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(Circulation. 1997;95:2434-2440.)
© 1997 American Heart Association, Inc.

Articles

Evidence for a Dystrophin Missense Mutation as a Cause of X-Linked Dilated Cardiomyopathy

Rocio Ortiz-Lopez, MS; Hua Li, PhD; Jason Su, DO; Veronica Goytia, BS; Jeffrey A. Towbin, MD

the Departments of Pediatrics (R.O.-L., H.L., J.S., V.G., J.A.T.) and Molecular and Human Genetics (J.A.T.), Baylor College of Medicine, Houston, Tex.

	Abstract

Top Abstract Introduction Methods Results Discussion References

 
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 others) 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 ß-sheet for -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.

Key Words: cardiomyopathy • genetics • dystrophin • mutation

	Introduction

Top Abstract Introduction Methods Results Discussion References

 
Dilated cardiomyopathy, the most common form of primary myocardial disease, is a major cause of morbidity and mortality and a leading indication for cardiac transplantation.^{1 2 3} Approximately 20% to 30% of all cases of DCM are inherited,^{4 5} with autosomal dominant transmission being most common; autosomal recessive, X-linked, and mitochondrial inheritance patterns have also been described.^{6 7}

XLCM is a severe and rapidly progressive myocardial disease that affects young men in their teens or early twenties.⁸ Typically, affected males present with severe congestive heart failure that results in death or cardiac transplantation within 1 to 2 years of diagnosis. Clinically, XLCM appears to be identical to other causes of DCM except for its X-linked transmission^{6 8 9} and elevated serum CK-MM without evidence of clinical skeletal myopathy. Female carriers with XLCM may manifest symptoms later in life, usually in the fifth decade, but the disease is mild and progresses slowly.⁸

Molecular genetic linkage to the 5' end of the dystrophin gene at Xp21 was previously reported by Towbin et al.⁹ In addition, N-terminal dystrophin antibody against cardiac tissue protein extracts showed decreased abundance (or absence) of dystrophin, whereas C-terminal antibody immunoblots were normal.⁹ Dystrophin antibody against the rod domain also demonstrated low abundance of protein.¹⁰ Immunoblots using N-terminal, C-terminal, and rod domain dystrophin antibodies against skeletal muscle protein demonstrated normal dystrophin, however.^{9 10}

The dystrophin gene, which causes DMD and the milder allelic form, BMD, is the largest gene identified in humans thus far, covering >2.5 Mb and having 79 exons.^{11 12} The corresponding 14-kb dystrophin mRNA is expressed predominantly in skeletal, cardiac, and smooth muscle, although lower levels also appear in brain. Transcription of dystrophin in different tissues is regulated from either the P_B,^{13 14 15} which is active predominantly in neuronal cells; the P_M,¹⁶ which is active in differentiated myogenic cells and glial cells; and the P_P,^{17 18} which is active in cerebellum. The resultant protein, dystrophin,^{12 19} is a 427-kD protein localized to the cytoplasmic face of the sarcolemma, colocalizing with ß-spectrin and vinculin at the sarcolemma.²⁰ The C-terminal region of dystrophin is bound to the protoplasmic half of the plasmalemma. Thus, dystrophin forms an intricate part of the muscle cytoskeleton and may function to link the normal contractile apparatus to the sarcolemma. In skeletal and cardiac muscle, the C-terminal domain is bound to a large oligomeric glycoprotein complex of six novel proteins localized to the sarcolemma^{21 22 23 24} ; the N-terminus attaches to actin.

In DMD, the levels of all members of the oligomeric glycoprotein complex are reduced.²⁵ In BMD, however, there is only a general mild reduction in these proteins.²⁶ It is believed that dystrophin localizes or stabilizes this oligomeric protein complex.²⁷ Without dystrophin, the complex is unable to organize properly, and consequently the linkage between the extracellular matrix and sarcolemma is disrupted.²⁸

Muntoni et al²⁹ reported a deletion within the P_M and E1 of dystrophin in a family with DCM, X-linked inheritance, and mild abnormalities of skeletal muscle histology and dystrophin immunohistochemical staining. They showed this mutation to be the cause of disease in this family and speculated that this deletion was the responsible mutation in all patients with XLCM. More recently, these authors^{30 31} also confirmed the dystrophin protein findings of Towbin et al.^{9 10} Holder et al³² described a mutation in the muscle promoter that potentially affects cardiac-specific regulatory sequences and therefore could selectively cause DCM without significant skeletal myopathy. This mutation is quite uncommon in BMD and DMD patients screened for dystrophin deletions,³³ however. Since previous reports of P_M-E1 mutations in other unrelated patients were usually associated only with mild skeletal muscle disease without cardiac disease,^{13 34} doubt arose that this mutation was the only mutation leading to XLCM. In fact, only the patient reported by Yoshida et al³⁵ with an E1 deletion and normal P_M had DCM. In addition, Towbin and Ortiz-Lopez³⁶ reported on three families with documented XLCM in whom P_M-E1 was normal. More recently, Milasin et al³⁷ reported a point mutation in the 5' splice site of dystrophin E1-I1 boundary causing XLCM clinically and abolishing expression of dystrophin in cardiac tissue. Therefore, XLCM appears to be due to various different mutations in the dystrophin gene. In this report, we describe a novel missense mutation in the 5' end of dystrophin in the originally described family with XLCM,⁸ and we also provide further data that suggest that there is allelic heterogeneity for XLCM, because two other families with XLCM studied here have none of the reported dystrophin mutations.

