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Wilton SD, Fall AM, Harding PL, McClorey G, Coleman C, Fletcher S. Antisense oligonucleotide-induced exon skipping across the human dystrophin gene transcript. Mol Ther 2007; 15:1288-96. [PMID: 17285139 DOI: 10.1038/sj.mt.6300095] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Protein-truncating mutations in the dystrophin gene lead to the most common childhood form of muscle wasting, Duchenne muscular dystrophy. Becker muscular dystrophy, a condition that typically arises from dystrophin gene lesions that do not disrupt the reading frame, clearly indicates that substantial domains of the dystrophin protein are not essential. Potential therapeutic intervention exists during pre-mRNA splicing, whereby selected exons are excised to either remove nonsense mutations or restore the reading frame around frame-shifting mutations from the mature mRNA. Appropriately designed antisense oligonucleotides (AOs), directed at amenable splicing motifs across the dystrophin gene transcript, block exon recognition and/or spliceosome assembly so that targeted exons are removed from the mature mRNA. We describe a panel of AOs designed to induce skipping of every exon within the human dystrophin gene transcript, with the exception of the first and last exons. Every exon targeted in vitro could be removed from the dystrophin mRNA, although some exons are more efficiently excluded than others. No single motif has emerged as a universal AO annealing site for redirection of dystrophin pre-mRNA processing, although the general trend is that the most efficient compounds are directed at motifs in the first half of the target exon.
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Affiliation(s)
- Steve D Wilton
- Experimental Molecular Medicine Group, Centre for Neuromuscular and Neurological Disorders, University of Western Australia, QE II Medical Centre, Nedlands, Western Australia, Australia.
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2
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Frisso G, Carsana A, Tinto N, Calcagno G, Salvatore F, Sacchetti L. Direct detection of exon deletions/duplications in female carriers of and male patients with Duchenne/Becker muscular dystrophy. Clin Chem 2004; 50:1435-8. [PMID: 15277355 DOI: 10.1373/clinchem.2004.033795] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Giulia Frisso
- Dipartimento di Biochimica e Biotecnologie Mediche and CEINGE Biotecnologie Avanzate, Università Federico II, Naples, Italy
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Watkins HC. Amplification of sequences from affected individuals. CURRENT PROTOCOLS IN HUMAN GENETICS 2001; Chapter 7:Unit 7.1. [PMID: 18428303 DOI: 10.1002/0471142905.hg0701s00] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
This unit describes methods for obtaining DNA sequences from an individual affected by a genetic disorder. Target sequences that may be present at very low copy number in patient samples are amplified by the polymerase chain reaction (PCR). The first Basic Protocol 1 describes harvesting of mRNA from peripheral lymphocytes, which can even be utilized for genes with tissue-specific patterns of expression. This technique has the advantage of ease of access to appropriate patient samples and also may provide a more efficient means of screening coding sequences than would analysis of individual exons. An alternate protocol describes modifications in PCR conditions that facilitate mutation analysis and sequencing. When the genomic sequence for a given candidate gene is known, the second Basic Protocol 2 may be used to obtain appropriate sequences for analysis of individual exons or noncoding regions of interest.
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Affiliation(s)
- H C Watkins
- Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA
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5
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van Essen AJ, Kneppers AL, van der Hout AH, Scheffer H, Ginjaar IB, ten Kate LP, van Ommen GJ, Buys CH, Bakker E. The clinical and molecular genetic approach to Duchenne and Becker muscular dystrophy: an updated protocol. J Med Genet 1997; 34:805-12. [PMID: 9350811 PMCID: PMC1051085 DOI: 10.1136/jmg.34.10.805] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Detection of large rearrangements in the dystrophin gene in Duchenne and Becker muscular dystrophy is possible in about 65-70% of patients by Southern blotting or multiplex PCR. Subsequently, carrier detection is possible by assessing the intensity of relevant bands, but preferably by a non-quantitative test method. Detection of microlesions in Duchenne and Becker muscular dystrophy is currently under way. Single strand conformational analysis, heteroduplex analysis, and the protein truncation test are mostly used for this purpose. In this paper we review the available methods for detection of large and small mutations in patients and in carriers and propose a systematic approach for genetic analysis and genetic counselling of DMD and BMD families, including prenatal and preimplantation diagnosis.
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Affiliation(s)
- A J van Essen
- Department of Medical Genetics, University of Groningen, The Netherlands
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6
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Yau SC, Bobrow M, Mathew CG, Abbs SJ. Accurate diagnosis of carriers of deletions and duplications in Duchenne/Becker muscular dystrophy by fluorescent dosage analysis. J Med Genet 1996; 33:550-8. [PMID: 8818939 PMCID: PMC1050661 DOI: 10.1136/jmg.33.7.550] [Citation(s) in RCA: 121] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We have developed a semiautomated approach to amplify 25 exons of the dystrophin gene using two fluorescent multiplex PCR assays which detect over 98% of reported deletions and 90% of duplications causing Duchenne/Becker muscular dystrophy. The 5' multiplex detects 11 exons from the proximal deletion hotspot of the gene while the 3' multiplex detects 14 exons from the central deletion hotspot. The PCR products are accurately sized and quantified by a fluorescent DNA sequencer after only 18 cycles of amplification. The amount of product amplified from each exon in a multiplex is divided by that from each of the other exons, and this ratio is compared with those from control samples to obtain a series of dosage quotients (DQ), from which the copy number of each exon is determined. No overlap was observed between the DQ values obtained from single and double copy loci. The assays can be used to screen both affected males and at risk female relatives for a mutation. The method has been evaluated as a female carrier test by conducting a blind trial on 150 coded samples. Sixty-three deletion carriers, two duplication carriers, and 84 normal female controls were all correctly identified, showing that carrier diagnosis is possible even in families where the nature of the mutation is unknown. Additionally the analysis showed a non-pathogenic duplication involving the muscle specific promoter and exon 1. Together these two multiplex assays detect over 70% of all mutations in the dystrophin gene, greatly simplifying and partly automating molecular diagnosis in Duchenne and Becker muscular dystrophy.
