1
|
Elhawary NA, Jiffri EH, Jambi S, Mufti AH, Dannoun A, Kordi H, Khogeer A, Jiffri OH, Elhawary AN, Tayeb MT. Molecular characterization of exonic rearrangements and frame shifts in the dystrophin gene in Duchenne muscular dystrophy patients in a Saudi community. Hum Genomics 2018; 12:18. [PMID: 29631625 PMCID: PMC5891934 DOI: 10.1186/s40246-018-0152-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Accepted: 04/02/2018] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND In individuals with Duchenne muscular dystrophy (DMD), exon skipping treatment to restore a wild-type phenotype or correct the frame shift of the mRNA transcript of the dystrophin (DMD) gene are mutation-specific. To explore the molecular characterization of DMD rearrangements and predict the reading frame, we simultaneously screened all 79 DMD gene exons of 45 unrelated male DMD patients using a multiplex ligation-dependent probe amplification (MLPA) assay for deletion/duplication patterns. Multiplex PCR was used to confirm single deletions detected by the MLPA. RESULTS There was an obvious diagnostic delay, with an extremely statistically significant difference between the age at initial symptoms and the age of clinical evaluation of DMD cases (t value, 10.3; 95% confidence interval 5.95-8.80, P < 0.0001); the mean difference between the two groups was 7.4 years. Overall, we identified 147 intragenic rearrangements: 46.3% deletions and 53.7% duplications. Most of the deletions (92.5%) were between exons 44 and 56, with exon 50 being the most frequently involved (19.1%). Eight new rearrangements, including a mixed deletion/duplication and double duplications, were linked to seven cases with DMD. Of all the cases, 17.8% had duplications with no hot spots. In addition, confirmation of the reading frame hypothesis helped account for new DMD rearrangements in this study. We found that 81% of our Saudi patients would potentially benefit from exon skipping, of which 42.9% had a mutation amenable to skipping of exon 51. CONCLUSIONS Our study could generate considerable data on mutational rearrangements that may promote future experimental therapies in Saudi Arabia.
Collapse
Affiliation(s)
- Nasser A Elhawary
- Department of Medical Genetics, Medicine College, Umm Al-Qura University, P.O. Box 57543, Mecca, 21955, Saudi Arabia.
- Department of Molecular Genetics, Faculty of Medicine, Ain Shams University, Cairo, 11566, Egypt.
| | - Essam H Jiffri
- Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdul-Aziz University, Jeddah, Saudi Arabia
| | - Samira Jambi
- Department of Pediatrics, Al Hada Military Hospital, Al Hada, Saudi Arabia
| | - Ahmad H Mufti
- Department of Medical Genetics, Medicine College, Umm Al-Qura University, P.O. Box 57543, Mecca, 21955, Saudi Arabia
| | - Anas Dannoun
- Department of Medical Genetics, Medicine College, Umm Al-Qura University, P.O. Box 57543, Mecca, 21955, Saudi Arabia
| | - Hassan Kordi
- Department of Medical Genetics, Medicine College, Umm Al-Qura University, P.O. Box 57543, Mecca, 21955, Saudi Arabia
| | - Asim Khogeer
- Department of Plan and Research, General Directorate of Health Affairs, Mecca Region, Ministry of Health, Mecca, Saudi Arabia
| | - Osama H Jiffri
- Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdul-Aziz University, Jeddah, Saudi Arabia
| | | | - Mohammed T Tayeb
- Department of Medical Genetics, Medicine College, Umm Al-Qura University, P.O. Box 57543, Mecca, 21955, Saudi Arabia
| |
Collapse
|
2
|
Molecular characterization of exonic rearrangements and frame shifts in the dystrophin gene in Duchenne muscular dystrophy patients in a Saudi community. Hum Genomics 2018. [PMID: 29631625 DOI: 10.1186/s40246-018-0152-8]] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In individuals with Duchenne muscular dystrophy (DMD), exon skipping treatment to restore a wild-type phenotype or correct the frame shift of the mRNA transcript of the dystrophin (DMD) gene are mutation-specific. To explore the molecular characterization of DMD rearrangements and predict the reading frame, we simultaneously screened all 79 DMD gene exons of 45 unrelated male DMD patients using a multiplex ligation-dependent probe amplification (MLPA) assay for deletion/duplication patterns. Multiplex PCR was used to confirm single deletions detected by the MLPA. RESULTS There was an obvious diagnostic delay, with an extremely statistically significant difference between the age at initial symptoms and the age of clinical evaluation of DMD cases (t value, 10.3; 95% confidence interval 5.95-8.80, P < 0.0001); the mean difference between the two groups was 7.4 years. Overall, we identified 147 intragenic rearrangements: 46.3% deletions and 53.7% duplications. Most of the deletions (92.5%) were between exons 44 and 56, with exon 50 being the most frequently involved (19.1%). Eight new rearrangements, including a mixed deletion/duplication and double duplications, were linked to seven cases with DMD. Of all the cases, 17.8% had duplications with no hot spots. In addition, confirmation of the reading frame hypothesis helped account for new DMD rearrangements in this study. We found that 81% of our Saudi patients would potentially benefit from exon skipping, of which 42.9% had a mutation amenable to skipping of exon 51. CONCLUSIONS Our study could generate considerable data on mutational rearrangements that may promote future experimental therapies in Saudi Arabia.
Collapse
|
3
|
Abstract
The discovery of the subsarcolemmal muscle fiber protein dystrophin has, to a certain extent, replaced former nosological terms of Duchenne (DMD) and Becker (BMD) muscular dystrophies by the term dystrophinopathies. The immunohistochemical and Western blot analysis of dystrophin has not only enlarged the clinical spectrum of dystrophinopathies, but has also made carrier detection of DMD more reliable, particularly in manifesting carriers without family history. Moreover, prenatal muscle biopsy, under selected circumstances, can show presence or absence of dystrophin, ie, in the latter case an affected male fetus. Molecular genetics have provided a wealth of genetic details in the dystrophinopathies, but therapy has not yet succeeded to a similar extent, on the contrary, myoblast transplantation has not resulted in any clinical improvement.
Collapse
Affiliation(s)
- B Reitter
- Department of Pediatrics, Mainz University Medical Center, Germany
| | | |
Collapse
|