A rare missense Duchenne muscular dystrophy gene variant in a family with muscular dystrophy from Turkey

Abstract

Objectives: Duchenne and Becker muscular dystrophies (DMD/BMD) are muscle diseases that show X-linked recessive inheritance. The disease occurs depending on large mutations, deletions/duplications, small mutations, point mutations and mid-intronic mutations of the gene encoding the protein called dystrophin. Therefore, in this study, we aimed to investigate the pathogenic variants of DMD in the affected family. 

Methods: A 23-year-old male who had weakness in the muscles, difficulty climbing the stairs, frequent falls at the age of seven was referred to the Medical Genetics department for an initial diagnosis of DMD/BMD. His siblings also suffered from similar symptoms. Therefore, eight individuals from the same family were included in the study. MLPA analysis was performed to evaluate deletion/duplication and variants of the DMD gene were evaluated by targeted NGS. Sophia DDM algorithms were used for the bioinformatics analysis of data, and the pathogenicity of the mutations was evaluated based on in silico prediction tools. 

Results: Allelic variants were identified in 8 individuals of the family including two suspected patients and six suspected obligatory carriers. NGS analysis revealed that proband and his nephew were hemizygous for pathogenic c.10018T> C (p.Cys3340Arg, C3340R) mutation and mother, two sisters and niece were carriers. 

Conclusions: C3340R mutation was first reported in a Taiwanese BMD patient among the 23 different pathologic changes. This variant identified as pathogenic because of being highly conserved cysteine substitution in the dystroglycan-binding domain of dystrophin. This study has the importance of reporting an infrequent pathogenic mutation, C3340R, in two patients and four suspected obligatory carriers of a Turkish family. 

Keywords

• Duchenne muscular dystrophy
• next-generation sequencing
• multiplex ligation-dependent probe amplification
• pathogenic

References

1. 1. Monaco AP, Bertelson CJ, Liechti-Gallati S, Moser H, Kunkel LM. An explanation for the phenotypic differences between patients bearing partial deletions of the DMD locus. Genomics 1988;2:90-5.
2. 2. Darras BT, Urion DK, Ghosh PS. In: Adam MP, Ardinger HH, Pagon RA, Wallace SE, Bean LJH, Stephens K, Amemiya A, eds. Dystrophinopathies.GeneReviews®. Seattle (WA): University of Washington, Seattle;2000: pp.1993-2018.
3. 3. Leiden Muscular Dystrophy pages. http://www.dmd.nl/. Accessed May 21, 2021.
4. 4. Monaco AP, Neve RL, Colletti-Feener C, Bertelson CJ, Kurnit DM, Kunkel LM. Isolation of candidate cDNAs for portions of the Duchenne muscular dystrophy gene. Nature 1986;323:646-50.
5. 5. Monaco AP, Bertelson CJ, Liechti-Gallati S, Moser H, Kunkel LM. An explanation for the phenotypic differences between patients bearing partial deletions of the DMD locus. Genomics 1988;2:90-5.
6. 6. Flanigan KM, Dunn DM, von Niederhausern A, Soltanzadeh P, Gappmaier E, Howard MT, et al. Mutational spectrum of DMD mutations in dystrophinopathy patients: application of modern diagnostic techniques to a large cohort. Hum Mutat 2009;30:1657-66.
7. 7. Gao QQ, McNally EM. The dystrophin complex: structure, function, and implications for therapy. Compr Physiol 2015;5:1223-39.
8. 8. Aartsma-Rus A, Van Deutekom JC, Fokkema IF, Van Ommen GJ, Den Dunnen JT. Entries in the Leiden Duchenne muscular dystrophy mutation database: an overview of mutation types and paradoxical cases that confirm the reading-frame rule. Muscle Nerve 2006;34:135-44.