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Affiliation(s)
- S C Yau
- Division of Medical and Molecular Genetics, United Medical School, Guy's Hospital, London, UK
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7
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Affiliation(s)
- F L Mastaglia
- Australian Neuromuscular Research Institute, Queen Elizabeth II Medical Centre, Perth, Western Australia
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8
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9
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Meier-Heusler S, Pernin A, Liang H, Goumaz MO, Burger AG, Meier CA. Quantitation of beta 1 triiodothyronine receptor mRNA in human tissues by competitive reverse transcription polymerase chain reaction. J Endocrinol Invest 1995; 18:767-73. [PMID: 8787953 DOI: 10.1007/bf03349809] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Thyroid hormones act by binding to nuclear receptor proteins, the thyroid hormone receptors (TR) alpha and beta. Data from cell culture and animal studies indicate that TR expression may be regulated to modulate target organ responsiveness to thyroid hormone. To investigate whether such adaptive changes in TR expression occur in humans, we determined the mRNA levels of the hTR beta 1 in various thyroid states. Patients with overt hypo- or hyperthyroidism were enrolled in the study. Total RNA was isolated from peripheral blood mononuclear cells and hTR beta 1 mRNA levels determined by quantitative competitive reverse transcription PCR. For comparison, hTR beta 1 mRNA levels were determined in lymphocytes and normal thyroid tissue of euthyroid patients. Human TR beta 1 mRNA levels in lymphocytes were 1.8 +/- 0.4, 1.9 +/- 0.5, 1.1 +/- 0.4 10(-18) mol/microgram RNA in hypo-, eu- and hyperthyroid patients, respectively, corresponding to an estimated 0.5 - 2 molecules per cell. Although the mean hTR beta 1 mRNA levels were 40% lower in hyperthyroid than in euthyroid subjects, this difference did not reach statistical significance. Similar levels of hTR beta 1 mRNA levels were detected in thyroid gland from euthyroid patients. In summary, we developed an assay for the quantitative determination of hTR beta 1 mRNA levels in small human tissue samples, containing as little as 50 ng of total RNA. Absolute hTR beta 1 mRNA levels are very low with an estimated one molecule of mRNA being present in a mononuclear blood cell or thyrocyte. No up-regulation of hTR beta 1 was seen in hypothyroid relative to euthyroid patients. However, there is a non-significant trend towards a down-regulation of hTR beta 1 mRNA levels in hyperthyroid patients.
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10
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Morandi L, Bernasconi P, Gebbia M, Mora M, Crosti F, Mantegazza R, Cornelio F. Lack of mRNA and dystrophin expression in DMD patients three months after myoblast transfer. Neuromuscul Disord 1995; 5:291-5. [PMID: 7580241 DOI: 10.1016/0960-8966(94)00070-p] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We report our experience on myoblast transplantation in three Duchenne muscular dystrophy patients. Pure myoblasts (55 x 10(6) per patient) from HLA-matched donors, were injected into a tibialis anterior and the controlateral muscle was sham injected. Three months after transplantation, biopsies from the injected muscles were negative for dystrophin expression by immunocytochemistry. Reverse transcriptase-PCR (RT-PCR) failed to amplify any fragments of the deleted regions. This result confirms that myoblast transplantation is feasible, although the efficacy of this therapeutic approach is poor.
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Affiliation(s)
- L Morandi
- Department of Neuromuscular Diseases, Istituto Nazionale Neurologico C. Besta, Milan, Italy
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11
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Affiliation(s)
- R G Roberts
- Division of Medical and Molecular Genetics, United Medical and Dental Schools, London, United Kingdom
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12
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Lenk U, Hanke R, Speer A. Carrier detection in DMD families with point mutations, using PCR-SSCP and direct sequencing. Neuromuscul Disord 1994; 4:411-8. [PMID: 7881286 DOI: 10.1016/0960-8966(94)90080-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Non-isotopic single-strand conformation polymorphism (SSCP) and direct sequencing was used for carrier diagnosis in four families of DMD/BMD patients with previously characterized point mutations, leading to the identification of eight carriers and four non-carriers. When the mutation caused a distinctly altered migration pattern of the single strands, in principle, the SSCP-technique allowed determination of carrier status in the extended family of the probands without direct sequencing. However, because SSCP measures a function of not only the mutation, but of the entire sequence of the PCR product, it can lead to false negative and/or false positive diagnoses due to intronic and exonic sequence heterogeneity in the family. As we discovered this pitfall in one of the reported families, we concluded that for carrier testing the SSCP approach must be performed in essential conjunction with an independent assessment of the mutation site by direct sequencing.
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Affiliation(s)
- U Lenk
- Max-Delbrück-Centrum für Molekulare Medizin, Berlin-Buch, Germany
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13
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Antignac C, Knebelmann B, Drouot L, Gros F, Deschênes G, Hors-Cayla MC, Zhou J, Tryggvason K, Grünfeld JP, Broyer M. Deletions in the COL4A5 collagen gene in X-linked Alport syndrome. Characterization of the pathological transcripts in nonrenal cells and correlation with disease expression. J Clin Invest 1994; 93:1195-207. [PMID: 8132760 PMCID: PMC294071 DOI: 10.1172/jci117073] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The type IV collagen alpha 5 chain (COL4A5) gene of 88 unrelated male patients with X-linked Alport syndrome was tested for major gene rearrangements by Southern blot analysis, using COL4A5 cDNA probes. 14 different deletions were detected, providing a 16% deletion rate in the COL4A5 gene in the patient population. The deletions are dispersed all over the gene with different sizes, ranging from 1 kb to the complete absence of the gene (> 250 kb) in one patient. In four patients with intragenic deletions, absence of the alpha 3 (IV) chain in the glomerular basement membrane was demonstrated by immunohistochemical studies. This finding supports the hypothesis that abnormalities in the alpha 5 (IV) chain may prevent normal incorporation of the alpha 3 (IV) chain into the glomerular basement membrane. Direct sequencing of cDNA amplified from lymphoblast mRNA of four patients with internal gene deletions, using appropriate combinations of primers amplifying across the predicted boundaries of the deletions, allowed us to determine the effect of the genomic rearrangements on the transcripts and, by inference, on the alpha 5 (IV) chain. Regardless of the extent of deletion and of the putative protein product, the 14 deletions occur in patients with juvenile-type Alport syndrome.
