Development of cardiomyopathy in female carriers of Duchenne and Becker muscular dystrophies.
OBJECTIVE
To characterize the presence and behavior of the dystrophinopathic myocardial damage in female carriers of a gene defect at the Xp21 locus of the X chromosome that causes Duchenne and Becker muscular dystrophies (DMD and BMD).


METHODS
Cohort study from April 1, 1985, to April 30, 1995, with cardiologic follow-up performed yearly for a minimum of 3 to a maximum of 10 years.


METHODS
Counseling center for genetic muscular disorders.


METHODS
A total of 197 women and girls aged 5 to 60 years ascertained to be carriers of the DMD (n = 152) or BMD (n = 45) gene.


METHODS
Cardiac status at yearly examinations as determined by 12-lead electrocardiogram (ECG), 24-hour ambulatory ECG, M-mode and 2-dimensional echocardiography, and carotid pulse tracing. Myocardial scintigram was performed on each individual at least twice during the study. Immunohistochemical analysis of dystrophin from myocardium and/or skeletal muscle biopsy was performed in 12 carriers.


RESULTS
Preclinical or clinically evident myocardial involvement was found in 166 cases (84.3%), without significant differences in percentage and behavior between DMD and BMD carriers. Its occurrence increased significantly with age, from 54.5% (18 cases) in carriers aged between 5 and 16 years to 90.2% (148 cases) in carriers older than 16 years. Dystrophin anomalies were detected at the membrane level of the myocardial fibers in all endomyocardial biopsy specimens.


CONCLUSIONS
Genetic anomalies can be considered the primary cause of myocardial damage in carriers of dystrophinopathic myopathies; myocardial damage shows the same behavior already described in DMD and BMD patients and progresses from preclinical to dilated cardiomyopathy, passing through stages of myocardial hypertrophy or dysrhythmias.
Politano
L
L
Department of Internal and Experimental Medicine, Second Naples University, Italy.
Nigro
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V
Nigro
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Petretta
V R
VR
Passamano
L
L
Papparella
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Di Somma
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Comi
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LI
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D009202:Cardiomyopathies / Q000235:genetics* / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D016189:Dystrophin / Q000378:metabolism; D005260:Female; D006334:Heart Function Tests; D006579:Heterozygote; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology; D009136:Muscular Dystrophies / Q000235:genetics / Q000503:physiopathology*; D009206:Myocardium / Q000378:metabolism / Q000473:pathology
D016189:Dystrophin