1380110129] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- S Verhoef
- Department of Clinical Genetics, Erasmus University Hospital Rotterdam, The Netherlands
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18
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Au KS, Rodriguez JA, Finch JL, Volcik KA, Roach ES, Delgado MR, Rodriguez E, Northrup H. Germ-line mutational analysis of the TSC2 gene in 90 tuberous-sclerosis patients. Am J Hum Genet 1998; 62:286-94. [PMID: 9463313 PMCID: PMC1376882 DOI: 10.1086/301705] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Ninety patients with tuberous-sclerosis complex (TSC) were tested for subtle mutations in the TSC2 gene, by means of single-strand conformational analysis (SSCA) of genomic DNA. Patients included 56 sporadic cases and 34 familial probands. For all patients, SSCA was performed for each of the 41 exons of the TSC2 gene. We identified 32 SSCA changes, 22 disease-causing mutations, and 10 polymorphic variants. Interestingly, we detected mutations at a much higher frequency in the sporadic cases (32%) than in the multiplex families (9%). Among the eight families for which linkage to the TSC2 region had been determined, only one mutation was found. Mutations were distributed equally across the gene; they included 5 deletions, 3 insertions, 10 missense mutations, 2 nonsense mutations, and 2 tandem duplications. We did not detect an increase in mutations either in the GTPase-activating protein (GAP)-related domains of TSC2 or in the activating domains that have been identified in rat tuberin. We did not detect any mutations in the exons (25 and 31) that are spliced out in the isoforms. There was no evidence for correspondence between variability of phenotype and type of mutation (missense versus early termination). Diagnostic testing will be difficult because of the genetic heterogeneity of TSC (which has at least two causative genes: TSC1 and TSC2), the large size of the TSC2 gene, and the variety of mutations. More than half of the mutations that we identified (missense, small in-frame deletion, and tandem duplication) are not amenable to the mutation-detection methods, such as protein-truncation testing, that are commonly employed for genes that encode proteins with tumor-suppressor function.
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Affiliation(s)
- K S Au
- Department of Pediatrics, University of Texas Medical School, Houston, TX 77030, USA
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Wang Q, Verhoef S, Tempelaars AMP, Bakker PLG, Vrtel R, Hesseling-Janssen, ALW, Nellist M, Oranje AP, Stroink H, Lindhout D, Halley DJJ, van den Ouweland AMW. Identification of a large insertion and two novel point mutations (3671del8 and S1221X) in tuberous sclerosis complex (TSC) patients. Hum Mutat 1998. [DOI: 10.1002/(sici)1098-1004(1998)11:4<331::aid-humu14>3.0.co;2-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Maheshwar MM, Cheadle JP, Jones AC, Myring J, Fryer AE, Harris PC, Sampson JR. The GAP-related domain of tuberin, the product of the TSC2 gene, is a target for missense mutations in tuberous sclerosis. Hum Mol Genet 1997; 6:1991-6. [PMID: 9302281 DOI: 10.1093/hmg/6.11.1991] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Tuberous sclerosis is an autosomal dominant trait in which the dysregulation of cellular proliferation and differentiation results in the development of hamartomatous growths in many organs. The TSC2 gene is one of two genes determining tuberous sclerosis. Inactivating germline mutations of TSC2 in patients with tuberous sclerosis and somatic loss of heterozygosity at the TSC2 locus in the associated hamartomas indicate that TSC2 functions as a tumour suppressor gene and that loss of function is critical to expression of the tuberous sclerosis phenotype. The TSC2 product, tuberin, has a region of homology with the GTPase activating protein rap1GAP and stimulates the GTPase activity of rap1a and rab5a in vitro. Here we show that the region of homology between tuberin and human rap1GAP and the murine GAP mSpa1 is more extensive than previously reported and spans approximately 160 amino acid residues encoded within exons 34-38 of the TSC2 gene. Single strand conformation polymorphism analysis of these exons in 173 unrelated patients with tuberous sclerosis and direct sequencing of variant conformers together with study of additional family members enabled characterisation of disease associated mutations in 14 cases. Missense mutations, which occurred in exons 36, 37 and 38 were identified in eight cases, four of whom shared the same recurrent change P1675L. Each of the five different missense mutations identified was shown to occur de novo in at least one sporadic case of tuberous sclerosis. The high proportion of missense mutations detected in the region of the TSC2 gene encoding the GAP-related domain supports its key role in the regulation of cellular growth.
