Summary

J Clin Neurosci. 2018 Dec;58:215-217. doi: 10.1016/j.jocn.2018.10.021. Epub 2018 Oct 13.

Different clinicopathological features between Japanese siblings with facioscapulohumeral muscular dystrophy 2 with a novel nonsense SMCHD1 mutation (Arg552∗).

Abstract:

Facioscapulohumeral muscular dystrophy (FSHD) 2 is caused by a combination of heterozygous structural maintenance of chromosomes flexible hinge domain containing 1 (SMCHD1) mutation plus DNA hypomethylation on D4Z4. Here we report two Japanese FSHD2 siblings (brother and sister) with a new SMCHD1 nonsense mutation (a heterogeneous c. 1654C > T substitution, leading to a stop codon Arg552∗). They showed the typical phenotype of FSHD2 such as asymmetric muscle weakness and atrophy in bilateral facial, scapular and humeral muscles, but different clinicopathological features between them. The brother and asymptomatic mother showed normal D4Z4 methylation plus the same SMCHD1 mutation, but the sister showed the SMCHD1 mutation plus D4Z4 hypomethylation, suggesting an interesting correlation of the new SMCHD1 nonsense mutation and D4Z4 hypomethylation.

日本語要旨:

D4Z4列の縮小が観察されないFSHD2は、SMCHD1の突然変異とD4Z4の低メチル化の合併を原因とする。今回我々は、未報告のSMCHD1変異c,1654C>T(p.Arg552*)を有するFSHD2の兄妹例を経験した。兄、妹ともに顔面、肩、上腕に非対称性の筋力低下・萎縮を認めたが、臨床病理学的特徴は兄妹間で異なっていた。また、兄は症状のない母親と同様にD4Z4のメチル化は正常であったのに対し、妹ではメチル化が低下していた。FSHD2におけるSMCHD1の浸透率に関しては分からない点が多く、さらなる解明が必要である。

PMID:  30327220

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