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Humu-2014-0536
Databases
The TREAT-NMD DMD Global database: Analysis of more than 7000 Duchenne
Muscular Dystrophy mutations
*Catherine L. Bladen1, *David Salgado2, Soledad Monges3, Maria E. Foncuberta3, Kyriaki
Kekou4, Konstantina Kosma4, Hugh Dawkins5, Leanne Lamont5, Anna J. Roy6, Teodora
Chamova7, Velina Guergueltcheva7, Sophelia Chan8, Lawrence Korngut9, Craig Campbell10,
Yi Dai11, Jen Wang12, Nina Barišić13, Petr Brabec14, Jaana Lahdetie15, Maggie C. Walter16,
Olivia Schreiber-Katz16, Veronika Karcagi17, Marta Garami17, Venkatarman Viswanathan18,
Farhad Bayat19, Filippo Buccella20, En Kimura21, Zaïda Koeks22, Janneke C. van den
Bergen22, Miriam Rodrigues23, Richard Roxburgh23, Anna Lusakowska24, Anna Kostera-
Pruszczyk24, Janusz Zimowski25, Rosário Santos26, Elena Neagu27, Svetlana Artemieva28,
Vedrana Milic Rasic29, Dina Vojinovic29, Manuel Posada30, Clemens Bloetzer31, Pierre-Yves
Jeannet31, Franziska Joncourt32, Jordi Díaz-Manera33, Eduard Gallardo33, A. Ayşe
Karaduman34, Haluk Topaloğlu35, Rasha El Sherif36, Angela Stringer37, Andriy V. Shatillo38,
Ann S. Martin39, Holly L. Peay39, Matthew I, Bellgard40, Jan Kirschner41, Kevin M.
Flanigan42, Volker Straub1, Kate Bushby1, Jan Verschuuren22, Annemieke Aartsma-Rus1,43,
Christophe Beroud2,44, Hanns Lochmüller1.
This article is protected by copyright. All rights reserved. 2
*Equal contribution
1The John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine,
Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK. 2Aix Marseille Université, Inserm,
GMGF UMR_S 910, 13385, Marseille, France. 3Hospital de Pediatría J. P. Garrahan,
Pichincha 1881, Argentina. 4Department of Medical Genetics, Medical School, University of
Athens, Choremio Research Laboratory,St. Sophia's Children's Hospital Thinon & Levadia
Goudi, Athens, 11527, Greece. 5Office of Population Health Genomics, Department of
Health, Perth, Western Australia, Australia. 6WIV-ISP, Juliette Wytsman 14, 1050 Brussels,
Belgium. 7Department of Neurology, Medical University-Sofia, 1 Georgi Sofiiski Str, Sofia,
Bulgaria. 8Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital, the
University of Hong Kong. 9Department of Clinical Neurosciences and Hotchkiss Brain
Institute, University of Calgary, Calgary, Canada; Address: Clinical Neurosciences, South
Health Campus, 4448 Front Street SE, Calgary, Alberta, Canada. 10Department of Paediatrics,
Clinical Neurological Sciences & Epidemiology, Western University, London, Ontario,
Canada. 11Department of Neurology, Peking Union Medical College Hospital, Peking Union
Medical College and Chinese Academy of Medical Sciences, Beijing, China. 12China Dolls,
Department of Neurology, the General Hospital of Chinese Armed Police Forces, 69
Yongding Road, Haidian District, Beijing 100039, P.R. China. 13Division of Paediatric
Neurology, University Hospital Centre Zagreb (KBC Zagreb), University of Zagreb Medical
School, Croatia. 14Institute for Biostatistic and Analyses, Masaryk University, Kamenice
126/3, 625 00 Brno, Czech Republic. 15Dept. Child Neurology, Turku University Central
Hospital, Turku, Finland. 16Friedrich-Baur-Institute, Department of Neurology, Ludwig-
Maximilians-University of Munich, Ziemssenstr. 1a, Munich, 80336, Germany. 17NIEH,