	Methods

Top Abstract Introduction Methods Results Discussion References

 
Families and Linkage Analysis
Clinical evaluation and linkage analysis of the three families (XLCM-1, XLCM-2, and XLCM-3) were previously described.^{8 9}

Control Individuals
One hundred unrelated and unaffected individuals (50 male, 50 female; 50 black and 50 white), as determined by history, physical examination, and echocardiography, were analyzed. After informed consent was obtained, blood for lymphoblastoid cell line immortalization³⁸ was obtained.

Procedures
RT-PCR. RNA was prepared from lymphoblastoid cell lines³⁸ or cardiac tissue as previously described.³⁹ Briefly, 2 µg of total RNA was reverse transcribed in a 20-µL reaction with 5 µg of random hexamer primers (Gibco-BRL) and 100 U murine Moloney leukemia virus RT at 37°C in the buffer provided by the supplier (Gibco-BRL). Of the RT reaction, 2 µL was used for each PCR reaction in 25 µL of 1.5 mmol/L MgCl₂, 67 mmol/L Tris-HCl (pH 8.8), 16.6 mmol/L ammonium sulfate, 0.01% Tween-20, 200 µmol/L of each dNTP, 25 pmol of each primer, and 1 U Taq DNA polymerase (Promega). PCR conditions included 94°C for 3 minutes, 30 cycles of 92°C for 1 minute, 58°C for 1 minute, 72°C for 1 minute, and a final extension of 72°C for 5 minutes. The PCR products were visualized on 2% agarose gel. The primers used for the amplification of the first 14 exons of dystrophin cDNA were derived from the reported dystrophin sequence¹¹ ; primers used for RT-PCR were exon 1F, 5'-TGGGAAGAAGTAGAGGACTGTTATG-3'; exon 5R, 5'-TTGACCTGCCAGTGGAGGAT-3'; exon 4F, 5'-GCA CTGCGGGTTTTGCAGAA-3'; exon 7R, 5'-GAATGCATTCCAGTCGTTGTGT-3'; exon 6F, 5'-TGAATGCTCTC ATCCAGTCATAG-3'; exon 10R, 5'-CTCTCCATCA ATGAACTGCC-3'; exon 10F, 5'-CATTGCAAGCACAAG GAGAG-3'; and exon 13R, 5'-CAGTTGCGTGATCTCCACTA GATTC-3'.

PCR amplification of genomic DNA. The primers used to amplify sequences of the P_B, P_M, P_P, and exon-intron junctions were designed with the previously reported sequences^{13 14 15 16 17} and conditions. The primers used for promoter amplification included the following: P_M, 5'-GAAGATCTAGACAGTGGAT ACATAACAAATGCATG-3'; E1_R, 5'-TTCTCCGAAG GTAATTGCCTCCCAGATCTGAGTCC-3'; P_BF, 5'-GAA GATCTATATTTTACAACGCAGAAATGTGG-3'; P_BR, 5'-CTTCCATGCCAGCTGTTTTTCCTGTCACTC-3'; P_pF, 5'-CAGCCTCCGCAGAATTTGAAATG-3'; and exon 2R, 5'-CTTAGAAAATTGTGCATTTACCCA-3'.

Multiplex PCR. Multiplex PCR was performed with the five primer pairs described by Beggs et al⁴⁰ and nine primer pairs described by Chamberlain et al⁴¹ ; an additional set of primers designed to amplify exon 9 (F, 5'-GAATTCCTCTCGCAGAT CACG-3'; R, 5'-GTAAATGTTGACAGACCTGTG-3') was also added to each. This multiplex PCR was performed under the following conditions: 94°C for 6 minutes, 94°C for 30 seconds, 54°C for 30 seconds, 65°C for 4 minutes (25 cycles), and 65°C for 7 minutes. Amplification products were visualized on a 3% agarose gel with ethidium bromide under ultraviolet light.

SSCP. Mutation analysis was performed by the method of Orita et al.⁴² PCR primers were designed to amplify a region including the 3' portion of intron 8 and the 3' end of exon 9. This region flanked the normal, polymorphic, or mutated sequence of exon 9 (Fig 1A, primers a through d). Radioactive PCR was performed with 100 ng genomic DNA in a 10-µL reaction containing 2.5 mmol/L MgCl₂, 10 pmol of each primer, 0.05 µCi [-³²P]dCTP, 0.5 U Taq polymerase, and 30 rounds of amplification (92°C for 45 seconds, 60°C for 45 seconds, and 72°C for 1 minute). After PCR amplification, the samples were denatured by addition of 5 µL formamide dye (95% formamide, 20 mmol/L EDTA, 0.05% bromophenol blue, and 0.05% xylene cyanol) at 85°C for 5 minutes. After 10 minutes of cooling on ice, 3 µL of sample was electrophoresed on a nondenaturing 10% polyacrylamide:bisacrylamide (50:1) gel at 8 W over 24 hours in a 4°C cold room. Bands were visualized by exposure of the dried gels to Kodak X-AR film.

