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Abnormal brain MRI signal in 18q-syndrome not due to dysmyelination

Authors :
Ryuta Tanaka
Nobuaki Iwasaki
Kenzo Hamano
Tomokazu Numano
Tatsuyuki Ohto
Kazuhiro Homma
Junko Nakayama
Ryo Sumazaki
Masaharu Hayashi
Miho Takahashi
Source :
Brain and Development. 34:234-237
Publication Year :
2012
Publisher :
Elsevier BV, 2012.

Abstract

Background 18q-Syndrome is a chromosomal disorder exhibiting various symptoms arising from the central nervous system. Brain magnetic resonance imaging (MRI) of patients with this syndrome usually demonstrates abnormal white matter intensities. This is widely believed to be due to impaired myelin formation because this syndrome involves the deletion of the myelin basic protein (MBP) gene in 18q23. However, this hypothesis has not been confirmed by actual pathology because early death is unusual and autopsy rarely performed. Patient A 6-year-old boy with ring chromosome 18 syndrome was examined by genetic analysis for the MBP gene, brain MRI, and autopsy. Results Haploinsufficiency of the MBP gene was confirmed. T2-weighted MRI revealed diffuse high intensities throughout the cerebral white matter. Pathological examination showed the cerebral white matter to be uniformly stained by Kluver–Barrera and MBP immunohistochemical staining. Oligodendrocytes were immunoreactive for proteolipid protein and ferritin but not MBP. Electron microscopy revealed clusters of axons wrapped in compact myelin sheaths with distinct major dense lines. Holzer and immunohistochemical staining for glial fibrillary acidic protein showed extensive staining of the white matter and an increased number of glial filaments. Conclusions This pathological study demonstrated that in this disorder, the brain was well myelinated, contrary to established hypotheses about this disorder. The MRI signal abnormalities in 18q-syndrome could be attributed to gliosis and not to dysmyelination.

Details

ISSN :
03877604
Volume :
34
Database :
OpenAIRE
Journal :
Brain and Development
Accession number :
edsair.doi.dedup.....d4d739e88bd4338e91bec40ffe23258b
Full Text :
https://doi.org/10.1016/j.braindev.2011.05.008