Follow-up of three patients with a large in-frame deletion of exons 45-55 in the Duchenne muscular dystrophy (DMD) gene.
We review the clinical status of skeletal involvement and cardiac function in three unrelated patients harboring an in-frame deletion of exons 45 to 55 in the DMD gene followed up for 2 to 7 years. Two younger patients diagnosed as having X-linked dilated cardiomyopathy (XLDCM) developed congestive heart failure without overt skeletal myopathy. Heart failure recurred after viral infection but responded well to diuretics and angiotensin-converting enzyme inhibitors. One older patient diagnosed with Becker muscular dystrophy showed limb-girdle muscular atrophy and weakness at the age of 50, but did not have any cardiac symptoms. Skeletal muscle involvement in each patient remained unchanged, and cardiac function did not worsen in any of the patients during the study. In a younger XLDCM patient, the amount and molecular weight of mutant dystrophin were equally slightly decreased in both skeletal and cardiac muscles. Immunostaining for dystrophin and dystrophin-associated proteins was slightly reduced in both skeletal and cardiac muscle, with no discernible difference between the two. The phenotype of this dystrophinopathy can manifest as XLDCM in younger patients; however, careful attention to cardiac management may result in a favorable prognosis.
Nakamura
Akinori
A
Department of Neurology, Shinshu University School of Medicine, Matsumoto 390-8621, Japan. anakamu@ncnp.go.jp
Yoshida
Kunihiro
K
Fukushima
Kazuhiro
K
Ueda
Hideho
H
Urasawa
Nobuyuki
N
Koyama
Jun
J
Yazaki
Yoshikazu
Y
Yazaki
Masahide
M
Sakai
Toshiaki
T
Haruta
Seiichi
S
Takeda
Shin'ichi
S
Ikeda
Shu-Ichi
S
D000328:Adult; D000368:Aged; D002311:Cardiomyopathy, Dilated / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology; D018450:Disease Progression; D016189:Dystrophin / Q000235:genetics*; D005091:Exons / Q000235:genetics; D005500:Follow-Up Studies; D017353:Gene Deletion; D005819:Genetic Markers / Q000235:genetics; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology; D009136:Muscular Dystrophies / Q000235:genetics* / Q000473:pathology / Q000503:physiopathology; D009154:Mutation / Q000235:genetics*; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D010641:Phenotype
C484258:DMD protein, human; D016189:Dystrophin; D005819:Genetic Markers