Dept. of Molecular Genetics and Diagnostics, Albert Florian str 2-6, Budapest, 1097,
Hungary. 18CHILDS Trust Medical Research Foundation and Apollo Children's Hospital,
Chennai, India. 19Pasteur Institute of Iran, Karaj complex, Tehran, Iran. 20Parent Project
Onlus, Via Nicola Coviello n.12, Roma, Italy. 214-1-1 Ogawa-Higashi, Kodaira,Tokyo 187-
8551, Japan. 22Leiden University Medical Center, Department of Neurology, Albinusdreef 2,
2333 ZA Leiden, The Netherlands. 23Department of Neurology, Auckland DHB, Private
Bag 92024, Auckland, New Zealand. 24Department of Neurology, Medical University of
Warsaw, Warsaw, Poland. 25Department of Genetics , Institute of Psychiatry and Neurology,
Warsaw, Poland. 26Centro de Genética Médica Jacinto Magalhães, Praça Pedro Nunes 88,
4099-028, Porto, Portugal. 27National Institute of Legal Medicine, Genetics Laboratory 9,
This article is protected by copyright. All rights reserved. 3
Vitan Barzesti, Bucharest, 042122. 28Moscow Institute of Pediatrics, 2, Taldomskaya str,
Moscow, Russia. 29Clinic for Neurology and Psychiatry for Children and Youth, Faculty of
Medicine, University of Belgrade, Dr Subotica 6A, 11000 Belgrade, Serbia. 30Institute of
Rare Diseases Research, SpainRDR and CIBERER, Institute of Health Carlos III, Madrid,
Spain. 31Neurorehabilitation Unit, Lausanne University Hospital, Lausanne, Switzerland.
32Division of Human Genetics, Children's University Hospital, Inselspital, Bern,
Switzerland.33Unitat de Malalties Neuromusculars, Servei de Neurologia, Hospital de la
Santa Creu i Sant Pau de Barcelona. 34Hacettepe University Faculty of Health Sciences
Department of Physiotherapy and Rehabilitation and and Hacettepe University Faculty of
Health Sciences Department of Physiotherapy and Rehabilitation 06100, Altındağ, Ankara,
Turkey. 35Hacettepe Children's Hospital 06100 Ankara, Turkey. 36Neurology& Neurogenic
Unit, Egypt Air Hospital, Ain Shams University, Egypt. 37Action Duchenne, Epicentre, 41
West Street, London E11 4LJ, UK. 38Institute of Neurology, Psychiatry and Narcology of
NAMS, Academic Pavlov st. 46, Kharkiv 61068, Ukraine. 39DuchenneConnect, 401
Hackensack Ave, 9th Floor, Hackensack, NJ 07601, USA. 40Centre for Comparative
Genomics, Murdoch University, Murdoch, Western Australia, 6150. 41University Medical
Center Freiburg, Germany. 42Center for Gene Therapy, The Research Institute, WA3014,
Nationwide Children‟s Hospital, 700 N. Children‟s Drive, Columbus, Ohio 43205. 43Leiden
University Medical Center, Department of Human Genetics, Leiden, The Netherlands.
44INSERM APHM, Hôpital d'Enfants de la Timone, Département de Génétique Médicale et
de Biologie Cellulaire, 13385, Marseille, France.
This article is protected by copyright. All rights reserved. 4
Corresponding Author:
Catherine L. Bladen
University of Newcastle
Institute if Genetic Medicine
Times Square
Newcastle upon Tyne
Newcastle
NE13BZ
United Kingdom
E-mail: catherine.bladen@ncl.ac.uk
Funding: This work was supported by TREAT-NMD operating grants, FP6 LSHM-CT-
2006-036825, 20123307 UNEW_FY2013 and AFM 16104. Further support came from the
European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement
No. 305444 (RD-Connect) and 305121 (Neuromics).