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Affiliation(s)
- C Antignac
- INSERM U192, Hôpital Necker-Enfants Malades, Paris, France
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14
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Chan V, Au P, Lau P, Chan TK. A novel haemophilia B defect due to partial duplication of the factor IX gene. Br J Haematol 1994; 86:601-9. [PMID: 8043442 DOI: 10.1111/j.1365-2141.1994.tb04792.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A patient with mild FIX deficiency was found to have partial duplication of the 3' region of the gene, giving, in addition to the a normal gene, another piece of DNA containing exons 5', 6', 7' and 8' and the intervening sequences. Cloning and sequencing of the junction region revealed that crossover occurred at nt 31927 in the 3' untranslated region of one chromosome/chromatid and nt 10640 in intron 4 of the other. No homology or topoisomerase specific sequences were observed in the crossover region. PCR and sequencing of illegitimate FIX transcripts from the patient's lymphocytes showed at least three different species of mRNAs. Translation of two of these 'novel' mRNAs should result in truncated proteins. Possibilities for the splicing of the mature mRNA are offered to explain the translation of a normal-size FIX protein, which was the only product demonstrated on Western blot analysis.
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Affiliation(s)
- V Chan
- University Department of Medicine, Queen Mary Hospital, Hong Kong
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15
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Cooper DN, Berg LP, Kakkar VV, Reiss J. Ectopic (illegitimate) transcription: new possibilities for the analysis and diagnosis of human genetic disease. Ann Med 1994; 26:9-14. [PMID: 8166994 DOI: 10.3109/07853899409147321] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
By means of the Polymerase Chain Reaction (PCR), 'ectopic' or 'illegitimate' transcripts from any gene may be amplified from any tissue or cell type. RNA transcript analysis is therefore no longer dependent upon possession of the often inaccessible 'expressing' tissue. We review here the applications of ectopic transcript analysis to mutation detection and characterization, analysis of RNA splicing and the study of the genotype-phenotype relationship.
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Affiliation(s)
- D N Cooper
- Charter Molecular Genetics Laboratory, Thrombosis Research Institute, London, U.K
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16
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Muggleton-Harris AL. Inherited genetic defects: analysis and diagnosis at the cellular level in preimplantation embryos. INTERNATIONAL REVIEW OF CYTOLOGY 1994; 151:1-27. [PMID: 8014020 DOI: 10.1016/s0074-7696(08)62629-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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17
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Roberts RG, Gardner RJ, Bobrow M. Searching for the 1 in 2,400,000: a review of dystrophin gene point mutations. Hum Mutat 1994; 4:1-11. [PMID: 7951253 DOI: 10.1002/humu.1380040102] [Citation(s) in RCA: 105] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The past few years have seen a rapid increase in our knowledge of naturally occurring mutations in the dystrophin gene. Although earlier studies were limited to gross rearrangement mutations, we are now in a position to draw lessons on the molecular etiology of the remaining one-third of cases of Duchenne and Becker muscular dystrophy (DMD, BMD) which are associated with small mutations. This paper reviews 70 published and unpublished small mutations in the dystrophin gene and asks what we can learn about their nature, their distribution, and approaches to their characterisation. Strikingly for such a well-conserved gene, missense mutations are extremely rare, and the vast majority of DMD point mutations, like the gross rearrangements, result in premature translational termination. It seems increasingly likely that almost all cases of DMD arise solely as a result of a reduction in the level of dystrophin transcripts, and we argue that > 95% of DMD mutations contribute nothing to the functional dissection of the dystrophin protein. Most of the few BMD point mutations presented here are missense mutations in the N-terminal or C-terminal domains or are splice-site mutations that probably act, like BMD deletions, via the production of in-frame, interstitially deleted transcripts.
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Affiliation(s)
- R G Roberts
- Paediatric Research Unit, Guy's Hospital, London, England
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18
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Nishio H, Matsuo M, Kitoh Y, Narita N, Shimmoto M, Suzuki Y, Nakamura H. Brain- and muscle-type promoters of the dystrophin gene are selected in peripheral lymphocytes and Epstein Barr virus-transformed lymphoblastoid [correction of lymphoplastoid] cells. J Neurol 1993; 241:81-6. [PMID: 8138829 DOI: 10.1007/bf00869768] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Promoter-specific transcripts of the dystrophin gene in peripheral lymphocytes and Epstein Barr virus-transformed lymphoblastoid cells were analysed using reverse transcription-nested polymerase chain reaction. Two DNA fragments, corresponding to the alternative first exons transcribed from either brain- or muscle-type promoters, were both amplified from cDNA prepared from normal lymphocytes and lymphoblastoid cells. The nucleotide sequences of the amplified products were 100% homologous to the 5' termini of the cDNA of brain- and muscle-type dystrophins, respectively. Neither fragment was amplified from the lymphoblastoid cells of a patient with Duchenne muscular dystrophy, who has a partial deletion involving the brain- and muscle-type promoters in the dystrophin gene. These findings showed that the brain-type as well as the muscle-type promoter of the dystrophin gene was active in lymphocytes and lymphoblastoid cells.
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Affiliation(s)
- H Nishio
- Department of Pediatrics, Kobe University School of Medicine, Japan
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19
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Vainzof M, Passos-Bueno MR, Takata RI, Pavanello RDC, Zatz M. Intrafamilial variability in dystrophin abundance correlated with difference in the severity of the phenotype. J Neurol Sci 1993; 119:38-42. [PMID: 8246009 DOI: 10.1016/0022-510x(93)90189-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In Duchenne muscular dystrophy, the progression of the disease is always severe and predictable, while in Becker dystrophy there is a wide variability (intra and inter familial) in the severity of the phenotype. We report here a family in which the proband, who is currently 15 years old, is showing a severe DMD progression, while his affected maternal uncle, aged 29, has a more benign course, compatible with BMD. No DNA deletion was detected in both patients. Dystrophin analysis through immunofluorescence and western blotting showed a negative pattern in the youngest patient and a positive one in the oldest. Apparently, this is the first report on intrafamilial variability in dystrophin abundance correlated with a difference in the severity of the phenotype.
