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Li Q, Chen Z, Xiong H, Li R, Yu C, Meng J, Shi P, Kong X. Novel Partial Exon 51 Deletion in the Duchenne Muscular Dystrophy Gene Identified via Whole Exome Sequencing and Long-Read Whole-Genome Sequencing. Front Genet 2021; 12:762987. [PMID: 34899847 PMCID: PMC8662377 DOI: 10.3389/fgene.2021.762987] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 10/28/2021] [Indexed: 01/07/2023] Open
Abstract
Duchenne muscular dystrophy (DMD), one of the most common progressive and severely disabling neuromuscular diseases in children, can be largely attributed to the loss of function of the DMD gene on chromosome Xp21.2-p21.1. This paper describes the case of a 10-year-old boy diagnosed with DMD. Whole exome sequencing confirmed the hypothesized large partial exonic deletion of c.7310-11543_7359del (chrX:g.31792260_31803852del) spanning exon 51 and intron 50 in DMD. This large deletion was verified to be de novo by PCR, and the two breakpoints were further confirmed by Sanger sequencing and long-read whole-genome sequencing. Notably, this partial exonic deletion was the only complex variation in the deep intron regions or intron–exon junction regions in DMD. In addition, the case study demonstrates the clinical importance of using multiple molecular genetic testing methods for the diagnosis of rare diseases.
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Affiliation(s)
- Qianqian Li
- Genetics and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Zhanni Chen
- Genokon Institute of Medical Science and Laboratory, Xiamen, China
| | - Hui Xiong
- Genokon Institute of Medical Science and Laboratory, Xiamen, China
| | - Ranran Li
- School of Life Science and Technology, Xinxiang Medical University, Xinxiang, China
| | - Chenguang Yu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, Cardio-X Center, College of Life Science and Technology and Center for Human Genome Research, Huazhong University of Science and Technology, Wuhan, China
| | - Jingjing Meng
- Genetics and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Panlai Shi
- Genetics and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Xiangdong Kong
- Genetics and Prenatal Diagnosis Center, Department of Obstetrics and Gynecology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China
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Lin J, Li H, Liao Z, Wang L, Zhang C. Comparison of Carrier and de novo Pathogenic Variants in a Chinese DMD/BMD Cohort. Front Neurol 2021; 12:714677. [PMID: 34421809 PMCID: PMC8375267 DOI: 10.3389/fneur.2021.714677] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 07/14/2021] [Indexed: 01/14/2023] Open
Abstract
Background: Duchenne and Becker muscular dystrophy (DMD/BMD) are X-linked recessively inherited neuromuscular disorders caused by deletions, duplications, or small mutations in the DMD gene. With advances in prenatal diagnosis decreasing the number of affected offspring from carrier mothers, the frequency of de novo variants could increase. Therefore, determining the differences between the carrier and de novo variants of the DMD gene, which are rarely explored, is important for trial planning and genetic diagnosis in the future. Methods: A total of 440 patients, 349 of whom had DMD and 91 had BMD, diagnosed in our department between 2012 and 2019, along with their respective mothers, were included in this study. Multiplex ligation-dependent probe amplification was used to detected deletions and duplications in patients and their mothers. Small mutations were detected using next-generation sequencing in the patients, followed by Sanger sequencing in the mothers. Results: Deletions, duplications, and small mutations were identified in 204, 46, and 99 of the 349 patients with DMD and in 50, 10, and 31 of the 91 patients with BMD, respectively. De novo deletions were more concentrated in hotspot regions than carrier deletions of DMD/BMD. No clear bias was observed in the variant distribution between carriers, de novo duplications, and small mutations in DMD/BMD. The carrier frequency of DMD (61.6%) was lower than that of BMD (69.2%), but the difference was not statistically significant. The carrier frequency of deletions of the DMD gene (51.2%) was significantly lower than those of duplications (75%) and small mutations (81.5%). Conclusion: Compared to de novo deletions, deletions from carrier mothers had a wider distribution. Moreover, there was no significant difference between the carrier frequencies of DMD and BMD. Duplications and small mutations were more commonly inherited, while deletions were present de novo.