This article is protected by copyright. All rights reserved. 5
Abstract
Analysing the type and frequency of patient specific mutations that give rise to Duchenne
Muscular Dystrophy (DMD) is an invaluable tool for diagnostics, basic scientific research,
trial planning and improved clinical care. Locus specific databases (LSDBs) allow for the
collection, organization, storage and analysis of genetic variants of disease. Here we describe
the development and analysis of the TREAT-NMD DMD Global database
(http://umd.be/TREAT_DMD/). We analysed genetic data for 7149 DMD mutations held
within the database. 5682 large mutations were observed (80% of total mutations), of which
4894 (86%) were deletions (1 exon or larger), and 784 (14%) were duplications (1 exon or
larger). There were 1445 small mutations (smaller than 1 exon, 20% of all mutations), of
which 358 (25%) were small deletions and 132 (9%) small insertions and 199 (14%) affected
the splice sites. Point mutations totalled 756 (52% of small mutations) with 726 (50%)
nonsense mutations and 30 (2%) missense mutations. Finally, 22 (0.3%) mid-intronic
mutations were observed. In addition, mutations were identified within the database that
would potentially benefit from novel genetic therapies for DMD including stop codon read-
through therapies (10% of total mutations) and exon skipping therapy (80% of deletions and
55% of total mutations).
Key Words: DMD; Duchenne muscular dystrophy; TREAT-NMD; rare disease registries
This article is protected by copyright. All rights reserved. 6
Introduction
Duchenne muscular dystrophy (DMD) is a severe, X-linked, progressive neuromuscular
disease caused by mutations in the DMD gene (DMD; MIM# 310200) (Hoffman, et al., 1988).
Mutations in this gene give rise to two forms of muscular dystrophy depending on whether
the translational reading frame is lost or maintained: severe DMD, due to out of frame
mutations leading to loss of protein function, or a milder form of muscular dystrophy known
as Becker muscular dystrophy (BMD; MIM# 300376), caused by a reduction in the amount
and/or size of dystrophin protein due to frame maintaining mutations (Koenig, et al., 1989).
The DMD gene is the largest known gene in humans, spanning 2.3 Mb of genomic DNA. The
coding sequence spans 11 Kb and is made up of 79 exons (Ahn and Kunkel, 1993). Many
different types of mutation have been described for DMD including large deletions and
duplications, point mutations and small rearrangements.
DMD has a prevalence of 21.2/100,000 school aged boys (Mah, et al., 2014). Current care
recommendations (specifically, the use of corticosteroids, cardiac medications, and assisted
ventilation) improve outcomes and quality of life but do not modify the underlying
progression of the disease (Hoffman, et al., 2012; Sejerson, et al., 2009). Potential treatment
strategies centre primarily on targeted mitigation of the causative genetic mutation. One
example of a genetic based potential therapy is non-sense stop codon read-through therapy
(Hirawat, et al., 2007; Howard, et al., 2000; Wagner, et al., 2001; Welch, et al., 2007). These
treatments, include aminoglycosides and ataluren (previously PTC124), and work by
selectively inducing ribosomal read-through of premature stop codons but not normal stop
codons. Specific non-sense mutations exist in DMD patients leading to premature stop
codons (TGA, TAG and TAA) and would potentially benefit from this therapy. Translarna
recently obtained conditional marketing authorization from the European Medicine Agency
(EMA) for use in ambulant Duchenne patients over 5 years of age, and as such is the first
drug to be approved for DMD.
This article is protected by copyright. All rights reserved. 7
A further example is the exon skipping approach. Exon skipping aims to moderate disease
progression by taking advantage of the knowledge that internally deleted dystrophins (seen in
BMD) can be partially functional (Aartsma-Rus, et al., 2009; Beroud, et al., 2007; van
Ommen and Aartsma-Rus, 2013). Significant research has been undertaken in the field of
exon skipping to restore the open reading frame of dystrophin transcripts resulting in the
production of partly functional dystrophin protein (Aartsma-Rus, et al., 2009; van Ommen, et
al., 2008). Exon skipping is achieved by the use of antisense oligonucleotides (AONs) that
specifically bind to and hide exons from the splicing machinery, leading to an in-frame
mRNA without this exon and giving rise to internally deleted dystrophin proteins as seen in
BMD patients (Aartsma-Rus, et al., 2003; Aartsma-Rus, et al., 2004; Arechavala-Gomeza, et
al., 2007; Gurvich, et al., 2008; McClorey, et al., 2006; Surono, et al., 2004; Takeshima, et al.,
2001). Since DMD has a relatively high rate of new mutations (1 in 3 mutations is new), most
patients have unique mutations (Aartsma-Rus, et al., 2006; Tuffery-Giraud, et al., 2009).