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Affiliation(s)
- M Vainzof
- Departamento de Biologia, Universidade de Sao Paulo, Brazil
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20
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Hiyama K, Kodaira M, Satoh C, Karakawa T, Kameo H, Yamakido M. Detection of partial deletion and partial duplication of dystrophin gene in Japanese patients with Duchenne or Becker muscular dystrophy. THE JAPANESE JOURNAL OF HUMAN GENETICS 1993; 38:169-76. [PMID: 8358041 DOI: 10.1007/bf01883707] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The dystrophin gene was analyzed in 59 Japanese patients with Duchenne muscular dystrophy (DMD) from 48 unrelated families, including 11 pairs of siblings, and three patients with Becker muscular dystrophy (BMD) from two unrelated families, including one pair of siblings. The relationship between the type of gene abnormality and clinical symptoms was examined. Twenty-seven of 50 (54.0%) unrelated DMD or BMD patients were found to have partial deletions, and five (10%) appeared to have partial duplications in the dystrophin gene. Nine DMD patients, including three pairs of siblings, showed mental retardation, the existence of which was coincident in each pair of siblings, but deletion of an identical exon was not always related to mental retardation in unrelated patients.
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Affiliation(s)
- K Hiyama
- Department of Genetics, Radiation Effects Research Foundation, Hiroshima, Japan
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21
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Baranov VS, Gorbunova VN, Malysheva OV, Artemyeva OV, Kascheeva TK, Evgrafov OV, Polyakov AV, Lebedev VM, Kuznetzova TV, Shlykova SN. Dystrophin gene analysis and prenatal diagnosis of Duchenne muscular dystrophy in Russia. Prenat Diagn 1993; 13:323-33. [PMID: 8101987 DOI: 10.1002/pd.1970130503] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Of 126 families referred for counselling of Duchenne muscular dystrophy (DMD), DNA analysis has been suggested to 119 families with at least one affected child or with an affected close male relative of the woman at risk of being a DMD carrier. A large proportion (about 80 per cent) of the families were represented by sporadic cases (only one affected individual). By means of multiplex polymerase chain reactions with different sets of oligoprimers providing amplification of 10-11 different exons, altogether 49 dystrophin gene deletions were identified (41 per cent). Eighteen deletions clustered in the 5' 'hot spot' region of DMD cDNA and 36 in the distal half of the central rod domain around exons 43-53. An unusually high frequency (18 per cent) of deletions involving exons 17-19 was discovered. Large deletions extending through both 'hot spot' regions and thus occupying over 30-40 exons were recorded in five cases (10 per cent). Seventy-six of 94 families were found to be informative by RFLP analysis for intragenic or extragenetic DNA probes. Carrier status was ascertained in 20 and rejected in 32 female relatives in 40 DMD families. Eight DMD-affected fetuses were diagnosed prenatally by direct deletion testing or by RFLP analysis. Feasible interpopulation variations in the dystrophin gene deletion pattern are discussed. The prospects for more effective prenatal diagnosis and carrier detection in high-risk DMD families in Russia are briefly outlined.
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Affiliation(s)
- V S Baranov
- Institute of Obstetrics and Gynaecology, Academy of Medical Sciences of Russia, St Petersburg
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22
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Narita N, Nishio H, Kitoh Y, Ishikawa Y, Ishikawa Y, Minami R, Nakamura H, Matsuo M. Insertion of a 5' truncated L1 element into the 3' end of exon 44 of the dystrophin gene resulted in skipping of the exon during splicing in a case of Duchenne muscular dystrophy. J Clin Invest 1993; 91:1862-7. [PMID: 8387534 PMCID: PMC288178 DOI: 10.1172/jci116402] [Citation(s) in RCA: 152] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
We report here the second evidence of retrotransposition of L1, which was found inserted into the dystrophin gene of a patient, causing Duchenne muscular dystrophy (DMD). When the PCR was used to amplify a region of the dystrophin gene encompassing exon 44 from genomic DNA of two Japanese brothers with DMD, it was found to be approximately 600 bp larger than expected. Both the normal and the abnormally large products were amplified from the DNA of their mother. However, the maternal grandparents did not have the abnormal allele, and the mutation must therefore have occurred in the mother. Analysis of nucleotide sequence of the amplified product from a patient disclosed that the insertion was present zero to two bases upstream from the 3' end of exon 44 and that two to four bases of the exon sequence were deleted from the insertion site. The insertion sequence was found to be composed of 606-608 bp and to be almost identical to the inverse complement of 3' portion of the L1 retrotransposon consensus sequence. The dystrophin gene transcript from peripheral lymphocytes of one of the patients was analyzed by using reverse transcription/semi-nested PCR. The size of the amplified product encompassing exon 42 to 46 was smaller than expected. Sequencing of the amplified product disclosed that the sequence of exon 43 was directly joined to that of exon 45. Exon 44 of the transcript was thus shown to be skipped during splicing. This novel mutation of the dystrophin gene has important implications regarding retrotransposition of an active L1 element and provides a new insight into the origins of mutations in the dystrophin gene.
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Affiliation(s)
- N Narita
- Department of Pediatrics, Kobe University School of Medicine, Japan
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23
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Gökgöz N, Kuseyri F, Topaloğlu H, Yüksel-Apak M, Kirdar B. Screening of deletions and RFLP analysis in Turkish DMD/BMD families by PCR. Clin Genet 1993; 43:261-6. [PMID: 8104108 DOI: 10.1111/j.1399-0004.1993.tb03814.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We have screened 76 DMD and 5 BMD patients for deletions, using two separate Multiplex gene amplification systems. The use of both systems together revealed deletions in 52% of the cases in the Turkish population. The majority of these deletions (33/37) were found to be localized within the central region of the dystrophin gene. The remaining deletions were mapped to the proximal hotspot. Deletion end-points were identified by PCR and/or by Southern blot analysis with cDNA probes, and exceptions to the Open Reading Frame (ORF) hypothesis are discussed. PCR-based techniques to screen the pERT87.15/XmnI, pERT87.15/BamHI, and pERT87.8/TaqI polymorphisms were used for linkage analysis in the Turkish DMD/BMD families, and approximately 70% of the mothers at risk were found to be informative for at least one of these polymorphisms studied.