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Affiliation(s)
- Jinfu Lin
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, Guangzhou, China
| | - Huan Li
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, Guangzhou, China
| | - Ziyu Liao
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, Guangzhou, China
| | - Liang Wang
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, Guangzhou, China
| | - Cheng Zhang
- Department of Neurology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department and Key Discipline of Neurology, Guangzhou, China
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Wonkam‐Tingang E, Nguefack S, Esterhuizen AI, Chelo D, Wonkam A. DMD-related muscular dystrophy in Cameroon: Clinical and genetic profiles. Mol Genet Genomic Med 2020; 8:e1362. [PMID: 32543101 PMCID: PMC7434738 DOI: 10.1002/mgg3.1362] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 05/20/2020] [Accepted: 05/26/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Most of the previous studies on Duchenne Muscular Dystrophy (DMD) were conducted in Caucasian, Asian, and Arab populations. Therefore, little is known about the features of this disease in Africans. In this study, we aimed to determine the clinical characteristics of DMD, and the common mutations associated with this condition in a group of Cameroonian patients. METHODS We recruited DMD patients and performed a general physical examination on each of them. Multiplex ligand-dependant probe amplification was carried out to investigate exon deletions and duplications in the DMD gene (OMIM: 300377) of patients and their mothers. RESULTS A total of 17 male patients from 14 families were recruited, aged 14 ± 5.1 (8-23) years. The mean age at onset of symptoms was 4.6 ± 1.5 years, and the mean age at diagnosis was 12.1 ± 5.2 years. Proximal muscle weakness was noted in all patients and calf hypertrophy in the large majority of them (88.2%; 15/17). Flexion contractures were particularly frequent on the ankle (85.7%; 12/14). Wasting of shoulder girdle and thigh muscles was present in 50% (6/12) and 46.2% (6/13) of patients, respectively. No patient presented with hearing impairment. Deletions in DMD gene (OMIM: 300377) occurred in 45.5% of patients (5/11), while duplications were observed in 27.3% (3/11). Both mutation types were clustered between exons 45 and 50, and the proportion of de novo mutation was estimated at 18.2% (2/11). CONCLUSION Despite the first symptoms of DMD occurring in infancy, the diagnosis is frequently made later in adolescence, indicating an underestimation of the number of cases of DMD in Cameroon. Future screening of deletions and duplications in patients from Cameroon should focus on the distal part of the gene.
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Affiliation(s)
- Edmond Wonkam‐Tingang
- Division of Human GeneticsDepartment of PathologyUniversity of Cape TownCape TownSouth Africa
| | - Séraphin Nguefack
- Department of PaediatricsFaculty of Medicine and Biomedical SciencesUniversity of Yaoundé IYaoundéCameroon
- Paediatrics UnitDivision of Paediatric NeurologyGynaeco‐Obstetric and Paediatric HospitalYaoundéCameroon
| | - Alina I. Esterhuizen
- Division of Human GeneticsDepartment of PathologyUniversity of Cape TownCape TownSouth Africa
- National Health Laboratory ServiceGroote Schuur HospitalCape TownSouth Africa
| | - David Chelo
- Department of PaediatricsFaculty of Medicine and Biomedical SciencesUniversity of Yaoundé IYaoundéCameroon
- Division of Paediatric Cardiology, Mother and Child HospitalYaoundéCameroon
| | - Ambroise Wonkam
- Division of Human GeneticsDepartment of PathologyUniversity of Cape TownCape TownSouth Africa
- Department of MedicineUniversity of Cape TownCape TownSouth Africa
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4
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Vishnu V, Kumar M. Newer advances in the treatment of Duchenne muscular dystrophy and spinal muscular atrophy. JOURNAL OF CURRENT RESEARCH IN SCIENTIFIC MEDICINE 2019. [DOI: 10.4103/jcrsm.jcrsm_44_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Abstract
Duchenne muscular dystrophy (DMD) is a progressive X-linked degenerative muscle disease due to mutations in the DMD gene. Genetic confirmation has become standard in recent years. Improvements in the standard of care for DMD have led to improved survival. Novel treatments for DMD have focused on reducing the dystrophic mechanism of the muscle disease, modulating utrophin protein expression, and restoring dystrophin protein expression. Among the strategies to reduce the dystrophic mechanisms are 1) inhibiting inflammation, 2) promoting muscle growth and regeneration, 3) reducing fibrosis, and 4) facilitating mitochondrial function. The agents under investigation include a novel steroid, myostatin inhibitors, idebenone, an anti-CTGF antibody, a histone deacetylase inhibitor, and cardiosphere-derived cells. For utrophin modulation, AAV-mediated gene therapy with GALGT2 is currently being investigated to upregulate utrophin expression. Finally, the strategies for dystrophin protein restoration include 1) nonsense readthrough, 2) synthetic antisense oligonucleotides for exon skipping, and 3) AAV-mediated micro/minidystrophin gene delivery. With newer agents, we are witnessing the use of more advanced biotechnological methods. Although these potential breakthroughs provide significant promise, they may also raise new questions regarding treatment effect and safety.