View larger version (35K): [in this window] [in a new window]   Figure 1. A, PCR analysis of dystrophin exon 9. Top, Position of primers (a through d) relative to intron 8 and exon 9 and position of mutation (denoted by ) found in affected and carrier members of XLCM-1. Bottom, Sequences of primers a through d and expected PCR products. Primers a/d were used to PCR-amplify normal exon 9 sequences; primers a/c were used to amplify mutated exon 9 sequences. Primers a/d were used for SSCP analysis. B, PCR analysis of eight members of XLCM-1 family. XLCM-1 family members analyzed (top) and resultant PCR products (bottom) are shown. With primers (a/b) designed to amplify normal dystrophin exon 9 sequence (top band) and primers (a/c) designed to amplify mutated sequence (lower band), PCR products were electrophoresed on a 2% agarose gel. Note that affected males amplify only mutated sequences; carrier females are heterozygous. All members of this family were evaluated with both primer pairs (data not shown), with expected results (based on clinical status) occurring in all cases. Genomic DNA was used as template for this experiment.

Sequencing. Normal and aberrant SSCP conformers were cut directly from dried gels and eluted in 100 µL distilled water (65°C for 30 minutes), and the eluted DNA (10 µL) was used as the template in a second PCR using the original primer pair. The PCR products were sequenced directly after fractionation in 2% low-melting agarose gel (FMC Corp) and purified by Qiaquick columns (Qiagen). Purified PCR products (200 ng) were used for each sequencing reaction with cycle sequencing.⁴³ Alternatively, purified PCR products were cloned into pBluescript 11 SK(+) (Stratagene) by the T-vector method as described previously.⁴⁴ Manual sequencing was performed according to conditions suggested by the supplier (United States Biochemical), and automated sequences were performed on an ABI Automated Sequencer (ABI model 373).

Protein modeling. Dystrophin sequences were analyzed for species conservation by use of GenBank. Analysis of amino acid sequences was performed by the MOSAIC computer program.^{45 46} Hydrophobicity and plot structure predictions were performed according to the Garnier-Osguthorpe-Robson prediction method.⁴⁷

	Results

Top Abstract Introduction Methods Results Discussion References

 
Phenotypic Analysis of XLCM Families
To identify the disease-causing mutations in XLCM, three previously described multigenerational families with familial DCM, X-linked inheritance, and no clinical evidence of skeletal disease were studied.^{8 9 10} These families were not related, and all were of North American descent. Two of the families were black (XLCM-1, XLCM-3) and one family was white (XLCM-2). All three families were previously found to have linkage to the 5' portion of the dystrophin gene at Xp21, with maximal logarithm-of-the-odds scores at intron 7 within DXS206.^{9 10}

PCR Amplification of Promoter-Specific Transcripts
With oligonucleotide primers designed to amplify sequences of the P_B,¹³ P_M,^{16 29} P_P,¹⁷ and E1-I1^{11 29 37} from DNA and RNA isolated from lymphoblastoid cell lines and cardiac tissue, normal amplification of all promoters and E1-I1 was seen in all individuals. DNA sequencing revealed normal sequences of all amplified products.

5' Dystrophin Mutation Analysis
Primers designed to individually amplify exons 2 through 14 of dystrophin¹¹ were used to analyze the region with tightest linkage in XLCM-1, XLCM-2, and XLCM-3. In XLCM-2 and XLCM-3, all exons were able to be amplified, and the resultant amplimers were the predicted sizes. SSCP analysis was also normal (ie, no abnormal conformers) in XLCM-2 and XLCM-3, as were the sequences of all amplimers. In XLCM-1, however, exon 9 could not be amplified with normal sequence primers (ie, primers a/b). SSCP analysis of affected and carrier individuals from XLCM-1 demonstrated an abnormal conformer at exon 9 in all affected individuals (hemizygous); a heterozygous result (an abnormal conformer and a normal conformer) was found in all carrier females (Fig 2). Evaluation of exon 9 sequence (GenBank reference No. X14298) identified a mutation at nucleotide 1043, with substitution of AG only in affected and carrier individuals (Fig 3). The AG mutation changes the conserved amino acid threonine at amino acid position 279 to alanine (T279A). This amino acid, which is within the H1 of dystrophin,^{48 49} is conserved across species^{50 51 52 53 54} (Table). Oligonucleotide primers containing the mutated sequence within the primers (primers a/c, Fig 1A) were able to amplify a PCR product in affected and carrier XLCM-1 patients but not in unaffected individuals (Fig 1B), whereas PCR primers designed to the normal sequence (primers a/b, Fig 1A) were able to amplify the normal exon 9 sequence in unaffected individuals but were unable to amplify this portion of exon 9 in affected patients in XLCM-1 (Fig 1B). This selective amplification of the mutated sequence in affected individuals by use of mutation-specific primers occurred because of the use of stringent PCR conditions and sequence-specific oligonucleotides. Multiplex PCR^{40 41} using 6 primer pairs (P_M, exon 9, exon 13, exon 43, exon 50, exon 52) and 10 primer pairs (exon 4, exon 8, exon 9, exon 12, exon 17, exon 19, exon 44, exon 45, exon 48, exon 51) identified the mutation in all affected and carrier individuals from XLCM-1 at exon 9. Primers designed to flank the mutated region amplified appropriately in all individuals; sequence analysis in the affected patients in pedigree XLCM-1 identified this same mutation. Hence, the missense mutation segregates with disease status within family XLCM-1. No other individuals in XLCM-1, XLCM-2, or XLCM-3 had the AG mutation at nucleotide 1043; none of 100 unrelated control individuals analyzed had the mutation as seen by PCR, SSCP, and mutation analysis. However, a GA polymorphism in the third nucleotide of this codon was commonly detected at nucleotide 1045, consistent with codon redundancy (degenerate code). In fact, the GA polymorphism at 1045 was seen in 8% of individuals in the three families as well as in 8% of the 100 unrelated normal control patients analyzed.

