Author:
Magri Francesca,Del Bo Roberto,D'Angelo Maria G,Govoni Alessandra,Ghezzi Serena,Gandossini Sandra,Sciacco Monica,Ciscato Patrizia,Bordoni Andreina,Tedeschi Silvana,Fortunato Francesco,Lucchini Valeria,Cereda Matteo,Corti Stefania,Moggio Maurizio,Bresolin Nereo,Comi Giacomo P
Abstract
Abstract
Background
Duchenne and Becker Muscular dystrophies (DMD/BMD) are allelic disorders caused by mutations in the dystrophin gene, which encodes a sarcolemmal protein responsible for muscle integrity. Deletions and duplications account for approximately 75% of mutations in DMD and 85% in BMD. The implementation of techniques allowing complete gene sequencing has focused attention on small point mutations and other mechanisms underlying complex rearrangements.
Methods
We selected 47 patients (41 families; 35 DMD, 6 BMD) without deletions and duplications in DMD gene (excluded by multiplex ligation-dependent probe amplification and multiplex polymerase chain reaction analysis). This cohort was investigated by systematic direct sequence analysis to study sequence variation. We focused our attention on rare mutational events which were further studied through transcript analysis.
Results
We identified 40 different nucleotide alterations in DMD gene and their clinical correlates; altogether, 16 mutations were novel. DMD probands carried 9 microinsertions/microdeletions, 19 nonsense mutations, and 7 splice-site mutations. BMD patients carried 2 nonsense mutations, 2 splice-site mutations, 1 missense substitution, and 1 single base insertion. The most frequent stop codon was TGA (n = 10 patients), followed by TAG (n = 7) and TAA (n = 4). We also analyzed the molecular mechanisms of five rare mutational events. They are two frame-shifting mutations in the DMD gene 3'end in BMD and three novel splicing defects: IVS42: c.6118-3C>A, which causes a leaky splice-site; c.9560A>G, which determines a cryptic splice-site activation and c.9564-426 T>G, which creates pseudoexon retention within IVS65.
Conclusion
The analysis of our patients' sample, carrying point mutations or complex rearrangements in DMD gene, contributes to the knowledge on phenotypic correlations in dystrophinopatic patients and can provide a better understanding of pre-mRNA maturation defects and dystrophin functional domains. These data can have a prognostic relevance and can be useful in directing new therapeutic approaches, which rely on a precise definition of the genetic defects as well as their molecular consequences.
Publisher
Springer Science and Business Media LLC
Subject
Genetics (clinical),Genetics
Reference40 articles.
1. Davies KE, Smith TJ, Bundey S, et al: Mild and severe muscular dystrophy associated with deletions in Xp21 of the human × chromosome. J Med Genet. 1988, 25: 9-13. 10.1136/jmg.25.1.9.
2. Emery AE: Population frequencies of inherited neuromuscular diseases--a world survey. Neuromuscul Disord. 1991, 1: 19-29. 10.1016/0960-8966(91)90039-U.
3. Emery AE: Some unanswered questions in Duchenne muscular dystrophy. Neuromuscul Disord. 1994, 4 (4): 301-3. 10.1016/0960-8966(94)90065-5.
4. Beggs AH, Hoffman EP, Snyder JR, et al: Exploring the molecular basis for variability among patients with Becker muscular dystrophy: dystrophin gene and protein studies. Am J Hum Genet. 1991, 49 (1): 54-67.
5. Curtis , Haggerty : Deletion and duplication analysis in males affected with Duchenne or Becker muscular dystrophy. Methods in molecular medicine. Edited by: Anderson LVB. 2001, Totowa NJ: Humana Press, 43: 53-84.
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