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Affiliation(s)
- Perry B Shieh
- Department of Neurology, University of California, Los Angeles, 300 Medical Plaza, Suite B-200, Los Angeles, CA, 90095, USA.
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Garcia S, de Haro T, Zafra-Ceres M, Poyatos A, Gomez-Capilla JA, Gomez-Llorente C. Identification of de novo mutations of Duchénnè/Becker muscular dystrophies in southern Spain. Int J Med Sci 2014; 11:988-93. [PMID: 25076844 PMCID: PMC4115237 DOI: 10.7150/ijms.8391] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 06/12/2014] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Duchénnè/Becker muscular dystrophies (DMD/BMD) are X-linked diseases, which are caused by a de novo gene mutation in one-third of affected males. The study objectives were to determine the incidence of DMD/BMD in Andalusia (Spain) and to establish the percentage of affected males in whom a de novo gene mutation was responsible. METHODS Multiplex ligation-dependent probe amplification (MLPA) technology was applied to determine the incidence of DMD/BMD in 84 males with suspicion of the disease and 106 female relatives. RESULTS Dystrophin gene exon deletion (89.5%) or duplication (10.5%) was detected in 38 of the 84 males by MLPA technology; de novo mutations account for 4 (16.7%) of the 24 mother-son pairs studied. CONCLUSIONS MLPA technology is adequate for the molecular diagnosis of DMD/BMD and establishes whether the mother carries the molecular alteration responsible for the disease, a highly relevant issue for genetic counseling.
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Affiliation(s)
- Susana Garcia
- 1. UGC Laboratorios Clínicos. Hospital Universitario San Cecilio. Avd/Doctor Olóriz s/n 18012 Granada, Spain
| | - Tomás de Haro
- 1. UGC Laboratorios Clínicos. Hospital Universitario San Cecilio. Avd/Doctor Olóriz s/n 18012 Granada, Spain
- 2. Instituto de Investigación Biosanitaria ibs. Granada, Spain
| | - Mercedes Zafra-Ceres
- 1. UGC Laboratorios Clínicos. Hospital Universitario San Cecilio. Avd/Doctor Olóriz s/n 18012 Granada, Spain
| | - Antonio Poyatos
- 1. UGC Laboratorios Clínicos. Hospital Universitario San Cecilio. Avd/Doctor Olóriz s/n 18012 Granada, Spain
| | - Jose A. Gomez-Capilla
- 1. UGC Laboratorios Clínicos. Hospital Universitario San Cecilio. Avd/Doctor Olóriz s/n 18012 Granada, Spain
- 2. Instituto de Investigación Biosanitaria ibs. Granada, Spain
- 3. Departamento de Bioquímica y Biología Molecular III e Inmunología. Facultad de Medicina. Universidad de Granada. Avd/ Madrid s/n 18071, Granada, Spain
| | - Carolina Gomez-Llorente
- 4. Departamento de Bioquímica y Biología Molecular II. Instituto de Nutrición y Tecnología de los Alimentos “José Mataix”. Centro de Investigaciones Biomédicas. Universidad de Granada. Avd/ Conocimiento s/n 18100 Armilla, Granada, Spain
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Robinow M. Living history--autobiography: pediatric genetics in a New World. AMERICAN JOURNAL OF MEDICAL GENETICS 1995; 59:8-13. [PMID: 8849017 DOI: 10.1002/ajmg.1320590104] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- M Robinow
- Children's Medical Center, Dayton, Ohio, USA
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8
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Vosatka RJ, Brown G, Moffitt ST. Duchenne muscular dystrophy associated with fetal pleural effusion and polyhydramnios. Prenat Diagn 1993; 13:1139-41. [PMID: 8177833 DOI: 10.1002/pd.1970131209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
A case of fetal pleural effusion in a fetus affected with Duchenne muscular dystrophy (DMD) is reported. This case is discussed in the context of the previous observation of frequent stillbirths among male fetuses in DMD families.