View larger version (38K): [in this window] [in a new window]   Figure 2. SSCP analysis of dystrophin exon 9 in genomic DNA from normal male and female individuals and individuals from XLCM-1 (proband) and XLCM-3 (mother and proband) with primers a through d. In XLCM-1 (lane 3), note aberrant conformer (ie, "mutation") that differs from normal and polymorphic bands seen in normal individuals (lanes 1 and 2) and XLCM-3 patients (lanes 4 and 5). All XLCM-1 affected and carrier individuals were found to have "mutation"; none of 100 normal control subjects or XLCM-2 or XLCM-3 patients had this abnormal conformer.

View larger version (89K): [in this window] [in a new window]   Figure 3. Manual (A) and automated (B) sequencing of normal, polymorphic, and mutated conformers obtained by SSCP. Mutated sequence AG at nucleotide 1043, which occurred in proband and all affected and carrier individuals from XLCM-1, changes conserved amino acid threonine (at position 279) to alanine. Polymorphism seen in normal population and XLCM-2 and XLCM-3 patients is also shown.

View this table: [in this window] [in a new window]   Table 1.

Dystrophin Protein Analysis
Analysis of amino acid sequences was performed by the MOSAIC computer program^{45 46} ; prediction of -helix and ß-sheet was performed by a segment-oriented method designed to locate secondary structure elements. In addition, hydrophobicity and plot structure predictions were performed by use of the Garnier-Osguthorpe-Robson prediction.⁴⁷ The T279A amino acid substitution induces a change in the polarity in this critical region of the dystrophin protein because threonine is a neutral-polar amino acid and alanine is neutral-nonpolar. This, in turn, changes the secondary and tertiary structure of dystrophin by substituting a ß-sheet for -helix at the H1 between the N-terminal domain and rod domain of dystrophin^{49 55} (Fig 4).

View larger version (38K): [in this window] [in a new window]   Figure 4. Plot structure prediction of mutant dystrophin protein compared with normal dystrophin. A, Normal dystrophin protein and mutant dystrophin (inset). Note structural change between amino acids 250 and 300 (arrow), thus causing a change in secondary structure. B, Idealized dystrophin protein structure. Change in structure due to T279A mutation at H1 is shown. This change is predicted to functionally destabilize the protein.

	Discussion

Top Abstract Introduction Methods Results Discussion References

 
XLCM is the result of mutations within the dystrophin gene at the Xp21 locus. The missense mutation in dystrophin reported here in the originally described family with XLCM initially described by Berko and Swift⁸ is found within exon 9 (AG at position 1043) and is within a critical structural region (H1) of this cytoskeletal protein.^{19 47 48 49 55 56} The resultant amino acid substitution (threoninealanine) at amino acid 279 is within a highly conserved portion of the protein,^{50 51 52 53 54} causing a change in polarity in this part of the protein and leading to a change in the dystrophin secondary and tertiary structure. The end result is conversion of a segment of -helix to a ß-sheet in the H1 between the N-terminal domain and the rod domain of dystrophin⁴⁹ ; this abnormality could potentially destabilize the protein. This mutation was not found in the other two XLCM families (XLCM-2, XLCM-3) studied.

Dystrophin is predicted to fold into four domains,^{19 49 56} including the N-terminal domain, a long repeat domain (rod domain), a cysteine-rich domain, and a C-terminal domain. The N-terminal domain has significant similarity to the N-terminal domain of -actinin and ß-spectrin,^{57 58} possibly reflecting a common actin-binding function. The large midportion of the protein is formed by repeat elements predicted to adopt a triple-helical conformation,⁵⁹ and this region is quite similar to that seen in -actinin and spectrin as well. In dystrophin, this repeat domain is composed of 24 repeat units (109 amino acid repeats) and shows evolutionary conservation.⁶⁰ In addition, Koenig and Kunkel⁴⁹ showed that four hinge segments are interspersed along the dystrophin molecule, and these hinges appear to confer flexibility to the membrane-associated network of dystrophin, resulting in membrane resilience. The existence of these flexible hinges at precise positions within the elongated dystrophin molecule is thought to be important for the mechanical properties of the membrane cytoskeleton. It is possible that flexibility is needed during contraction-relaxation of the muscle fibers. These hinge regions are found at positions within the protein encoded by exon 9 and part of exon 8 (hinge 1, amino acid 253 to 327), exon 17 (hinge 2, amino acid 667 to 717), and exon 50 to 51 (hinge 3, amino acid 2424 to 2470); the hinge 4 sequence (amino acid 3041 to 3112) has not been definitively identified.⁴⁹ The mutation identified in family XLCM-1 is in exon 9, within the H1.

