Low-level dystrophin expression attenuating the dystrophinopathy phenotype

Published:November 23, 2017DOI:


      • Nonsense dystrophin mutations do not always result in a severe phenotype.
      • Predicted nonsense mutations may instead affect exon splicing.
      • Very low-level dystrophin expression may be sufficient to significantly attenuate phenotype.


      The reading frame rule suggests that Duchenne muscular dystrophy (DMD) results from DMD mutations causing an out-of-frame transcript, whereas the milder Becker muscular dystrophy results from mutations causing an in-frame transcript. However, predicted nonsense mutations may instead result in altered splicing and an in-frame transcript. Here we report a 10-year-old boy with a predicted nonsense mutation in exon 42 who had a 6-minute walk time of 157% of that of age matched DMD controls, characterized as intermediate muscular dystrophy. RNA sequencing analysis from a muscle biopsy revealed only 6.0–9.8% of DMD transcripts were in-frame, excluding exon 42, and immunoblot demonstrated only 3.2% dystrophin protein expression. Another potential genetic modifier noted was homozygosity for the protective IAAM LTBP4 haplotype. This case suggests that very low levels of DMD exon skipping and dystrophin protein expression may result in amelioration of skeletal muscle weakness, a finding relevant to current dystrophin-restoring therapies.


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        • Flanigan K.M.
        Duchenne and Becker muscular dystrophies.
        Neurol Clin. 2014; 32 (viii): 671-688
        • Aartsma-Rus A.
        • Van Deutekom J.C.
        • Fokkema I.F.
        • Van Ommen G.J.
        • Den Dunnen J.T.
        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: 135-144
        • Monaco A.P.
        • Bertelson C.J.
        • Liechti-Gallati S.
        • Moser H.
        • Kunkel L.M.
        An explanation for the phenotypic differences between patients bearing partial deletions of the DMD locus.
        Genomics. 1988; 2: 90-95
        • Dent K.M.
        • Dunn D.M.
        • von Niederhausern A.C.
        • Aoyagi A.T.
        • Kerr L.
        • Bromberg M.B.
        • et al.
        Improved molecular diagnosis of dystrophinopathies in an unselected clinical cohort.
        Am J Med Genet A. 2005; 134: 295-298
        • Shiga N.
        • Takeshima Y.
        • Sakamoto H.
        • Inoue K.
        • Yokota Y.
        • Yokoyama M.
        • et al.
        Disruption of the splicing enhancer sequence within exon 27 of the dystrophin gene by a nonsense mutation induces partial skipping of the exon and is responsible for Becker muscular dystrophy.
        J Clin Invest. 1997; 100: 2204-2210
        • Tuffery-Giraud S.
        • Saquet C.
        • Thorel D.
        • Disset A.
        • Rivier F.
        • Malcolm S.
        • et al.
        Mutation spectrum leading to an attenuated phenotype in dystrophinopathies.
        Eur J Hum Genet. 2005; 13: 1254-1260
        • Flanigan K.M.
        • Dunn D.M.
        • von Niederhausern A.
        • Soltanzadeh P.
        • Howard M.T.
        • Sampson J.B.
        • et al.
        Nonsense mutation-associated Becker muscular dystrophy: interplay between exon definition and splicing regulatory elements within the DMD gene.
        Hum Mutat. 2011; 32: 299-308
        • Trabelsi M.
        • Beugnet C.
        • Deburgrave N.
        • Commere V.
        • Orhant L.
        • Leturcq F.
        • et al.
        When a mid-intronic variation of DMD gene creates an ESE site.
        Neuromuscul Disord. 2014; 24: 1111-1117
        • Banihani R.
        • Baskin B.
        • Halliday W.
        • Kobayashi J.
        • Kawamura A.
        • McAdam L.
        • et al.
        A novel mutation in DMD (c.10797+5G>A) causes Becker muscular dystrophy associated with intellectual disability.
        J Dev Behav Pediatr. 2016; 37: 239-244
        • Ginjaar I.B.
        • Kneppers A.L.
        • v d Meulen J.D.
        • Anderson L.V.
        • Bremmer-Bout M.
        • van Deutekom J.C.
        • et al.
        Dystrophin nonsense mutation induces different levels of exon 29 skipping and leads to variable phenotypes within one BMD family.
        Eur J Hum Genet. 2000; 8: 793-796
        • Melis M.A.
        • Muntoni F.
        • Cau M.
        • Loi D.
        • Puddu A.
        • Boccone L.
        • et al.
        Novel nonsense mutation (C→A nt 10512) in exon 72 of dystrophin gene leading to exon skipping in a patient with a mild dystrophinopathy.
        Hum Mutat. 1998; : S137-S138
        • Bouge A.L.
        • Murauer E.
        • Beyne E.
        • Miro J.
        • Varilh J.
        • Taulan M.
        • et al.
        Targeted RNA-Seq profiling of splicing pattern in the DMD gene: exons are mostly constitutively spliced in human skeletal muscle.