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Affiliation(s)
- N Gökgöz
- Boğaziçi University, School of Arts and Sciences, Department of Biology, Bebek-Istanbul, Turkey
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24
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Lenk U, Demuth S, Kräft U, Hanke R, Speer A. Alternative splicing of dystrophin mRNA complicates carrier determination: report of a DMD family. J Med Genet 1993; 30:206-9. [PMID: 8474106 PMCID: PMC1016300 DOI: 10.1136/jmg.30.3.206] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Carrier determination is important for genetic counselling in DMD/BMD families. The detection of altered PCR amplified dystrophin mRNA fragments owing to deletions, insertions, or point mutations has increased the possibilities of carrier determination. However, problems may occur because of alternative splicing events. Here we present a family with a DMD patient characterised by a deletion of exons 45 to 54. At the mRNA level we detected a corresponding altered fragment which served for carrier determination. The mother and the sister of the patient showed the same altered dystrophin mRNA fragment as the patient and are therefore carriers. In the mother two additional altered dystrophin mRNA fragments were detectable, obviously resulting from alternative splicing in the normal allele. The grandmother and two other related females of the patient possess only the normal mRNA fragment. In a further female we detected an altered fragment owing to an mRNA deletion of exon 44. This fragment is created either by alternative splicing or a new mutation. Therefore, the carrier status of this female is still ambiguous indicating problems in carrier determination by the method of dystrophin mRNA analysis.
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Affiliation(s)
- U Lenk
- Max Delbrück Centre for Molecular Medicine, Berlin-Buch, Germany
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25
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Baranov VS. Molecular diagnosis of some common genetic diseases in Russia and the former USSR: present and future. J Med Genet 1993; 30:141-6. [PMID: 8445619 PMCID: PMC1016272 DOI: 10.1136/jmg.30.2.141] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The current state of molecular diagnosis of some common genetic diseases, including cystic fibrosis, Duchenne muscular dystrophy, haemophilia A and B, phenylketonuria, and thalassaemia, in Russia and elsewhere in the former USSR is reviewed. Data on carrier detection and prenatal diagnosis are presented and some objective problems and obstacles hampering efficient molecular diagnosis in Russia are discussed. The necessity for molecular diagnosis of some other inherited diseases (for example, von Willebrand's disease, Martin-Bell syndrome, polycystic kidney disease, Huntington's disease, and myotonic dystrophy) is stressed. The need for establishing new diagnostic centres dealing with the most common diseases, as well as rare genetic diseases, is substantiated. Perspectives on the implementation of new molecular methods and new technical approaches (preimplantation embryo diagnosis, fetal cells selected from maternal blood) are briefly outlined.
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Affiliation(s)
- V S Baranov
- Institute of Obstetrics and Gynecology, Academy of Medical Sciences of Russia, St Petersburg
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26
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Abstract
In about one-third of patients with Duchenne/Becker muscular dystrophy, the causative mutation does not involve gross alterations in the structure of the dystrophin gene. Prenatal diagnosis and carrier detection for such families is therefore dependent on the indirect method of linkage analysis with polymorphic DNA markers, a method that is subject to error. The identification of point mutations in the dystrophin gene in six affected males enabled us to develop direct assays, based on the polymerase chain reaction, that are specific for each of the mutations. In all six cases, the assays allowed us to offer families accurate carrier testing and prenatal diagnosis.
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Affiliation(s)
- S C Yau
- Paediatric Research Unit, United Medical School, Guy's Hospital, London, UK
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27
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Roberts RG, Bentley DR, Bobrow M. Infidelity in the structure of ectopic transcripts: a novel exon in lymphocyte dystrophin transcripts. Hum Mutat 1993; 2:293-9. [PMID: 8401537 DOI: 10.1002/humu.1380020409] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Ectopic (or "illegitimate") transcripts have recently become popular as a means of facilitating the study of transcripts normally considered to have a pattern of expression restricted to one or a few tissues. It has been generally assumed that the structure of an ectopic transcript faithfully represents that of its tissue-specific counterpart. We describe here the inclusion of a novel exon in 50% of ectopic dystrophin transcripts from human peripheral blood lymphocytes. The novel sequence resembles a conserved region in the 3' untranslated region of members of the carcinoembryonic antigen gene family and lies within the first intron of the human dystrophin gene. This constitutes a significant departure from the expected in vivo splicing behaviour in an ectopic transcript and suggests that there may be exceptions to the assumption that ectopic transcripts are processed in a similar way to their tissue-specific counterparts.
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Affiliation(s)
- R G Roberts
- Paediatric Research Unit, Guy's Hospital, London, England
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28
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Laing NG. Molecular genetics and genetic counselling for Duchenne/Becker muscular dystrophy. MOLECULAR AND CELL BIOLOGY OF HUMAN DISEASES SERIES 1993; 3:37-84. [PMID: 8111545 DOI: 10.1007/978-94-011-1528-5_3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- N G Laing
- Australian Neuromuscular Research Institute, QEII Medical Centre, Nedlands
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29
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Clarke AM, Mapstone NP, Quirke P. Molecular biology made easy. The polymerase chain reaction. THE HISTOCHEMICAL JOURNAL 1992; 24:913-26. [PMID: 1490867 DOI: 10.1007/bf01046497] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- A M Clarke
- Department of Clinical Medicine, University of Leeds, UK
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30
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Vainzof M, Passos-Bueno MR, Rapaport D, Pavanello RC, Zatz M, Bulman DE. Additional dystrophin fragment in Becker muscular dystrophy patients: correlation with the pattern of DNA deletion. AMERICAN JOURNAL OF MEDICAL GENETICS 1992; 44:382-4. [PMID: 1488991 DOI: 10.1002/ajmg.1320440323] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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31
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Affiliation(s)
- K M Bushby
- Department of Human Genetics, Newcastle upon Tyne
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32
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Rininsland F, Hahn A, Niemann-Seyde S, Slomski R, Hanefeld F, Reiss J. Identification of a new DMD gene deletion by ectopic transcript analysis. J Med Genet 1992; 29:647-51. [PMID: 1383546 PMCID: PMC1016097 DOI: 10.1136/jmg.29.9.647] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The detailed genetic analysis of the Duchenne/Becker muscular dystrophy gene is hindered by the large number of exons involved and their separation by huge introns. These problems can be overcome by the analysis of mRNA rather than genomic DNA and ectopic transcripts derived from peripheral blood lymphocytes provide a convenient source of material. Using reverse transcription and nested PCR, we show here a comprehensive strategy for the rapid and complete analysis of the coding sequences from complex genes and illustrate its potential by the identification of a hitherto undescribed single exon deletion.