It appears that dystrophin performs a number of distinct cytoskeletal functions. Three related but conceptually distinct roles of dystrophin function have been suggested: (1) membrane stability (dystrophin may stabilize the membrane during repeated cycles of muscle contraction), (2) force transduction (dystrophin may link the contractile force produced in the intracellular domain to the extracellular environment), and (3) organization of membrane specializations. The biochemistry and function of the cardiac membrane and T tubules appear to be different from those of skeletal muscle. In the heart, this exon 9 mutation affecting the H1 portion of the protein is likely to result in loss of membrane integrity and eventual loss of function, probably due to the continual stress placed on the beating pump. In addition, this portion of the protein has been shown to have significant sequence similarity to troponin I⁶¹ in the region that functionally enables binding with calcium binding proteins. It has also been speculated that dystrophin binds to calmodulin in this region, thereby modulating interaction of dystrophin with actin or other proteins associated with the cytoskeleton. It is possible that disruption of this region of dystrophin leads to the development of dilated cardiomyopathy, in part because of the inability of the mutated protein to modulate this interaction. Conversely, skeletal muscle appears to maintain normal clinical function significantly longer in XLCM patients, with the only evidence of skeletal disease being elevated serum CK-MM.

The mutation identified in family XLCM-1 reported here differs from the P_M-E1 deletion mutation reported by Muntoni et al²⁹ and the E1-I1 splice site mutation reported by Milasin et al.³⁷ Because two other families with XLCM (XLCM-2, XLCM-3) that were also analyzed for the P_M mutation, E1-I1 boundary mutation, and exon 9 mutation have normal sequences in these portions of the dystrophin gene, one can speculate that the XLCM phenotype results from multiple different dystrophin mutations that are within important functional regions of this huge protein. This possibility provides a different mechanism for the development of differential dystrophinopathic phenotypes than does the "frame-shift" hypothesis,^{62 63} which is believed to explain the phenotypic differences between the allelic diseases DMD and BMD when deletions occur in >95% of cases.

Mutations and polymorphisms in exon 9 have rarely been reported.^{64 65 66 67 68} Roberts et al⁶⁵ analyzed 70 small mutations and Prior et al⁶⁶ reviewed 29 mutations, and in no case was exon 9 mutated. Reiss and Rininsland⁶⁴ described a constitutive exon 9 cassette-splicing phenomenon found in peripheral blood lymphocyte studies. These authors found that in approximately half of the transcripts of the dystrophin gene isolated from lymphocytes, exon 9 was omitted. This exon skipping was found to occur to a variable extent in all tissues not specifically expressing dystrophin but was rarely seen in muscle, heart, or brain. When seen, omission of exon 9 did not disrupt the reading frame of the mRNA. They also suggested that when exon 9 mutations occur, BMD results (as long as the correct reading frame is maintained), consistent with the observations of Koenig et al.⁶³

Once the mutations are identified in other families with XLCM (ie, XLCM-2 and XLCM-3), more insight will be gained as to the important cardiac functional regions of dystrophin. Animal models (such as transgenic mice) with these "cardiospecific mutations" could open doors to our knowledge of the function of the dystrophin protein as well as its relationship to other interrelated proteins.

	Selected Abbreviations and Acronyms

 

BMD = Becker muscular dystrophy C-terminal = carboxy-terminal CK-MM = creatine kinase muscle isoforms DCM = dilated cardiomyopathy DMD = Duchenne muscular dystrophy E1 = exon 1 H1 = first hinge region I1 = intron 1 N-terminal = amino-terminal PB = brain promoter PCR = polymerase chain reaction PM = muscle promoter PP = Purkinje-cell promoter RT = reverse-transcriptase SSCP = single-strand conformation polymorphism XLCM = X-linked dilated cardiomyopathy

	Acknowledgments

 
This work was supported in part by the National Institutes of Health (K08-HL-02485-01 and R01-HL-53392-01) and was performed in the Phoebe Willingham Muzzy Pediatric Molecular Cardiology Laboratory. The authors wish to acknowledge the contribution of Valerie R. Price in the preparation of this manuscript.

	Footnotes

 
Reprint requests to Jeffrey A. Towbin, MD, Pediatric Cardiology, Baylor College of Medicine, One Baylor Plaza, Room 333E, Houston, TX 77030.

Guest editor for this article was Christine Seidman, MD, Harvard Medical School, Boston, Mass.

Received June 3, 1996; revision received November 12, 1996; accepted December 13, 1996.

	References

Top Abstract Introduction Methods Results Discussion References

 
1. Dec GW, Fuster V. Idiopathic dilated cardiomyopathy. N Engl J Med. 1994;331:1564-1575.[Free Full Text]

2. Manolio TA, Baughman KL, Rodeheffer R, Pearson TA, Bristow JD, Michels VV, Abelmann WH, Harlan WR. Prevalence and etiology of idiopathic dilated cardiomyopathy (summary of a National Heart, Lung, and Blood Institute workshop). Am J Cardiol. 1992;17:1458-1466.

3. Evans RW. Measuring the costs of heart transplantation. Primary Cardiol. 1994;20:48-54.

4. Michels VV, Moll PP, Miller FA, Tajik AJ, Chu JS, Driscoll DJ, Burnett JC, Rodeheffer RJ, Chesebro JH, Tazelaar HD. The frequency of familial dilated cardiomyopathy in a series of patients with idiopathic dilated cardiomyopathy. N Engl J Med. 1992;326:77-82.[Abstract]

5. Keeling PJ, Gang Y, Smith G, Seo H, Bent SE, Murday V, Caforio AL, McKenna WJ. Familial dilated cardiomyopathy in the United Kingdom. Br Heart J. 1995;73:417-421.[Abstract/Free Full Text]

6. Towbin JA. Molecular genetic aspects of cardiomyopathy. Biochem Med Metab Biol. 1993;49:285-320.[Medline] [Order article via Infotrieve]