However, approximately 60%-65% of all DMD patients carry a deletion of one or more
exons, with a tendency to cluster between exons 45 and 55 (Aartsma-Rus, et al., 2006;
Tuffery-Giraud, et al., 2009). Furthermore, while the location of the breakpoints in introns
will differ for patients with (e.g.) a deletion of exon 48-50, these deletions will give rise to
identical transcripts. Therefore, the skipping of certain exons would be applied to relatively
large numbers of patients.
Understanding the type and frequency of patient specific mutations that give rise to DMD
associated phenotypes is an invaluable tool both for genetic diagnosis, basic scientific
research and improved clinical care, potentially leading to new treatments for the disease.
Currently the TREAT-NMD DMD Global database contains over 7000 (7149 as of
November 2013) mutations (http://umd.be/TREAT_DMD/). Locus specific databases
(LSDBs) allow for the collection, organization, storage and analysis of genetic variants of
This article is protected by copyright. All rights reserved. 8
disease. LSDBs collect all published and unpublished mutations for a specific gene along
with complete clinical and phenotypic information. Additional confidence exists in these
datasets due in part to the role of experts or “curators”. Curators validate the data held within
the database and significantly reduce error rates (Beroud, et al., 2005; Cotton, et al., 2008). In
the case of LSDBs for DMD, a number of databases exist including, the Leiden muscular
dystrophy pages, (http://www.dmd.nl/) in the Netherlands (Aartsma-Rus, et al., 2006), and
the UMD-DMD, (http://www.umd.be/DMD/) in France (Cotton, et al., 2008). We here report
a new global mutation database for DMD, and outline how this can be used for genetic
analysis and development of genetic therapies.
Methods
A new global database for DMD (TREAT-NMD DMD Global database) based on the French
UMD-DMD system has been developed with TREAT-NMD collaboration. TREAT-NMD
was initially established as an EU funded „network of excellence‟ with the remit of
„reshaping the research environment‟ in the neuromuscular field ([http://www.treat-nmd.eu/],
2013; Bushby, et al., 2009). Standardised mutation (DMD mutations) specific data based on
TREAT-NMD mandatory and highly encouraged items from the national TREAT-NMD
DMD registries (Bladen, et al., 2013) were transferred to the global DMD database via a
secure File Transfer Protocol (FTP) transfer in November 2013, in order to provide a single
cohort of genetic and clinical variants (Figure 1). Analysis of DMD genetic mutations was
then carried out for the 7149 patient data sets held within the TREAT-NMD DMD Global
database. HGVS nomenclature was used throughout (http://www.hgvs.org/mutnomen/).
This article is protected by copyright. All rights reserved. 9
Results
The TREAT-NMD DMD Global database currently contains 7149 Duchenne Muscular
Dystrophy (DMD) mutations. There were 5684 large mutations (80%), of which 4894 (86%)
were deletions (1 exon or larger), and 784 (14%) were duplications (1 exon or larger) (Table
1). There were 1445 small mutations (20% of all mutations), of which 358 (25%) were
deletions (smaller than 1 exon) and 132 (9%) were duplications (smaller than one exon); 199
(14%) splice site mutations were recorded. Point mutations totalled 756 (10% of all mutations,
52% of small mutations) with 726 nonsense mutations (10% of all mutations, 50% of small
mutations) and 3 missense mutations (<1% of all mutations, 2% of small mutations). Finally
22 (less than 1% of all mutations, 0.3% of small mutations) mid-intronic mutations were
observed (Table 1).
Large Mutations
Large deletions
4894 large deletions were reported and accounted for 68% of total mutations. Figure 2a,
highlights the ten most commonly reported (observed more than 100 times) large deletions
within the database. The most common large deletion was a deletion of exon 45, which was
recorded 316 times in the database (4% of deletions). Distribution of large deletions was
non-random with the majority of large deletions (80%) covering either the distal region
mutation hot spot of the dystrophin gene (exons 45-55) or the proximal region (exons 2-20)
(Figure 3).