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Affiliation(s)
- R J Vosatka
- Department of Pediatrics, College of Physicians and Surgeons of Columbia University, New York, NY 10032
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9
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van Essen AJ, Abbs S, Baiget M, Bakker E, Boileau C, van Broeckhoven C, Bushby K, Clarke A, Claustres M, Covone AE. Parental origin and germline mosaicism of deletions and duplications of the dystrophin gene: a European study. Hum Genet 1992; 88:249-57. [PMID: 1733826 DOI: 10.1007/bf00197255] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Knowledge about the parental origin of new mutations and the occurrence of germline mosaicism is important for estimating recurrence risks in Duchenne (DMD) and Becker muscular dystrophy (BMD). However, there are problems in resolving these issues partly because not all mutations can as yet be directly detected, and additionally because genetic ratios are very sensitive to ascertainment bias. In the present study, therefore, analysis was restricted to currently detectable mutations (deletions and duplications) in particular types of families which tend to be rare. In order to obtain sufficient data we pooled results from 25 European centers. In mothers of affected patients who were the first in their family with a dystrophin gene deletion or duplication, the ratio between the paternal and the maternal origin of this new mutation was 32:49 (binomial test P = 0.075) for DMD. In five BMD families the ratio between paternal and maternal origin of new mutations was 3:2. Recurrence risk because of maternal germline mosaicism was studied in sisters or subsequent sibs of isolated cases with an apparently new detectable mutation. In 12 out of 59 (0.20; 95% CI 0.10-0.31) transmissions of the risk haplotype the DMD mutation was transmitted as well. No recurrences were found in nine BMD families.
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Affiliation(s)
- A J van Essen
- Department of Medical Genetics, University of Groningen, The Netherlands
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10
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van Essen AJ, Busch HF, te Meerman GJ, ten Kate LP. Birth and population prevalence of Duchenne muscular dystrophy in The Netherlands. Hum Genet 1992; 88:258-66. [PMID: 1733827 DOI: 10.1007/bf00197256] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Mutations causing Duchenne muscular dystrophy (DMD) have a short survival. Therefore, birth and population prevalence are maintained by new mutations. The present inventory was made to estimate the birth and population prevalence rates of DMD in the Netherlands. Seven methods of case identification were used. Data on 496 definite, probable or possible DMD patients born since 1961, or alive on January 1, 1983, were obtained. Several methods gave an estimated ascertainment of more than 95%. The prevalence rate at birth of DMD was estimated at 23.7 x 10(-5) (1:4215) male live births (MLB) yearly. The prevalence rate in the male population on January 1, 1983 was 5.4 x 10(-5) (1:18496). About 1% of the males in this study may have autosomal recessive Duchenne-like muscular dystrophy. Until now there has been no convincing evidence for geographic differences in DMD prevalence at birth. A list of frequency studies of Duchenne muscular dystrophy is included. The DMD mutation rate calculated by the indirect method is 7.9 x 10(-5) genes per generation. However, this may well be an over-estimate, as this method does not account for germline mosaicism. Using a modified sex ratio method the proportion of sporadic DMD among all cases was estimated to be 0.106 (range 0-0.332). High frequency of germline mosaicism in DMD is a likely cause for the apparent lack of sporadic cases as found in previous studies, if mutation rates in male and female gametes are equal. Therefore, methods for estimating the proportion of new mutants in DMD should take germline mosaicism into account. The modified sex ratio method allows incorporation of data on germline mosaicism if available.