7. Emanuel R, Withers R, O'Brien K. Dominant and recessive modes of inheritance in idiopathic cardiomyopathy. Lancet. 1971;2:1065-1067.[Medline] [Order article via Infotrieve]

8. Berko BA, Swift M. X-linked dilated cardiomyopathy. N Engl J Med. 1987;316:1186-1191.[Abstract]

9. Towbin JA, Hejtmancik JF, Brink P, Belb B, Zhu XM, Chamberlain JS, McCabe ER, Swift M. X-linked dilated cardiomyopathy: molecular genetic evidence of linkage to the Duchenne muscular dystrophy (dystrophin) gene at the Xp21 locus. Circulation. 1993;87:1854-1865.[Abstract/Free Full Text]

10. Towbin JA. Biochemical and molecular characterization of X-linked dilated cardiomyopathy (XLCM). In: Clark EB, Markwald RR, Takao A, eds. Developmental Mechanisms of Heart Disease. Armonk, NY: Futura Publishing Co Inc; 1995:121-132.

11. Koenig M, Hoffman EP, Bertelson CJ, Monaco AP, Feener C, Kunkel LM. Complete cloning of the Duchenne muscular dystrophy (DMD) cDNA and preliminary genomic organization of the DMD gene in normal and affected individuals. Cell. 1987;50:509-517.[Medline] [Order article via Infotrieve]

12. Hoffman EP, Brown RH, Kunkel LM. The protein product of the Duchenne muscular dystrophy locus. Cell. 1987;51:919-928.[Medline] [Order article via Infotrieve]

13. Boyce FM, Beggs AH, Feener C, Kunkel LM. Dystrophin is transcribed in brain from a distant upstream promoter. Proc Natl Acad Sci U S A. 1991;88:1276-1280.[Abstract/Free Full Text]

14. Feener CA, Koenig M, Kunkel LM. Alternative splicing of human dystrophin mRNA generates isoforms at the carboxy terminus. Nature. 1989;338:509-511.[Medline] [Order article via Infotrieve]

15. Nudel U, Zuk D, Einat P, Zeelon E, Levy Z, Neuman S, Yaffe D. Duchenne muscular dystrophy gene product is not identical in muscle and brain. Nature. 1989;337:76-78.[Medline] [Order article via Infotrieve]

16. Klamut HJ, Gangopadhyay SB, Worton RG, Ray PN. Molecular and functional analysis of the muscle specific promoter region of the Duchenne muscular dystrophy gene. Mol Cell Biol. 1990;10:193-205.[Abstract/Free Full Text]

17. Gorecki DC, Monaco AP, Derry JMJ, Walker AP, Barnard EA, Barnard PJ. Expression of four alternative dystrophin transcripts in brain regions regulated by different promoters. Hum Mol Genet. 1992;1:505-510.[Abstract/Free Full Text]

18. Nishio H, Takeshima Y, Narita N, Yanagawa H, Suzuki Y, Ishikawa Y, Ishikawa Y, Minami R, Nakamura H, Matsuo M. Identification of a novel first exon in the human dystrophin gene and of a new promoter located more than 500 kb upstream of the nearest known promoter. J Clin Invest. 1994;94:1037-1042.

19. Koenig M, Monaco AP, Kunkel LM. The complete sequence of dystrophin predicts a rod-shaped cytoskeletal protein. Cell. 1988;53:219-228.[Medline] [Order article via Infotrieve]

20. Klietsch R, Ervasti JM, Arnold W, Campbell KP, Jorgensen AO. Dystrophin-glycoprotein complex and lamina colocalize to the sarcolemma and transverse tubules of cardiac muscle. Circ Res. 1993;72:349-360.[Abstract/Free Full Text]

21. Campbell KP, Kahl SD. Association of dystrophy and an integral membrane glycoprotein. Nature. 1989;338:259-262.[Medline] [Order article via Infotrieve]

22. Ervasti JM, Campbell KP. Membrane organization of the dystrophin-glycoprotein complex. Cell. 1991;66:1121-1131.[Medline] [Order article via Infotrieve]

23. Michalak M, Zubrzycka-Gaarn EE. Identification of dystrophin in cardiac sarcolemmal vesicles. Biochem Biophys Res Commun. 1990;169:565-570.[Medline] [Order article via Infotrieve]

24. Yoshida M, Ozawa E. Glycoprotein complex anchoring dystrophin to sarcolemma. J Biochem. 1990;108:748-752.[Abstract/Free Full Text]

25. Ibraghimov-Beskrovnaya O, Ervasti JM, Leveille CJ, Slaughter CA, Sernett SW, Campbell KP. Primary structure of dystrophin-associated glycoproteins linking dystrophin to the extracellular matrix. Nature. 1992;355:696-702.[Medline] [Order article via Infotrieve]

26. Matsumura K, Nonaka I, Tome FM, Arahata K, Collin H, Leturcq F, Recan D, Kaplan JC, Fardeau M, Campbell KP. Mild deficiency of dystrophin-associated proteins in Becker muscular dystrophy patients having in-frame deletions in the rod domain of dystrophin. Am J Hum Genet. 1993;53:409-416.[Medline] [Order article via Infotrieve]

27. Ohlendieck K, Matsumura K, Ionasescu VV, Towbin JA, Bosch EP, Weinstein SL, Sernett SW, Campbell KP. Duchenne muscular dystrophy: deficiency of the dystrophin-associated proteins in the sarcolemma. Neurology. 1993;43:795-800.[Abstract/Free Full Text]