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Affiliation(s)
- F Rininsland
- Institut für Humangenetik, Universitätskliniken, Göttingen, Germany
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33
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Fong Y, Moldawer LL, Lowry SF. Experimental and clinical applications of molecular cell biology in nutrition and metabolism. JPEN J Parenter Enteral Nutr 1992; 16:477-86. [PMID: 1433784 DOI: 10.1177/0148607192016005477] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Rapid advances in molecular biology have yielded important new techniques for understanding the cellular mechanisms of normal homeostasis and disease. In particular, molecular laboratory methodologies have become important investigative tools for nutritional studies. Detection techniques for specific DNAs, RNAs, and proteins allow direct examination of cellular regulation of protein expression in health and illness. Construction of transgeneic models by recent techniques of inserting foreign genes into experimental animals has provided novel models for studies of cellular metabolism. In addition, molecular biology has had impact on clinical nutrition and therapy. Molecular techniques not only allow for early diagnosis of many inborn genetic errors of metabolism, recombinant technology has also provided for large-scale production of proteins and hormones of potential therapeutic value. The possibility for direct gene therapies is also nearing reality. Hence, understanding the language of molecular biology and the recent developments in this field is not only of research interest, but is also of clinical relevance.
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Affiliation(s)
- Y Fong
- Department of Surgery, New York Hospital-Cornell Medical Center, New York 10021
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34
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Bies RD, Caskey CT, Fenwick R. An intact cysteine-rich domain is required for dystrophin function. J Clin Invest 1992; 90:666-72. [PMID: 1644931 PMCID: PMC443149 DOI: 10.1172/jci115909] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The carboxyl terminus of dystrophin is encoded by a highly conserved, alternatively spliced region of the gene. The few rare mutations reported in this region are of interest in unraveling the function of the dystrophin molecule. An unusual case of infantile onset Duchenne muscular dystrophy (DMD) with an internal 3' genomic deletion, and a membrane localized non-functional dystrophin protein, was used to explore the functional activity of this region. The patient's cDNA sequence showed an intragenic 1824-bp deletion precisely excising the cysteine rich and alternatively spliced COOH-terminal domains of dystrophin. The unaltered final 2.7 kb of the patients transcript was defined as a single exon localized to two genomic fragments, with the 5.9 kb HindIII fragment containing the stop codon. To understand the significance of deletions in this important region of the dystrophin gene, we mapped the order and cDNA coordinates for the 3' genomic HindIII fragments encoding the cysteine rich and alternative splicing domains. This 3' gene map was used to compare the clinical phenotype of the other reported COOH-terminal deletions in the literature. Our analysis concludes that the cysteine-rich domain confers an important function for the dystrophin protein.
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Affiliation(s)
- R D Bies
- Division of Cardiology, Baylor College of Medicine, Houston, Texas 77030
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35
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Glass IA, Nicholson LV, Watkiss E, Johnson MA, Roberts RG, Abbs S, Brittain-Jones S, Boddie HG. Investigation of a female manifesting Becker muscular dystrophy. J Med Genet 1992; 29:578-82. [PMID: 1518025 PMCID: PMC1016067 DOI: 10.1136/jmg.29.8.578] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Females manifesting Becker muscular dystrophy (BMD) are even more rarely observed than for the allelic condition Duchenne muscular dystrophy. The male proband has typical BMD with greatly raised CK activity and a myopathic muscle biopsy. His mother experienced walking difficulties from 35 years of age and has a myopathy with marked calf hypertrophy, a raised CK, and a myopathic muscle biopsy. Dystrophin analysis was undertaken on both the proband and his mother. Immunoblotting showed a protein of normal size but of reduced abundance in both. Immunocytochemical analysis in the proband indicated that the majority of the fibres showed weak dystrophin labelling and in his mother both dystrophin positive and dystrophin negative fibres were present. Non-random X inactivation at locus DXS255, was observed in DNA isolated from peripheral lymphocytes of the mother. Neither extended multiplex PCR performed on DNA from the proband nor analysis of lymphocyte derived mRNA showed a structural alteration in the dystrophin gene suggesting that an unusual mutation was responsible for BMD in this family.
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Affiliation(s)
- I A Glass
- West Midlands Regional Genetics Service, Birmingham Maternity Hospital
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36
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Lau YL, Srivastava G, Wong V, Liu YT, Ho FC, Yeung CY. Deletions, duplications and novel restriction fragment length polymorphism in Duchenne and Becker muscular dystrophies. Clin Genet 1992; 41:252-8. [PMID: 1351430 DOI: 10.1111/j.1399-0004.1992.tb03676.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
To determine the mutations of Southern Chinese with Duchenne and Becker muscular dystrophies (DMD, BMD), we analysed 28 DMD and BMD patients in 24 unrelated families for intragenic deletions and duplications by using cDNA probes covering the entire 14 kb of the dystrophin gene. Deletions were detected in nine unrelated patients (seven patients by probe 8 and two by probe 2b-3). Gene duplications were detected by probe 1-2a in two patients with the duplication bands confirmed in both Hind III and Bgl II digests and by densitometry. A third patient was found to have a junction fragment with Bgl II and a duplication band with Hind III by probe 5b-7. Therefore 50% of the 24 unrelated families were found to have either deletions or duplications. A previously undescribed restriction fragment length polymorphism (RFLP) was found in one family with probe 5b-7 in Bgl II digests which was found to segregate with the disease phenotype. This new RFLP was not detected in over 70 unrelated X chromosomes we have examined so far, and appeared to be "private" for this family. The presence of this new restriction site may or may not be the mutation responsible for the disease phenotype.
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Affiliation(s)
- Y L Lau
- Department of Paediatrics, University of Hong Kong
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37
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Adinolfi M, Stone S, Moralli D. Carrier detection of deletions in female relatives of X-linked disorders by non-isotopic in situ hybridisation. Bioessays 1992; 14:421-6. [PMID: 1503558 DOI: 10.1002/bies.950140614] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Recent studies suggest that a non-isotopic in situ hybridisation (NISH) approach can be successfully employed to investigate the carrier status of female relatives in families of selected patients with Duchenne muscular dystrophy (DMD) or Hunter syndrome, whose diseases are due to a specific X chromosome deletion. Whilst the majority of metaphase spreads from normal females show specific hybridisation signals on both X chromosomes when tested with either dystrophin or Hunter gene-derived probes, only one X chromosome in each metaphase spread will show the relevant hybridisation complex in female carriers of deletions involving the dystrophin or Hunter gene. Thus, the NISH method can be a valuable diagnostic tool for the detection of the carrier status of female relatives of patients with X chromosome deletions.