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Affiliation(s)
- A J van Essen
- Department of Medical Genetics, University of Groningen, The Netherlands
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11
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Rosendaal FR, Bröcker-Vriends AH, van Houwelingen JC, Smit C, Varekamp I, van Dijck H, Suurmeijer TP, Vandenbroucke JP, Briët E. Sex ratio of the mutation frequencies in haemophilia A: estimation and meta-analysis. Hum Genet 1990; 86:139-46. [PMID: 2148300 DOI: 10.1007/bf00197695] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A hereditary disease with excess mortality such as haemophilia is maintained in the population by the occurrence of new cases, i.e. mutations. In haemophilia, mutations may arise in female or male ancestors of a 'new' patient. The ratio of the mutation frequencies in males over females determines the prior risk of carriership of the mother of an isolated patient. An estimate of this prior risk is required for the application of Bayes' theorem to probability calculations in carriership testing. We have developed a method to estimate the sex ratio of the mutation frequencies; it does not depend on the assumption of genetic equilibrium, nor require an estimate of the reproductive fitness of haemophilia patients and carriers. Information from 462 patients with severe or moderately severe haemophilia A was gathered by postal questionnaires in a survey that included practically all Dutch haemophiliacs. Pedigree analysis was performed for the 189 patients of these 462, who were the first haemophiliacs in their family. By the maximum likelihood method, the ratio of the mutation frequencies in males and females was estimated at 2.1, with a 95% confidence interval of 0.7-6.7. In addition, we performed a meta-analysis of all published studies on the sex ratio of the mutation frequencies. When the results of six studies were pooled, it was estimated that mutations originated 3.1 times as often in males as in females. The 95% confidence interval was 1.9-4.9. This implies that 80% of mothers of an isolated patient are expected to be haemophilia carriers.
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Affiliation(s)
- F R Rosendaal
- Department of Clinical Epidemiology, University Hospital Leiden, The Netherlands
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Barbujani G, Russo A, Danieli GA, Spiegler AW, Borkowska J, Petrusewicz IH. Segregation analysis of 1885 DMD families: significant departure from the expected proportion of sporadic cases. Hum Genet 1990; 84:522-6. [PMID: 2338336 DOI: 10.1007/bf00210802] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The proportion of sporadic cases of Duchenne muscular dystrophy has been estimated by classical segregation analysis in a pooled sample of 1885 sibships from 7 different countries. A significant departure from the theoretical expectations based on mutation-selection equilibrium is observed (segregation frequency = 0.439 +/- 0.017; frequency of sporadic cases = 0.229 +/- 0.026, at the maximum likelihood). The occurrence of germinal mosaicism in some of the mothers of Duchenne cases may account for this peculiar finding, although a possible role of inequality of mutation rates in the two sexes cannot be ruled out.
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Affiliation(s)
- G Barbujani
- Dipartimento di Biologia, Università di Padova, Italy
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13
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Lane RJ, Partridge T, Rose FC. New mutations in Duchenne muscular dystrophy. Lancet 1988; 2:971-2. [PMID: 2902424 DOI: 10.1016/s0140-6736(88)92647-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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14
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Rivrud GN. Mutagenicity testing of seminal fluid: seminal fluid increases the mutagenicity of the precursor mutagen benzo[a]pyrene in the presence of S9 mix. Mutat Res 1988; 208:195-200. [PMID: 3041272 DOI: 10.1016/0165-7992(88)90060-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Small amounts of seminal fluid strongly enhanced the mutagenicity of the precursor mutagen benzo[a]pyrene (BP) in the Salmonella/microsome test. This previously unreported effect was found only in the presence of S9 mix for metabolic activation. The increase far exceeded the additive effect expected from experiments where seminal fluid and BP were tested separately with S9 mix. Testing of the direct-acting mutagen 4-nitro-o-phenylene-diamine (NPD) together with seminal fluid resulted in a lower mutagenic activity than that of NPD alone. Seminal fluid had a bactericidal effect on the Salmonella bacteria, thus only volumes up to 40 microliter could be used per plate. The mutagenic effect of only seminal fluid and S9 mix was slightly increased over controls in a standard Ames test, but was equal to the spontaneous mutation rate with a preincubation test modified according to Kado and coworkers. There were no significant differences between seminal plasma from smokers and non-smokers in any experimental series. Seminal fluid concentrated 20-fold by extraction with the mutagen-removing adsorbant Mutasorb did not have any enhancing effect on the mutagenicity of BP, nor did it exhibit any mutagenic activity in itself with or without S9 mix.