This article is protected by copyright. All rights reserved. 10
Large duplications
784 large duplications were reported and accounted for 11% of total mutations. Figure 2b,
shows the eight most commonly reported large duplications (observed more than 10 times).
The most common large duplication was duplication of exon 2 (11% of duplications).
Distribution of large duplications was non-random with most large duplications involving
distal or proximal mutation hot spots (65%) (Figure 3).
Single exon deletions and duplications
The five most frequent single exon deletions recorded in the database (all reported more than
100 times) were, deletion of exon 45 (4%), 51 (3%), 44 (3%), 52 (3%) and 50 (2%). Single
exon duplications occurred less frequently than single exon deletions. Duplication of exon 2
was the most frequent and was reported 50 times, while the second most frequent single exon
duplication was duplication of exon 17 and was reported 11 times in the database.
Small Mutations
The database contained 1445 small lesions and included deletions (smaller than 1 exon; 355,
25%), duplications (smaller than one exon; 132, 9%), 199 (14%) splice site mutations and
756 (52%) point mutations, 726 (50%) nonsense mutations, 30 (2%) missense mutations and.
22 (0.3%) mid-intronic mutations (Table 1). Small deletions and mutations ranged in size
from two nucleotides (occurring 85 times) to 111 nucleotides (occurring twice).
This article is protected by copyright. All rights reserved. 11
Nonsense mutations
Non-sense mutations represented 50% of the small mutations in the database and 10% of total
mutations. Transition mutational events (70%) were more common than transversions (30%),
with the C-to-T substitution being the most frequent (90%).
Potential DMD Therapies
Non-sense stop codon read-through therapy has obtained conditional marketing authorization
(Hirawat, et al., 2007; Howard, et al., 2000; Wagner, et al., 2001; Welch, et al., 2007). This
treatment selectively induces ribosomal read-through of premature stop codons but not
normal stop codons. Mutations were identified within the database that would potentially
benefit from this therapy. These included 317 mutations (4% of overall mutations) with a
premature TGA stop codon, 215 (3%) with a TAG stop codon and 194 (3%) with a TAA stop
codon.
Exon skipping technology takes advantage of the fact that internally deleted dystrophins,
often seen in BMD, can be partially functional. Mutations were identified within the database
that would potentially benefit from exon skipping therapy. The top ten exon skips which
would be applicable to the largest group of patients were skipping of exon 51 (14% of total
mutations/21% of deletions), 53 (10%/15%), 45 (9%/13%), 44 (7%/11%),43 (7%/11%),
46(5%/7%), 50(4%/6%), 52(4%/5%), 55(3%/4%) and 8(2%/3%) respectively shown in Table
2. It is important to point out that the applicability of exon skipping of certain exons reduces
once antisense oligonucleotides targeting other exons have been developed. For example, the
reading frame of exon 52 deletions can be restored by skipping exon 51 or by skipping exon
53. However, once an antisense oligonucleotide for exon 51 has been developed and
approved for clinical use, the additional applicability of exon 53 skipping is then lower than
the a priori applicability, since it now only applies to 8% of mutations rather than 10%,
because the exon 52 deletion has already been rescued by exon 51 skipping. The top 10 of
exon skips and their added applicability (i.e. taking this adjustment into account) is shown in
(Table 2).
This article is protected by copyright. All rights reserved. 12
CpG sites
Substitutions involving a CpG dinucleotide accounted for 31% (233/756) of point mutations
within the database. The CpG dinucleotide has been shown to undergo oxidative deamination
of 5-methyl cytosine resulting in a mutational “hot spot” and mutation rates an order of
magnitude higher than normally expected (Akalin, et al., 1994; Flanigan, et al., 2009;
Krawczak, et al., 1998).
Geography and DMD mutations
Regardless of geographical location (determined by continent), large deletions were by far
the most commonly observed (64% in Oceania to 88% in Africa) mutation followed by large
duplications (5% in Africa to 12% in Europe). The number of small mutations was generally
more variable (7% in Africa to 22% in Oceania) but this variability is likely explained by the
fact that not all countries routinely assay for point mutations and other small lesions and
indeed numbers of patients were significantly smaller for example in Africa compared to
Europe (Figure 4.).