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Affiliation(s)
- M M Maheshwar
- Institute of Medical Genetics, University of Wales College of Medicine, Cardiff, UK
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van Slegtenhorst M, de Hoogt R, Hermans C, Nellist M, Janssen B, Verhoef S, Lindhout D, van den Ouweland A, Halley D, Young J, Burley M, Jeremiah S, Woodward K, Nahmias J, Fox M, Ekong R, Osborne J, Wolfe J, Povey S, Snell RG, Cheadle JP, Jones AC, Tachataki M, Ravine D, Sampson JR, Reeve MP, Richardson P, Wilmer F, Munro C, Hawkins TL, Sepp T, Ali JB, Ward S, Green AJ, Yates JR, Kwiatkowska J, Henske EP, Short MP, Haines JH, Jozwiak S, Kwiatkowski DJ. Identification of the tuberous sclerosis gene TSC1 on chromosome 9q34. Science 1997; 277:805-8. [PMID: 9242607 DOI: 10.1126/science.277.5327.805] [Citation(s) in RCA: 1103] [Impact Index Per Article: 40.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by the widespread development of distinctive tumors termed hamartomas. TSC-determining loci have been mapped to chromosomes 9q34 (TSC1) and 16p13 (TSC2). The TSC1 gene was identified from a 900-kilobase region containing at least 30 genes. The 8.6-kilobase TSC1 transcript is widely expressed and encodes a protein of 130 kilodaltons (hamartin) that has homology to a putative yeast protein of unknown function. Thirty-two distinct mutations were identified in TSC1, 30 of which were truncating, and a single mutation (2105delAAAG) was seen in six apparently unrelated patients. In one of these six, a somatic mutation in the wild-type allele was found in a TSC-associated renal carcinoma, which suggests that hamartin acts as a tumor suppressor.
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Affiliation(s)
- M van Slegtenhorst
- Department of Clinical Genetics, Erasmus University and University Hospital, Rotterdam, Netherlands
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Kobayashi T, Urakami S, Hirayama Y, Yamamoto T, Nishizawa M, Takahara T, Kubo Y, Hino O. Intragenic Tsc2 somatic mutations as Knudson's second hit in spontaneous and chemically induced renal carcinomas in the Eker rat model. Jpn J Cancer Res 1997; 88:254-61. [PMID: 9140109 PMCID: PMC5921374 DOI: 10.1111/j.1349-7006.1997.tb00375.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
We searched for the rat homologue of the human tuberous sclerosis (TSC2) gene mutations in loss of heterozygosity (LOH)-negative Eker rat renal carcinomas (RCs) by polymerase chain reaction-single-strand conformational polymorphism (PCR-SSCP) analysis using 45 primer sets covering all 41 coding exons and one leader exon including splicing donor/acceptor sites. We have identified intragenic somatic mutations in 7 of 21 spontaneous RCs, including one cell line (33%), and in 3 of 9 (33%) N-ethyl-N-nitrosourea (ENU)-induced LOH-negative RCs. Interestingly, five mutations in the spontaneous RCs were either deletion or duplication (5/7 = 71%). In contrast, all three in ENU-induced RCs were base substitutions (3/3 = 100%), as expected. Thus, a qualitative difference in the second hit might exist between spontaneous and ENU-induced mutations (e.g., deletion or duplication versus point mutation). By a direct cloning approach utilizing the restriction length difference caused by germline insertional mutation or reverse transcriptase-PCR analysis in two applicable cases, we could clearly show the presence of intragenic somatic mutations in the second copy (wild-type) of the Tsc2 gene. This is the first demonstration at the DNA sequence level of the validity of Knudson's two-hits hypothesis in the Tsc2 gene.
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Affiliation(s)
- T Kobayashi
- Department of Experimental Pathology, Cancer Institute, Tokyo
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