        Sci Rep. 2017; 7: 39094
        • Goemans N.
        • Klingels K.
        • van den Hauwe M.
        • Boons S.
        • Verstraete L.
        • Peeters C.
        • et al.
        Six-minute walk test: reference values and prediction equation in healthy boys aged 5 to 12 years.
        PLoS ONE. 2013; 8 (e84120)
        • Goemans N.
        • van den Hauwe M.
        • Wilson R.
        • van Impe A.
        • Klingels K.
        • Buyse G.
        Ambulatory capacity and disease progression as measured by the 6-minute-walk-distance in Duchenne muscular dystrophy subjects on daily corticosteroids.
        Neuromuscul Disord. 2013; 23: 618-623
        • Flanigan K.M.
        • Ceco E.
        • Lamar K.M.
        • Kaminoh Y.
        • Dunn D.M.
        • Mendell J.R.
        • et al.
        LTBP4 genotype predicts age of ambulatory loss in Duchenne muscular dystrophy.
        Ann Neurol. 2013; 73: 481-488
        • Flanigan K.M.
        • Dunn D.M.
        • von Niederhausern A.
        • Soltanzadeh P.
        • Gappmaier E.
        • Howard M.T.
        • et al.
        Mutational spectrum of DMD mutations in dystrophinopathy patients: application of modern diagnostic techniques to a large cohort.
        Hum Mutat. 2009; 30: 1657-1666
        • Disset A.
        • Bourgeois C.F.
        • Benmalek N.
        • Claustres M.
        • Stevenin J.
        • Tuffery-Giraud S.
        An exon skipping-associated nonsense mutation in the dystrophin gene uncovers a complex interplay between multiple antagonistic splicing elements.
        Hum Mol Genet. 2006; 15: 999-1013
        • Flanigan K.M.
        • Dunn D.
        • Larsen C.A.
        • Medne L.
        • Bonnemann C.B.
        • Weiss R.B.
        Becker muscular dystrophy due to an inversion of exons 23 and 24 of the DMD gene.
        Muscle Nerve. 2011; 44: 822-825
        • Martone J.
        • Briganti F.
        • Legnini I.
        • Morlando M.
        • Picillo E.
        • Sthandier O.
        • et al.
        The lack of the Celf2a splicing factor converts a Duchenne genotype into a Becker phenotype.
        Nat Commun. 2016; 7: 10488
        • Tuffery-Giraud S.
        • Chambert S.
        • Demaille J.
        • Claustres M.
        Point mutations in the dystrophin gene: evidence for frequent use of cryptic splice sites as a result of splicing defects.
        Hum Mutat. 1999; 14: 359-368
        • Juan-Mateu J.
        • Gonzalez-Quereda L.
        • Rodriguez M.J.
        • Verdura E.
        • Lazaro K.
        • Jou C.
        • et al.
        Interplay between DMD point mutations and splicing signals in Dystrophinopathy phenotypes.
        PLoS ONE. 2013; 8 (e59916)
        • Niba E.T.E.
        • Nishida A.
        • Tran V.K.
        • Vu D.C.
        • Matsumoto M.
        • Awano H.
        • et al.
        Cryptic splice activation but not exon skipping is observed in minigene assays of dystrophin c.9361+1G>A mutation identified by NGS.
        J Hum Genet. 2017; 62: 531-537
        • Deburgrave N.
        • Daoud F.
        • Llense S.
        • Barbot J.C.
        • Recan D.
        • Peccate C.
        • et al.
        Protein- and mRNA-based phenotype-genotype correlations in DMD/BMD with point mutations and molecular basis for BMD with nonsense and frameshift mutations in the DMD gene.
        Hum Mutat. 2007; 28: 183-195
        • Bello L.
        • Kesari A.
        • Gordish-Dressman H.
        • Cnaan A.
        • Morgenroth L.P.
        • Punetha J.
        • et al.
        Genetic modifiers of ambulation in the Cooperative International Neuromuscular Research Group Duchenne Natural History Study.
        Ann Neurol. 2015; 77: 684-696
        • van den Bergen J.C.
        • Hiller M.
        • Bohringer S.
        • Vijfhuizen L.
        • Ginjaar H.B.
        • Chaouch A.
        • et al.
        Validation of genetic modifiers for Duchenne muscular dystrophy: a multicentre study assessing SPP1 and LTBP4 variants.
        J Neurol Neurosurg Psychiatry. 2015; 86: 1060-1065
        • Mendell J.R.
        • Rodino-Klapac L.R.
        • Sahenk Z.
        • Roush K.
        • Bird L.
        • Lowes L.P.
        • et al.
        Eteplirsen for the treatment of Duchenne muscular dystrophy.
        Ann Neurol. 2013; 74: 637-647
        • Finkel R.S.
        • Flanigan K.M.
        • Wong B.
        • Bonnemann C.
        • Sampson J.
        • Sweeney H.L.
        • et al.
        Phase 2a study of ataluren-mediated dystrophin production in patients with nonsense mutation Duchenne muscular dystrophy.
        PLoS ONE. 2013; 8 (e81302)
        • Bushby K.
        • Finkel R.
        • Wong B.
        • Barohn R.
        • Campbell C.
        • Comi G.P.
        • et al.
        Ataluren treatment of patients with nonsense mutation dystrophinopathy.
        Muscle Nerve. 2014; 50: 477-487