A new congenital muscular dystrophy with mitochondrial structural abnormalities.
We report a new form of congenital muscular dystrophy (CMD) in 4 patients from three unrelated families with probable autosomal-recessive inheritance. All patients had the clinical characteristics of merosin-positive congenital muscular dystrophy, but had marked mental retardation. The disease was slowly progressive and 1 patient died from dilated cardiomyopathy at the age of 13 years. In addition to dystrophic changes with necrosis and regeneration in muscle, the most striking finding was mitochondrial depletion in the center of the sarcoplasm. Mitochondria at the periphery of fibers were markedly enlarged ("megaconial" appearance) with complicated cristae, and contained a normal amount of mitochondrial DNA by in situ hybridization. Mitochondrial enlargement may represent functional compensation for mitochondrial depletion in the central sarcoplasm, where myofibrillar degeneration occurred.
Nishino
I
I
Department of Ultrastructural Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan.
Kobayashi
O
O
Goto
Y
Y
Kurihara
M
M
Kumagai
K
K
Fujita
T
T
Hashimoto
K
K
Horai
S
S
Nonaka
I
I
D000293:Adolescent; D002311:Cardiomyopathy, Dilated / Q000150:complications; D002648:Child; D018450:Disease Progression; D003576:Electron Transport Complex IV / Q000032:analysis; D017809:Fatal Outcome; D005260:Female; D006801:Humans; D008607:Intellectual Disability / Q000150:complications; D008297:Male; D008931:Mitochondria, Muscle / Q000473:pathology* / Q000648:ultrastructure; D018485:Muscle Fibers, Skeletal / Q000473:pathology / Q000648:ultrastructure; D009129:Muscle Tonus; D018482:Muscle, Skeletal / Q000473:pathology / Q000503:physiopathology*; D009136:Muscular Dystrophies / Q000145:classification / Q000151:congenital* / Q000473:pathology*; D009246:NADH Tetrazolium Reductase / Q000032:analysis; D012519:Sarcoplasmic Reticulum / Q000473:pathology / Q000648:ultrastructure
D009246:NADH Tetrazolium Reductase; D003576:Electron Transport Complex IV