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Affiliation(s)
- G N Rivrud
- Department of Gynaecology and Obstetrics, National Hospital, University of Oslo, Norway
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15
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Grimm T, Danieli GA, Muller CR. Theoretical expectations for deletional mutations in Duchenne muscular dystrophy. AMERICAN JOURNAL OF MEDICAL GENETICS 1988; 29:445-51. [PMID: 3354618 DOI: 10.1002/ajmg.1320290230] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- T Grimm
- Department of Human Genetics, University of Wurzburg, Germany
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16
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Børresen AL, Heiberg A, Møller P, Berg K. Evidence for a sperm mutation resulting in Duchenne muscular dystrophy. Clin Genet 1987; 32:187-91. [PMID: 2887319 DOI: 10.1111/j.1399-0004.1987.tb03352.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
DNA analysis of Xp21 markers in a family with two brothers affected with Duchenne muscular dystrophy (DMD) revealed that the mutation most likely had occurred in a grandpaternal sperm. There is therefore a low risk that the maternal aunts and their daughters are carriers of the DMD gene.
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17
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Russo A, Barbujani G, Mostacciuolo ML, Herrmann FH, Spiegler AW, Galluzzi G, Danieli GA. Sporadic cases in Duchenne muscular dystrophy. A reappraisal through segregation analysis on 988 sibships. Hum Genet 1987; 76:230-5. [PMID: 3596597 DOI: 10.1007/bf00283613] [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: 01/06/2023]
Abstract
A new estimation of the proportion of sporadic cases in Duchenne muscular dystrophy was attempted by means of segregation analysis in a sample of 988 sibships collected on a world-wide scale by different authors. Maximum likelihood estimates of ascertainment probability (pi), segregation frequency (p), and frequency of sporadic cases (x) were calculated by Morton's equations under different hypotheses. The best fit was found for p = 0.454 +/- 0.024 and x = 0.235 +/- 0.034. The possibility that the proportion of sporadic cases might be lower than the expected 1/3 is suggested.
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18
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Gruemer HD, Prior T. Carrier detection in Duchenne muscular dystrophy: a review of current issues and approaches. Clin Chim Acta 1987; 162:1-18. [PMID: 2879654 DOI: 10.1016/0009-8981(87)90227-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The clinical chemistry laboratory has traditionally played a passive role in the application of technology to diagnostic interpretation. Recent developments offer the clinical laboratorian a renewed potential to enter the patient care arena as a consultant. Our lack of understanding of the disease processes in the muscular dystrophies places emphasis on prevention through carrier detection. This review summarizes the clinical progress of the disease, our present understanding of the genetics that control the mode of inheritance of the disease, and the analytical approaches to carrier detection, including their advantages and limitations. Recent advances allow the examination of the genetic material itself instead of concentrating on the phenotypic expression of biochemical abnormalities.
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19
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Edwards JH. The population genetics of Duchenne: natural and artificial selection in Duchenne muscular dystrophy. J Med Genet 1986; 23:521-30. [PMID: 3806638 PMCID: PMC1049833 DOI: 10.1136/jmg.23.6.521] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The dynamics of X linkage was derived by Haldane in 1935. It is clear that the majority of mutations to an X linked lethal are new and that methods of control based on relatives of known cases can have limited impact on future incidence. The ability to define and track neighbouring loci allows some carriers who are daughters of carriers to be detected, and possible carriers to be excluded, with high reliability. Fetal diagnosis may also be made in the same way, but not without a substantial casualty rate. The precision of such diagnosis by proxy is limited both by the estimate of the recombination fraction and its variance, and can rarely exceed 1/s where the recombinational data are based on s informative meioses. Bracketing loci provide greater security from failure to diagnose cases but may involve substantial casualty rates. The estimation of both failure rates and casualty rates is discussed.
