Charcot-Marie-Tooth disease 2A (CMT2A) is the most common axonal form of peripheral neuropathy caused by a defect in the mitofusin 2 (MFN2) gene, which encodes an outer mitochondrial membrane GTPase. MFN2 mutations result in a large range of phenotypes. This study analyzed the prevalence of MFN2 mutation in Korean families with their assorted phenotypes (607 CMT families and 160 CMT2 families). Direct sequencing of the MFN2 coding exons or whole-exome sequencing has been applied to identify causative mutations. A total of 21 mutations were found in 36 CMT2 families. Comparative genotype-phenotype correlations impacting severity, onset age, and specific symptoms were assessed. Most mutations were seen in the GTPase domain (∼86%). A deletion mutation found in the transmembrane helices is reported for the first time, as well as five novel mutations at other domains. MFN2 mutations made up 5.9% of total CMT families, whereas 22.9% in CMT2 families, of which 27.8% occurred de novo. Interestingly, patient phenotypes ranged from mild to severe even for the same mutation, suggesting other factors influenced phenotype and penetrance. This CMT2A cohort study will be useful for molecular diagnosis and treatment of axonal neuropathy.

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This paper studies the characteristics of junction structure of closed-cell type aluminum foam, which is generally used as a shock absorber. TDCB specimens were designed for mode III type with thickness as a variable and performed a fatigue experiment on them by thickness. As the result, the load value of all specimens peaks under 0 to 25 cycles and decreases as the cycles increase. As the specimen thickens by 10 mm, the maximum load value is 1.2 times. When the thickness increases by 20 mm, the maximum value increases by 1.5 times. This study result can be utilized by investigating the mechanical characteristics of TDCB specimens for mode III type under fatigue loading conditions systematically and efficiently.

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