28. Tinsley JM, Blake DJ, Zuellig RA, Davies KE. Increasing complexity of the dystrophin-associated protein complex. Proc Natl Acad Sci U S A. 1994;91:8307-8313.[Abstract/Free Full Text]

29. Muntoni F, Cau M, Ganau A, Congiu R, Arvedi G, Mateddu A, Marrosu MG, Cianchetti C, Realdi G, Cao A, Melis MA. Brief report: deletion of the dystrophin muscle-promoter region associated with X-linked dilated cardiomyopathy. N Engl J Med. 1993;329:921-925.[Free Full Text]

30. Muntoni F, Melis MA, Ganau A, Dubowitz V. Transcription of the dystrophin gene in normal tissues and in skeletal muscle of a family with X-linked dilated cardiomyopathy. Am J Hum Genet. 1995;56:151-157.[Medline] [Order article via Infotrieve]

31. Muntoni F, Melis MA, Ganau A, Dubowitz V. A mutation in the dystrophin gene selectively affecting dystrophin expression in the heart. J Clin Invest. 1995;96:693-699.

32. Holder E, Maeda M, Bies RD. Expression and regulation of the dystrophin Purkinje promoter in human skeletal muscle, heart, and brain. Hum Genet. 1996;97:232-239.[Medline] [Order article via Infotrieve]

33. Vitiello L, Mostacciuolo ML, Oliviero S, Schiavon F, Nicoletti L, Angelini C, Danieli GA. Screening for mutations in the muscle promoter region and for exonic deletions in a series of 115 DMD and BMD patients. J Med Genet. 1992;29:127-130.[Abstract/Free Full Text]

34. Beggs AH, Hoffman EP, Snyder JR, Arahata K, Specht L, Shapiro F, Angelini C, Sugita H, Kunkel LM. Exploring the molecular basis for variability among patients with Becker muscular dystrophy: dystrophin gene and protein studies. Am J Hum Genet. 1991;49:54-67.[Medline] [Order article via Infotrieve]

35. Yoshida K, Ikeda S, Nakamura A, Kagoshima M, Takeda S, Shoji S, Yanagisawa N. Molecular analysis of the Duchenne muscular dystrophy gene in patients with Becker muscular dystrophy presenting with dilated cardiomyopathy. Muscles Nerve. 1993;16:1161-1166.

36. Towbin JA, Ortiz-Lopez R. X-linked dilated cardiomyopathy is not due to a muscular promoter deletion in dystrophin in three families. N Engl J Med. 1994;330:369-370.

37. Milasin J, Muntoni F, Severini GM, Bartoloni L, Vatta M, Krajinovic M, Mateddu A, Angelini C, Camerini F, Falaschi A, Mestroni L, Giacca M, and HMD Study Group. A point mutation in the 5' splice site of the dystrophin gene first intron responsible for X-linked dilated cardiomyopathy. Hum Mol Genet. 1996;5:73-79.[Abstract/Free Full Text]

38. Miller G, Lisco H, Stitt D. Establishment of cell lines from normal adult human blood leukocytes by exposure to Epstein-Barr virus and neutralization by human sera with Epstein-Barr virus antibody. Proc Soc Exp Biol Med. 1971;137:1459-1465.[Medline] [Order article via Infotrieve]

39. Roberts RG, Darby TFM, Manners E, Bobrow M, Bentley DR. Direct detection of dystrophin gene rearrangements by analysis of dystrophin mRNA in peripheral blood lymphocytes. Am J Hum Genet. 1991;49:298-310.[Medline] [Order article via Infotrieve]

40. Beggs AH, Koenig M, Boyce FM, Kunkel LM. Deletion of 98% of DMD/BMD gene deletions by polymerase chain reaction. Hum Genet. 1990;86:45-48.[Medline] [Order article via Infotrieve]

41. Chamberlain JS, Gibbs RA, Ranier JE, Nguyen PN, Caskey CT. Deletion screening of the Duchenne muscular dystrophy locus via multiplex DNA amplification. Nucleic Acids Res. 1988;23:11141-11156.

42. Orita M, Suzuki Y, Sekiya T, Hayashi K. Rapid and sensitive detection of point mutations and DNA polymorphisms using the polymerase chain reaction. Genomics. 1989;5:874-879.[Medline] [Order article via Infotrieve]

43. Wang Q, Keating MT. Isolation of P1 inserts ends by direct sequencing. Biotechniques. 1994;17:282-284.[Medline] [Order article via Infotrieve]

44. Marchuk D, Drumm M, Saulino A, Collins FS. Construction of T-vectors, a rapid and general system for direct cloning of unmodified PCR products. Nucleic Acids Res. 1990;19:1154.[Free Full Text]

45. Solovyev VV, Salamov AA. Secondary structure prediction based on discriminant analysis. In: Kolchanov NA, Lim HA, eds. Computer Analysis of Genetic Macromolecules. World Scientific; 1994:352-364.