9. 9. Prior TW, Papp AC, Snyder PJ, Burghes AH, Bartolo C, Sedra MS, Western LM, Mendell JR. A missense mutation in the dystrophin gene in a Duchenne muscular dystrophy patient. Nat Genet1993;4:357-60.
10. 10. The UMD-DMD Francedatabase. http://www.umd.be/DMD/W_DMD/index.html. Accessed May 21, 2021.
11. 11. Ma P, Zhang S, Zhang H, Fang S, Dong Y, Zhang Y, et al. Comprehensive genetic characteristics of dystrophinopathies in China. Orphanet J Rare Dis 2018;4;13:109.
12. 12. Juan-Mateu J, Gonzalez-Quereda L, Rodriguez MJ, Baena M, Verdura E, Nascimento A, et al. DMD mutations in 576 dystrophinopathy families: a step forward in genotype-phenotype correlations. PLoS One 2015;10:e0135189.
13. 13. Okubo M, Goto K, Komaki H, Nakamura H, Mori-Yoshimura M, Hayashi YK, et al. Comprehensive analysis for genetic diagnosis of Dystrophinopathies in Japan. Orphanet J Rare Dis 2017;12:149.
14. 14. Eraslan S, Kayserili H, Apak MY, Kirdar B. Identification of point mutations in Turkish DMD/BMD families using multiplex single stranded conformation analysis (SSCA). Eur J Hum Genet 1999;7:765-70.
15. 15. Hwa HL, Chang YY, Huang CH, Chen CH, Kao YS, Jong YJ, et al. Small mutations of the DMD gene in Taiwanese families. J Formos Med Assoc 2008;107:463-9.
16. 16. Wang Y, Yang Y, Liu J, Chen XC, Liu X, Wang CZ, et al. Whole dystrophin gene analysis by next-generation sequencing: a comprehensive genetic diagnosis of Duchenne and Becker muscular dystrophy. Mol Genet Genomics 2014;289:1013-21.
17. 17. Lenk U, Oexle K, Voit T, Ancker U, Hellner KA, Speer A, et al. A cysteine 3340 substitution inthe dystroglycan binding domain of dystrophin associated with Duchenne muscular dystrophy, mental retardation and absence of the ERG b-wave. Hum Mol Genet 1996;5:973-5.
18. 18. Bhattacharya S, Das A, Dasgupta R, Bagchi A. Analyses of the presence of mutations in Dystrophin protein to predict their relative influences in the onset of Duchenne Muscular Dystrophy. Cell Signal 2014;26:2857-64.
19. 19. Grimm T, Kress W, Meng G, Müller CR. Risk assessment and genetic counseling in families with Duchenne muscular dystrophy. Acta Myol 2012;31:179-83.
20. 20. Yang J, Li SY, Li YQ, Cao JQ, Feng SW, Wang YY, et al. MLPA-based genotype-phenotype analysis in 1053 Chinese patients with DMD/BMD. BMC Med Genet 2013;14:29.
21. 21. Ballo R, Viljoen D, Beighton P. Duchenne and Becker muscular dystrophy prevalence in South Africa and molecular findings in 128 persons affected. S Afr Med J 1994;84(8 Pt 1):494-7.
22. 22. Tehrani KHN, Hajiloo M, Asadollahi E, Lagini FP. Prevalence of muscular dystrophy in patients with muscular disorders in Tehran, Iran. Eur J Transl Myol 2018;28:7380.
23. 23. Haldane JB. The rate of spontaneous mutation of a human gene. 1935. J Genet 2004;83:235-44.
24. 24. Grimm T, Meng G, Liechti-Gallati S, Bettecken T, Müller CR, Müller B. On the origin of deletions and point mutations in Duchenne muscular dystrophy: most deletions arise in oogenesis and most point mutations result from events in spermatogenesis. J Med Genet 1994;31:183-6.
25. 25. Prior TW, Bridgeman SJ. Experience and strategy for the molecular testing of Duchenne muscular dystrophy. J Mol Diagn 2005;7:317-26.
26. 26. Hofstra RM, Mulder IM, Vossen R, de Koning-Gans PA, Kraak M, Ginjaar IB, et al. DGGE-based whole-gene mutation scanning of the dystrophin gene in Duchenne and Becker muscular dystrophy patients. Hum Mutat 2004;23:57-66.
27. 27. Aravind S, Ashley B, Mannan A, Ganapathy A, Ramesh K, Ramachandran A, et al. Targeted sequencing of the DMD locus: a comprehensive diagnostic tool for all mutations. Indian J Med Res 2019;150:282-9.
28. 28. Polavarapu K, Preethish-Kumar V, Sekar D, Vengalil S, Nashi S, Mahajan NP, et al. Mutation pattern in 606 Duchenne muscular dystrophy children with a comparison between familial and non-familial forms: a study in an Indian large single-center cohort. J Neurol 2019;266:2177-85.
29. 29. Okubo M, Minami N, Goto K, Goto Y, Noguchi S, Mitsuhashi S, et al. Genetic diagnosis of Duchenne/Becker muscular dystrophy using next-generation sequencing: validation analysis of DMD mutations. J Hum Genet 2016;61:483-9.
30. 30. Wang D, Gao M, Zhang K, Jin R, Lv Y, Liu Y, et al. Molecular genetics analysis of 70 Chinese families with muscular dystrophy using multiplex ligation-dependent probe amplification and next-generation sequencing. Front Pharmacol 2019;10:814.