Point mutations in Czech DMD/BMD patients and their phenotypic outcome.
Duchenne and Becker muscular dystrophies (DMD/BMD) are associated with mutations in the DMD gene. We determined the mutation status of 47 patients with dystrophinopathy without deletion or duplication in the DMD gene by screening performed by reverse transcription-PCR, protein truncation test, and DNA sequencing. We describe three patients with a mutation creating a premature termination codon (p.E55X, p.E1110X, and p.S3497PfsX2) but with a mild phenotype, which present three different ways of rescuing the DMD phenotype. In one patient we detected the insertion of a repetitive sequence AluYa5 in intron 56, which led to skipping of exon 57. Further, using quantitative analysis of DMD mRNA carrying various mutated alleles, we examine levels of mRNA degradation due to nonsense mediated mRNA decay. The quantity of dystrophin mRNA is different depending on the presence of a mutation leading to a premature termination codon, and position of the analysed mRNA region with respect to its 5' end or 3' end. Average relative amounts of DMD mRNAs carrying a premature termination codon is 48% and 17%, when using primers amplifying the 5' and 3' cDNA regions, respectively.
Centre of Molecular Biology and Gene Therapy, University Hospital Brno and Masaryk University, Brno, Czech Republic.
Jana
J
Sedlácková
Petr
P
Vondrácek
Markéta
M
Hermanová
Josef
J
Zámecník
Zuzana
Z
Hrubá
Jana
J
Haberlová
Josef
J
Kraus
Tat'ána
T
Maríková
Petra
P
Hedvicáková
Stanislav
S
Vohánka
Lenka
L
Fajkusová
D001483:Base Sequence; D018153:Czech Republic; D004252:DNA Mutational Analysis / Q000379:methods; D016189:Dystrophin / Q000235:genetics* / Q000378:metabolism; D005091:Exons; D005260:Female; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D020388:Muscular Dystrophy, Duchenne / Q000235:genetics*; D010641:Phenotype; D017354:Point Mutation; D012333:RNA, Messenger / Q000378:metabolism
C484258:DMD protein, human; D016189:Dystrophin; D012333:RNA, Messenger