46. Solovyev VV, Salamov AA. Predicting -helix and ß-strand segments of globular proteins. Comput Appl Biosci. 1994;10:661-669.[Abstract/Free Full Text]

47. Garnier J, Osguthorpe DJ, Robson B. Analysis of the accuracy and implications of simple methods for predicting the secondary structure of globular proteins. J Mol Biol. 1978;120:97-120.[Medline] [Order article via Infotrieve]

48. Roberts RG, Coffey A, Bobrow M, Bentley DR. Exon structure of the human dystrophin gene. Genomics. 1993;16:536-538.[Medline] [Order article via Infotrieve]

49. Koenig M, Kunkel LM. Detailed analysis of the repeat domain of dystrophin reveals four potential hinge segments that may confer flexibility. J Biol Chem. 1990;265:4560-4566.[Abstract/Free Full Text]

50. Lemaire C, Helig R, Mandel JL. Nucleotide sequence of chicken dystrophin cDNA. Nucleic Acids Res. 1988;16:11815-11816.[Free Full Text]

51. Chang HW, Bock E, Bonilla E. Dystrophin in electric organ of Torpedo californica homologous to that in human muscle. J Biol Chem. 1989;263:20831-20834.

52. Byers TJ, Husain-Chishti A, Dubreuil RR, Branton D, Goldstein LSB. Sequence similarity of the amino-terminal domain of Drosophila beta spectrin to alpha actinin and dystrophin. J Cell Biol. 1989;109:1633-1641.[Abstract/Free Full Text]

53. Bartlett RJ, Sharp NJH, Secore SL, Hung WY, Kornegay JN, Roses AD. The canine and human DYS genes are highly conserved. J Neurol Sci. 1990;98(suppl):165. Abstract.

54. Ryder-Cook AS, Sicinski P, Thomas K, Davies KE, Worton RG, Barnard EA, Darlison MG, Barnard PJ. Localization of the mdx mutation within the mouse dystrophin gene. EMBO J. 1988;7:3017-3021.[Medline] [Order article via Infotrieve]

55. Kahana E, Marsh PJ, Henry AJ, Way M, Gratzer WB. Conformation and phasing of dystrophin structural repeats. J Mol Biol. 1994;235:1271-1277.[Medline] [Order article via Infotrieve]

56. Ahn AH, Kunkel LM. The structural and functional diversity of dystrophin. Nat Genet. 1993;3:283-291.[Medline] [Order article via Infotrieve]

57. Hammonds RG Jr. Protein sequence of DMD gene is related to actin-binding domain of alpha-actinin. Cell. 1987;51:1. Letter.[Medline] [Order article via Infotrieve]

58. Davidson MD, Baron MD, Critchley DR, Wootton JC. Structural analysis of homologous repeated domains in alpha-actinin and spectrin. Int J Biol Macromol. 1989;11:81-90.[Medline] [Order article via Infotrieve]

59. Speicher DW, Marchesi VT. Erythrocyte spectrin is comprised of many homologous triple helical segments. Nature. 1984;311:177-180.[Medline] [Order article via Infotrieve]

60. Sherratt TG, Vulliamy T, Strong PN. Evolutionary conservation of the dystrophin central rod domain. Biochem J. 1992;287:755-759.

61. Gurusinghe AD, Wilce MCJ, Austin L, Hearn MTW. Duchenne muscular dystrophy and dystrophin: sequence homology observations. Neurochem Res. 1991;16:681-686.[Medline] [Order article via Infotrieve]

62. Malhotra SB, Hart KA, Klamut HJ, Thomas NS, Bodrug SE, Burghes AH, Bobrow M, Harper PS, Thompson MW, Ray PN, Worton RG. Frame-shift deletions in patients with Duchenne and Becker muscular dystrophy. Science. 1988;242:755-759.[Abstract/Free Full Text]

63. Koenig M, Beggs AH, Moyer M, Scherpf S, Heindrich K, Bettecken T, Meng G, Muller CR, Lindlof M, Kaariainen H, de la Chapelle A, Kiuru A, Savontaus ML, Gilgenkrants H, Recan D, Chelly J, Kaplan JC, Covone AE, Archidiacono N, Romeo G, Liechti-Gallati S, Schneider V, Braga S, Moser H, Darras BT, Murphy P, Francke U, Chen JD, Morgan G, Denton M, Greenberg CR, Van Ommen GJB, Kunkel LM. The molecular basis for Duchenne versus Becker muscular dystrophy: correlation of severity with type of deletion. Am J Hum Genet. 1989;45:498-506.[Medline] [Order article via Infotrieve]

64. Reiss J, Rininsland F. An explanation for the constitutive exon 9 cassette splicing of the DMD gene. Hum Mol Genet. 1994;3:295-298.[Abstract/Free Full Text]

65. Roberts RG, Gardner RJ, Bobrow M. Searching for the 1 in 2,400,000: a review of dystrophin gene point mutations. Hum Mutat. 1994;4:1-11.[Medline] [Order article via Infotrieve]

66. Prior TW, Bartolo C, Pearl DK, Papp AC, Snyder PJ, Sedra MS, Burghes AHM, Mendell JR. Spectrum of small mutations in the dystrophin coding region. Am J Hum Genet. 1995;57:22-33.[Medline] [Order article via Infotrieve]

67. Grimm T, Meng G, Liechti-Gallati S, Bettecken T, Muller CR, Muller B. On the origin of deletions and point mutations in Duchenne muscular dystrophy: most deletions arise in oogenesis and most point mutations result from events in spermatogenesis. J Med Genet. 1994;31:183-186.[Abstract/Free Full Text]

68. Kilimann MW, Pizzuti A, Grompe M, Caskey CT. Point mutations and polymorphisms in the human dystrophin gene identified in genomic DNA sequences amplified by multiplex PCR. Hum Genet. 1992;89:253-258.[Medline] [Order article via Infotrieve]

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