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Affiliation(s)
- M Adinolfi
- Paediatric Research Unit, United Medical School, Guy's Hospital, London, UK
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38
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Gussoni E, Pavlath GK, Lanctot AM, Sharma KR, Miller RG, Steinman L, Blau HM. Normal dystrophin transcripts detected in Duchenne muscular dystrophy patients after myoblast transplantation. Nature 1992; 356:435-8. [PMID: 1557125 DOI: 10.1038/356435a0] [Citation(s) in RCA: 343] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Gene delivery by transplantation of normal myoblasts has been proposed as a treatment of the primary defect, lack of the muscle protein dystrophin, that causes Duchenne muscular dystrophy (DMD), a lethal human muscle degenerative disorder. To test this possibility, we transplanted normal myoblasts from a father or an unaffected sibling into the muscle of eight boys with DMD, and assessed their production of dystrophin. Three patients with deletions in the dystrophin gene expressed normal dystrophin transcripts in muscle biopsy specimens taken from the transplant site one month after myoblast injection. Using the polymerase chain reaction we established that the dystrophin in these biopsies derived from donor myoblast DNA. These results show that transplanted myoblasts persist and produce dystrophin in muscle fibres of DMD patients.
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Affiliation(s)
- E Gussoni
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, California 94305
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39
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Abstract
Defining the range of mutations in genes that cause human disease is essential to determine the mechanisms of genetic variation and the function of gene domains and to perform precise carrier and prenatal diagnosis. The mutations in one-third of Duchenne muscular dystrophy patients remain unknown as they do not involve gross rearrangements of the dystrophin gene. The size and complexity of the gene have prohibited the systematic definition of point mutations. We have developed a method for the identification of these mutations by nested amplification, chemical mismatch detection, and sequencing of reverse transcripts of trace amounts of dystrophin mRNA from peripheral blood lymphocytes. Analysis of the entire coding region (11 kilobases) in seven patients has resulted in detection of a sequence change in each case that is clearly sufficient to cause the disease. All mutations should cause premature translational termination, and the resulting phenotypes are thus equivalent to those caused by frameshifting deletions. The results support a particular functional importance for the C-terminal region of dystrophin. Application of this approach to mutation detection will extend direct carrier and prenatal diagnosis to virtually every affected family.
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Affiliation(s)
- R G Roberts
- Paediatric Research Unit, United Medical School, Guy's Campus, London, United Kingdom
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40
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Fonknechten N, Chelly J, Lepercq J, Kahn A, Kaplan JC, Kitzis A, Chomel JC. CFTR illegitimate transcription in lymphoid cells: quantification and applications to the investigation of pathological transcripts. Hum Genet 1992; 88:508-12. [PMID: 1372586 DOI: 10.1007/bf00219336] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Since the isolation of the cystic fibrosis transmembrane conductance regulator gene (CFTR) and the characterization of the main mutation (delta F508) in 1989, a large number of rare mutations has been found. Full screening of the CFTR gene is difficult because it is split into 27 exons covering 250 kb of genomic DNA. This gene is essentially expressed in the lung and intestinal tract, neither of which are easily accessible for routine investigations. The recent description of a faint transcription of highly tissue-specific genes in any cell, a phenomenon known as illegitimate transcription, would facilitate the research of mutations and the characterization of truncated m-RNA caused by splicing mutations. Using the polymerase chain reaction on cDNA (cDNA-PCR), we detected transcripts of the CFTR gene in lymphocytes and lymphoblast cells at a very low level (about 300 times less than in lung or intestine). This strategy allowed us to obtain a sufficient amount of cDNA-PCR product compatible with further molecular analyses. We have, therefore, analyzed a cDNA fragment overlapping exons 10 and 11 by polyacrylamide gel electrophoresis and direct sequencing, and detected the delta F508 mutation at this level. Our protocol can be generalized to the investigation of the total 4.5-kb CFTR coding sequence.
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41
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42
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Abstract
Efficient methods for the detection of mutations are of fundamental importance in research and in diagnostics. By detection of a DNA sequence alteration that cosegregates with a clinical phenotype in an affected family, the gene at fault may be identified and assigned a function. Mutation detection methods are also a rate-limiting factor for the clinical application of DNA diagnostics. Currently a large number of techniques are in use to scan for new mutations and to distinguish among previously established sequence variants. Here, some of the problems connected with mutation detection are discussed together with principles on which current and future mutation detection assays can be based.
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Affiliation(s)
- U Landegren
- Department of Medical Genetics, Uppsala Biomedical Center, Sweden
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43
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Kaplan JC, Kahn A, Chelly J. Illegitimate transcription: its use in the study of inherited disease. Hum Mutat 1992; 1:357-60. [PMID: 1301944 DOI: 10.1002/humu.1380010502] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
In 1988, by using the powerful and accurate cDNA/PCR technique, it was demonstrated that there are very low levels of dystrophin mRNA in a variety of non-muscle tissues, including cultured fibroblasts and lymphoblastoid cell lines. The phenomenon was also shown for a number of other tissue-specific genes, including beta-globin, factors VIIIc and IX, anti-Müllerian hormone, L-pyruvate kinase, retinal blue pigment, phenylalanine hydroxylase. The level of transcript in inappropriate cells is exceedingly low, perhaps one mRNA per 100-1000 cells. This low-level ubiquitous transcription of tissue-specific genes was called "illegitimate" or "ectopic" transcription, and has been proven to occur for 17 gene transcripts to date. The mechanism and biological significance of illegitimate transcription are still obscure, but, since illegitimate transcripts exhibit the same pathology as legitimate transcripts, they have been useful tool in the study of already 9 inherited diseases. This strategy will be applied widely for diseases where samples from the appropriate tissue for study is difficult to obtain, or where an mRNA is easier or more informative to study than a genomic DNA (as for large genes, or where alternative splicing is involved).