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Karel ER, te Meerman GJ, Ten Kate LP. On the power to detect differences between male and female mutation rates for Duchenne muscular dystrophy, using classical segregation analysis and restriction fragment length polymorphisms. Am J Hum Genet 1986; 38:827-40. [PMID: 3014866 PMCID: PMC1684852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The power to detect departures from the theoretical proportion of new mutants in X-linked lethal disorders has been analyzed for several types of segregation analysis, including methods based on completely linked restriction fragment length polymorphisms. It is shown that all methods require large sample sizes in order to detect even large differences between male and female mutation rates. Ascertainment bias is shown to have a great effect on the outcome of the segregation analysis. All reviewed studies concerning the proportion of new mutants in Duchenne muscular dystrophy, whether they claimed equality or inequality between the male and female mutation rates, give insufficient evidence because of ascertainment bias and a too low power. An ascertainment bias-free method is given, with the advantage that information from many studies can be combined. By doing so, in the long run, even moderate departures from equality in mutation rates (if present) can be detected.
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Stern LM, Caudrey DJ, Clark MS, Perrett LV, Boldt DW. Carrier detection in Duchenne muscular dystrophy using computed tomography. Clin Genet 1985; 27:392-7. [PMID: 3995788 DOI: 10.1111/j.1399-0004.1985.tb02281.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
In Duchenne dystrophy computed tomography of muscles shows total or partial replacement of normal muscle by low density tissue, presumably representing fat. It was hypothesised that female carriers would have increased fat deposition, and hence lower density readings in certain muscle groups when compared with controls. Three C.T. scans, two through the thigh and one through the calf, were obtained on 9 obligate carriers, 12 "possible" carriers, and 10 controls. A total of 15 density readings in different muscle groups were obtained for each subject. The results, analysing the mean densities in Hounsfield units, show that the obligate carriers have statistically significant lower density readings than controls. The 9 obligate carriers and 10 controls were correctly allocated using discriminant function analysis of muscle density readings. An attempt to assign the "possible" carriers was made. The use of C.T. scanning in addition to creatine kinase (C. K.) estimations will significantly improve accuracy of genetic counselling and has the advantage of being non-invasive.
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Abstract
A segregation analysis on 135 Duchenne families from Venetia (Italy) suggests that the proportion of sporadic cases might be less than expected. Support for this view is also given by an analysis of a pooled sample including 284 additional sibships from comparable studies published previously. Several hypotheses were tested: the maximum likelihood was obtained for a segregation frequency p = 0.46 and for a proportion of sporadic cases x = 0.227 +/- 0.048.
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Abstract
Duchenne muscular dystrophy (DMD) is the most common sex linked lethal disease in man (one case in about 4000 male live births). The patients are wheelchair bound around the age of 8-10 years and usually die before the age of 20 years. The mutation rate, estimated by different methods and from different population studies, is in the order of 7 X 10(-5), which is higher than for any other X-linked genetic disease. Moreover, unlike other X linked diseases such as hemophilia A or Lesh-Nyhan's disease, there seems to be no sex difference for the mutation rates in DMD. Several observations of DMD in girls bearing X-autosomal translocations and linkage studies on two X chromosomal DNA restriction fragment length polymorphisms indicate that the DMD locus is situated on the short arm of the X chromosome, between Xp11 and Xp22. It may be of considerable length, and perhaps consisting of actively coding and non-active intervening DNA sequences. Thus unequal crossing over during meiosis in females could theoretically account for a considerable proportion of new mutations. However, there is no structurally or functionally abnormal protein known that might represent the primary gene product, nor has any pathogenetic mechanism leading to the observed biochemical and histological alterations been elucidated. Among the numerous pathogenetic concepts the hypothesis of a structural or/and functional defect of the muscular plasma membrane is still the most attractive. It would explain both the excess of muscular constituents found in serum of patients and carriers, such as creatine kinase (CK), as well as the excessive calcium uptake by dystrophic muscle fibres, which, prior to necrosis, could lead to hypercontraction, rupture of myofilaments in adjacent sarcomeres and by excessive Ca uptake to mitochondrial damage causing crucial energy loss. The results of studies on structural and functional membrane abnormalities in cells other than muscle tissue, e.g., erythrocytes, lymphocytes and cultured fibroblasts, indicate that the DMD mutation is probably demonstrable in these tissues. However, most of the findings are still difficult to reproduce or even controversial. DMD is an incurable disease; therefore most effort, in research as well as in practical medicine, is concentrated upon its prevention.(ABSTRACT TRUNCATED AT 400 WORDS)
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