Rett syndrome: findings suggesting axonopathy and mitochondrial abnormalities.
We report the histopathologic findings of 3 sural nerve biopsies and 1 muscle biopsy from 3 patients with Rett syndrome. The 3 sural nerve biopsies demonstrated a few ultrastructural abnormalities, including the presence of many Pi-granules and mitochondrial changes in the cytoplasm of Schwann cells, occasional bands of Büngner and onion-bulb formations, and mitochondrial alterations in myelinated axons. Morphometric analysis disclosed reduction in the number of large myelinated fibers with normal densities in comparison to those of an age-matched normal control. Light microscopic examination of the biopsied muscle from a 6-year-old patient with Rett syndrome revealed the existence of many small, dark, angulated fibers with NADH-TR staining. Ultrastructural investigation of the muscle confirmed the presence of the dumbbell-shaped mitochondria. Peripheral nerve involvement and the possibility of mitochondrial abnormalities in Rett syndrome were suggested by the results.
Wakai
S
S
Department of Pediatrics, National Sanitorium Yakumo Hospital, Hokkaido, Japan.
Kameda
K
K
Ishikawa
Y
Y
Miyamoto
S
S
Nagaoka
M
M
Okabe
M
M
Minami
R
R
Tachi
N
N
D001369:Axons / Q000473:pathology / Q000648:ultrastructure; D001706:Biopsy; D002648:Child; D005260:Female; D006801:Humans; D008928:Mitochondria / Q000648:ultrastructure; D008931:Mitochondria, Muscle / Q000648:ultrastructure; D009132:Muscles / Q000473:pathology / Q000648:ultrastructure; D009413:Nerve Fibers, Myelinated / Q000473:pathology / Q000648:ultrastructure; D015518:Rett Syndrome / Q000473:pathology*; D012583:Schwann Cells / Q000648:ultrastructure; D013497:Sural Nerve / Q000473:pathology / Q000648:ultrastructure