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Affiliation(s)
- J C Kaplan
- INSERM U129, Institut Cochin de Génétique Moléculaire, Paris, France
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44
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Rosenzweig A, Watkins H, Hwang DS, Miri M, McKenna W, Traill TA, Seidman JG, Seidman CE. Preclinical diagnosis of familial hypertrophic cardiomyopathy by genetic analysis of blood lymphocytes. N Engl J Med 1991; 325:1753-60. [PMID: 1944483 DOI: 10.1056/nejm199112193252501] [Citation(s) in RCA: 141] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND The clinical diagnosis of familial hypertrophic cardiomyopathy is usually made on the basis of the physical examination, electrocardiogram, and echocardiogram. Making an accurate diagnosis can be particularly difficult in children, who may not have cardiac hypertrophy until adulthood. Recently, we demonstrated that mutations in the cardiac myosin heavy-chain genes cause familial hypertrophic cardiomyopathy in some families. We report a diagnostic test for familial hypertrophic cardiomyopathy that relies on the detection of mutations in the beta myosin heavy-chain gene in circulating lymphocytes that we used to evaluate three generations of a family, including the children. METHODS AND RESULTS Using the polymerase chain reaction, we found that normal and mutant beta cardiac myosin heavy-chain genes are transcribed in circulating lymphocytes. This allowed us to examine beta cardiac myosin heavy-chain messenger RNA from blood lymphocytes, even though ordinary expression of the gene is virtually restricted to the heart. Base sequences amplified from this messenger RNA were analyzed with a ribonuclease protection assay to identify small deletions, abnormal splicing, or missense mutations. Using this technique we identified a novel missense mutation in a patient with familial hypertrophic cardiomyopathy. We evaluated 15 of the patient's adult relatives and found perfect agreement with the clinical diagnosis (8 affected and 7 not affected). Clinical analysis of 14 of the children (age, 1 to 20 years) of these affected family members revealed 1 child with echocardiographic findings diagnostic of familial hypertrophic cardiomyopathy. However, genetic analyses showed that six other children had also inherited the missense mutation and might later manifest the disease. CONCLUSIONS Transcripts of beta cardiac myosin heavy-chain gene can be detected in blood lymphocytes and used to screen for mutations that cause familial hypertrophic cardiomyopathy. This approach makes practical the identification of mutations responsible for this disorder and may be applicable to other diseases in which direct analysis is difficult because the mutated gene is expressed only in certain tissues. Preclinical or prenatal screening in an affected family will make it possible to study the disease longitudinally and to develop preventive interventions.
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Affiliation(s)
- A Rosenzweig
- Cardiac Unit, Massachusetts General Hospital, Boston
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45
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Chalkley G, Harris A. Lymphocyte mRNA as a resource for detection of mutations and polymorphisms in the CF gene. J Med Genet 1991; 28:777-80. [PMID: 1770535 PMCID: PMC1017114 DOI: 10.1136/jmg.28.11.777] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- G Chalkley
- Division of Medical and Molecular Genetics, United Medical and Dental Schools of Guy's Hospital, London
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46
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Abstract
Evidence suggesting that dystrophin is a component of the membrane cytoskeleton of excitable cells continues to accumulate. Whereas the specific mechanisms leading to muscle pathology in Duchenne muscular dystrophy are still being debated it is apparent that the progressive weakness that occurs in this disease is the result of a chronic process that is initiated by dystrophin deficiency.
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Affiliation(s)
- C V Rojas
- Department of Molecular Genetics, University of Pittsburgh School of Medicine, Pennsylvania 15261
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47
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Chelly J, Gilgenkrantz H, Hugnot JP, Hamard G, Lambert M, Récan D, Akli S, Cometto M, Kahn A, Kaplan JC. Illegitimate transcription. Application to the analysis of truncated transcripts of the dystrophin gene in nonmuscle cultured cells from Duchenne and Becker patients. J Clin Invest 1991; 88:1161-6. [PMID: 1918370 PMCID: PMC295575 DOI: 10.1172/jci115417] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
We have previously demonstrated that there is a low level of transcription of tissue-specific genes in every cell type. In this study, we have taken advantage of this phenomenon, called illegitimate transcription, to analyze the muscle-type dystrophin mRNA in easily accessible cells such as lymphoid cells, fibroblasts, and peripheral blood cells from Duchenne and Becker muscular dystrophies with known internal gene deletion. The results showed that, in the studied regions surrounding the deletions, processing of truncated transcripts is identical in specific (muscle tissue) and in nonspecific cells (lymphoid cells). In Becker cases with out-of-frame deletions, the already described alternatively spliced species found in muscle samples were also found in nonspecific cells. These results demonstrate that illegitimate transcripts are a bona fide version of tissue-specific mRNA, and that they represent a useful material to investigate the qualitative consequences of gene defects at the mRNA level.
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Affiliation(s)
- J Chelly
- Unité 129, Institut National de la Santé et de la Recherche Médicale, Institut Cochin de Génétique Moléculaire, Paris, France
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48
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Abstract
In this brief review, we describe the clinical manifestations of Duchenne's muscular dystrophy (DMD) and other similar syndromes, outline the history of the dystrophin gene's identification and its relationship to these muscular dystrophies, and relate the importance of the gene's discovery to clinical neurology. We do not discuss treatment.
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Affiliation(s)
- B K Evans
- Department of Neurology, University of Alabama, Birmingham Medical School 35294
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49
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Abstract
Progress in understanding the role of dystrophin raises promising hopes for a treatment for Duchenne muscular dystrophy. In addition, great improvements have been made in the ability to diagnose this disease using simple molecular methods.
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Affiliation(s)
- J S Chamberlain
- Department of Human Genetics, University of Michigan Medical School, Ann Arbor 48190-0618
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50
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Arahata K. Dystrophin abnormality in progressive muscular dystrophy--a review article. ACTA PAEDIATRICA JAPONICA : OVERSEAS EDITION 1991; 33:216-21. [PMID: 1957648 DOI: 10.1111/j.1442-200x.1991.tb01546.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Duchenne muscular dystrophy (DMD) is a fatal X-linked recessive disorder of muscle in children, with an incidence of approximately 1 in 3,300 male births. In about a third of affected boys, the disease is due to a new mutation, and most patients die in their early 20s. Over the last few years, the genetic, biochemical and histopathological basis of DMD has been elucidated greatly. In particular, the discovery of "dystrophin," the protein product of the DMD gene is truly an epoch-making success in the history of muscular dystrophy research. Dystrophin is now thought to be a cytoskeletal protein underlying the plasma membrane (known in muscle as the sarcolemma) of normal muscle fiber, and is undetectable or greatly reduced in DMD. In this review article, dystrophin in normal skeletal muscle and various neuromuscular diseases including DMD/BMD (Becker muscular dystrophy), and its carrier is discussed.
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Affiliation(s)
- K Arahata
- Division of Neuromuscular Research, National Institute of Neuroscience, Tokyo, Japan
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