BACKGROUND: X-linked dilated cardiomyopathy (XLCM) has previously been shown to be due to mutations in the dystrophin gene, which is located at Xp21. Mutations in the 5' portion of the gene, including the muscle promoter, exon 1, and the exon 1-intron 1 splice site, have been reported previously. The purpose of this study was to analyze the originally described family with XLCM (and other) for dystrophin mutations. METHODS AND RESULTS: Polymerase chain reaction (PCR) was used to amplify genomic DNA, and reverse-transcriptase PCR amplified cDNA from RNA obtained from heart and lymphoblastoid cell lines. Primers to the muscle promoter, brain promoter, and Purkinje cell promoter were designed, in addition to the exon 1 to exon 14 regions of dystrophin. Single-strand conformation polymorphism analysis was used for mutation detection, and DNA sequencing defined the mutation. Protein modeling was used for amino acid and secondary structure analysis. A missense mutation in exon 9 at nucleotide 1043 was identified that causes an alanine to be substituted for threonine, a highly conserved amino acid, at position 279 (T279A). This mutation results in a change in polarity in the evolutionarily conserved first hinge region (H1) of the protein and substitution of a beta-sheet for alpha-helix in this portion of the protein, destabilizing the protein. CONCLUSIONS: A novel missense mutation in exon 9 of dystrophin causing an abnormality at H1 leads to the cardiospecific phenotype of XLCM.
BACKGROUND:X-linked dilated cardiomyopathy (XLCM) has previously been shown to be due to mutations in the dystrophin gene, which is located at Xp21. Mutations in the 5' portion of the gene, including the muscle promoter, exon 1, and the exon 1-intron 1 splice site, have been reported previously. The purpose of this study was to analyze the originally described family with XLCM (and other) for dystrophin mutations. METHODS AND RESULTS: Polymerase chain reaction (PCR) was used to amplify genomic DNA, and reverse-transcriptase PCR amplified cDNA from RNA obtained from heart and lymphoblastoid cell lines. Primers to the muscle promoter, brain promoter, and Purkinje cell promoter were designed, in addition to the exon 1 to exon 14 regions of dystrophin. Single-strand conformation polymorphism analysis was used for mutation detection, and DNA sequencing defined the mutation. Protein modeling was used for amino acid and secondary structure analysis. A missense mutation in exon 9 at nucleotide 1043 was identified that causes an alanine to be substituted for threonine, a highly conserved amino acid, at position 279 (T279A). This mutation results in a change in polarity in the evolutionarily conserved first hinge region (H1) of the protein and substitution of a beta-sheet for alpha-helix in this portion of the protein, destabilizing the protein. CONCLUSIONS: A novel missense mutation in exon 9 of dystrophin causing an abnormality at H1 leads to the cardiospecific phenotype of XLCM.
Authors: Robert M Weiss; Richard E Kerber; Jane K Jones; Carrie M Stephan; Christina J Trout; Paul D Lindower; Kimberly S Staffey; Kevin P Campbell; Katherine D Mathews Journal: J Am Soc Echocardiogr Date: 2010-06-19 Impact factor: 5.251
Authors: Sunil K Kakarla; Kevin M Rice; Anjaiah Katta; Satyanarayana Paturi; Miaozong Wu; Madhukar Kolli; Saba Keshavarzian; Kamran Manzoor; Paulette S Wehner; Eric R Blough Journal: J Gerontol A Biol Sci Med Sci Date: 2010-01-07 Impact factor: 6.053
Authors: Matthew R G Taylor; Lisa Ku; Dobromir Slavov; Jean Cavanaugh; Mark Boucek; Xiao Zhu; Sharon Graw; Elisa Carniel; Carl Barnes; Dianna Quan; Ryan Prall; Mark A Lovell; Gary Mierau; Patsy Ruegg; Naresh Mandava; Michael R Bristow; Jeffrey A Towbin; Luisa Mestroni Journal: J Hum Genet Date: 2007 Impact factor: 3.172