This article is protected by copyright. All rights reserved. 13
Discussion
Databases
Resources existed for DMD prior to the creation of the TREAT-NMD DMD Global database,
the Leiden muscular dystrophy pages, (http://www.dmd.nl/) in the Netherlands (Aartsma-Rus,
et al., 2006), and the UMD-DMD, (http://www.umd.be/DMD/) in France (Cotton, et al.,
2008). For both the previously existing databases, bias of recorded mutations has been an
inherent problem due in part to the method used to determine the mutation. Historically,
detection of deletions and duplications was easier than detection of point mutations and other
small rearrangements leading to an overrepresentation of such mutations in the literature and
indeed a possible underrepresentation of point mutations and other small rearrangements.
However, this bias is becoming less of an issue due to current diagnostic techniques that are
widely available (Flanigan, et al., 2009; Prior and Bridgeman, 2005). Also, while initially,
the most commonly occurring mutations were recorded; now there is potentially a bias
towards only novel mutations being recorded (e.g.) in the Leiden database. In addition to this,
the UMD-DMD database is specific to France and could potentially include a bias for
mutations observed with higher or lower frequencies only in France. The new TREAT-NMD
DMD Global database houses what we believe to be the single largest cohort of verified
DMD mutations in the world and was established to collect and compare and molecular
mutations found within this patient group. Mutational analysis of the database illustrates the
allelic heterogeneity of the DMD gene. Indeed, one third of all DMD mutations occur de
novo (NG, 1993).
This article is protected by copyright. All rights reserved. 14
Analysis and comparisons
Analysis of the TREAT-NMD DMD Global database revealed that large deletions were the
most prevalent genetic mutation recorded and accounted for 68% of the total mutations
analysed, deletion of exon 45 being the single most common large deletion (reported 316
times). These results are similar to both the French UMD database (Tuffery-Giraud, et al.,
2009) with 62% of the mutations being large deletions and the Leiden database (Aartsma-Rus,
et al., 2006), where 72% of the mutations are large deletions. In the Leiden database and the
TREAT-NMD DMD Global databases, deletion of exon 45 was the most common deletion,
making up 4% of the mutations in the TREAT-NMD DMD Global database and 2% of the
Leiden database. Large duplications accounted for 11% of mutations in the TREAT-NMD
DMD Global database compared to 13% in the French UMD database and 8% in the Leiden
database. The most commonly occurring large duplication was duplication of exon 2 in all
three databases. Small rearrangements accounted for 20% of the TREAT-NMD DMD Global
database which was similar to the French UMD database (26%) and the Leiden database
(20%). Point mutations and nonsense mutation were the most prevalent small rearrangements
with non-sense mutations accounting for 50% of the small rearrangements in the TREAT-
NMD DMD Global database, compared to 40% in the French UMD database and 50% in the
Leiden database. Large deletions and duplications follow a non-random distribution with 78%
of them including either the proximal or distal mutation hot spots (Aartsma-Rus, et al., 2006;
Koenig, et al., 1989; Prior and Bridgeman, 2005).
This article is protected by copyright. All rights reserved. 15
Reading frame rule
The majority of the reported (DMD) mutations in the TREAT-NMD DMD Global database
resulted in frame-shift mutations (93%). Mutations not following the reading-frame rule in
the TREAT-NMD DMD Global database accounted for 7% of total mutations compared with
4% in the UMD-DMD database and 9% in the Leiden database.
Potential DMD Therapies
Several potential novel DMD therapies exist and are focused on the mitigation of the
underlying genetic defect. The two most promising examples are non-sense read through and
exon skipping. Mutations were identified within the database that would potentially benefit
from this stop codon read-through therapy (10% of mutations). Exon skipping mutations
were identified within the database that would potentially benefit from exon skipping therapy
(55% of total mutations and 80% of deletions).
Understanding the type and frequency of patient specific mutations that give rise to DMD
associated phenotypes will potentially lead to personalized (targeted/precision) therapies.
DMD essentially serves as a paradigm for this type of treatment and ultimately could lead the
way to similar approaches in other rare diseases and indeed in more common disorders.
This article is protected by copyright. All rights reserved. 16
Acknowledgments
This work was supported by TREAT-NMD operating grants, FP6 LSHM-CT-2006-036825,
20123307 UNEW_FY2013 and AFM 16104. Further support came from the European
Union Seventh Framework Programme (FP7/2007-2013) under grant agreement No. 305444
(RD-Connect) and 305121 (Neuromics).
The authors would like to acknowledge the families of those living with Duchenne muscular
dystrophy who have been instrumental in the formation of the DMD national registries. We
also acknowledge former and current members of the TREAT-NMD office at the Institute of
Genetic Medicine in Newcastle including Stephen Lynn, Emma Heslop and Rachel
Thompson. We also extend our thanks to the members of the TREAT-NMD executive
committee: Hanns Lochmuller, Annemieke Aartsma-Rus, Anna Ambrosini, Filippo Buccella,
Kevin Flanigan, Eric Hoffman, Janbernd Kirschner, Eugenio Mercuri, Ichizo Nishino, Kathy
North, Jes Rahbek and Thomas Sejersen. We also aknowledge the members of the current
TGDOC: Jan Verschuuren (Chair), Hugh Dawkins (Chair elect), Anna Ambrosini, Svetlana
Artemieva, Alexander N. Baranov, Farhad Bayat, Christophe Béroud, Ria Broekgaarden,
Filippo Buccella, Craig Campbell, Nick Catlin, Monica Ensini, Pat Furlong, Kevin Flanigan,
Ole Gredal, Lauren Hache, Serap İnal, Jacqueline Jackson, Pierre-Yves Jeannet, Anna
Kaminska, A. Ayse Karaduman, Veronika Karcagi, En Kimura, Janbernd Kirschner, Jaana
Lähdetie, Hanns Lochmüller, Vitaliy Matyushenko, Vedrana Milic-Rasic, Violeta Mihaylova,
Marie-Christine Ouillade, Ian Murphy, Miriam Rodrigues, Rosario dos Santos, Pascale
Saugier-Veber, Inge Schwersenz, Thomas Sejersen, Rasha El Sherif, Eduardo Tizzano,
Isabela Tudorache, Sylvie Tuffery-Giraud, Jen Wang, Simon Woods, W. Ludo van der Pol,
Peter Van den Bergh, Petr Vondráček.
This article is protected by copyright. All rights reserved. 17
Conflicts of interest
Professor Hanns Lochmuller was elected chair of the TREAT-NMD Alliance in April 2012
and is the previous chair of the oversight committee.
Professor Lochmuller has a financial interest/arrangement with Pfizer, Ultragenyx and
GlaxoSmithKline (Research grant investigator).
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Figure 1. Upload of data from national TREAT-NMD DMD registries to Global
database. Standardised aggregate data from the national TREAT-NMD DMD registries was
transferred to the global DMD database via a secure FTP transfer, in order to provide a single
cohort of genetic and clinical variants.
This article is protected by copyright. All rights reserved. 21
Figure 2. Most commonly reported large mutations. Most commonly reported large
deletions (recorded 100 times or more) (a) and large duplications (recorded 10 times or more)
(b) in the TREAT-NMD DMD Global database.
This article is protected by copyright. All rights reserved. 22
Figure 3. Distribution of the most common large deletion and duplication on the DMD
gene.
This article is protected by copyright. All rights reserved. 23
Figure 4. Geography and DMD mutations. Distribution of DMD mutation types stratified
by continent.
This article is protected by copyright. All rights reserved. 24
Table 1. Type and Frequency of mutations held within the TREAT-NMD DMD
Global database
TOTAL
7149
% of total mutations
Large mutations
5682
79
Large deletions (>=1 exon)
4894
68
Large duplications (>=1 exon)
784
11
Small mutations
1445
20
Small deletions (<1 exon)
358
5
Small insertions (<1 exon)
132
2
Splice sites (<10 bp from exon)
199
3
Point mutations
756
11
Nonsense
726
10
Missense
30
0.4
Mid-intronic mutations
22
0.3
This article is protected by copyright. All rights reserved. 25
Table 2. Overview of DMD exons
(a) Overview of exons for which single exon skipping would be applicable to
the largest groups of patients.
(b) Adjusted overview of applicability of single exon skipping.
