Functional analysis of RRAS2 pathogenic variants with a Noonan-like phenotype

Introduction: RRAS2, a member of the R-Ras subfamily of Ras-like low-molecular-weight GTPases, is considered to regulate cell proliferation and differentiation via the RAS/MAPK signaling pathway. Seven RRAS2 pathogenic variants have been reported in patients with Noonan syndrome; however, few functional analyses have been conducted. Herein, we report two patients who presented with a Noonan-like phenotype with recurrent and novel RRAS2 pathogenic variants (p.Gly23Val and p.Gly24Glu, respectively) and the results of their functional analysis.Materials and methods: Wild-type (WT) and mutant RRAS2 genes were transiently expressed in Human Embryonic Kidney293 cells. Expression of RRAS2 and phosphorylation of ERK1/2 were confirmed by Western blotting, and the RAS signaling pathway activity was measured using a reporter assay system with the serum response element-luciferase construct. WT and p.Gly23Val RRAS2 were expressed in Drosophila eye using the glass multiple reporter-Gal4 driver. Mutant mRNA microinjection into zebrafish embryos was performed, and the embryo jaws were observed.Results: No obvious differences in the expression of proteins WT, p.Gly23Val, and p.Gly24Glu were observed. The luciferase reporter assay showed that the activity of p.Gly23Val was 2.45 ± 0.95-fold higher than WT, and p.Gly24Glu was 3.06 ± 1.35-fold higher than WT. For transgenic flies, the p.Gly23Val expression resulted in no adults flies emerging, indicating lethality. For mutant mRNA-injected zebrafish embryos, an oval shape and delayed jaw development were observed compared with WT mRNA-injected embryos. These indicated hyperactivity of the RAS signaling pathway.Discussion: Recurrent and novel RRAS2 variants that we reported showed increased in vitro or in vivo RAS signaling pathway activity because of gain-of-function RRAS2 variants. Clinical features are similar to those previously reported, suggesting that RRAS2 gain-of-function variants cause this disease in patients

ＩＣＴ教育導入における視力低下の実態と効果的な健康管理について

In recent years, the incidence of myopia in children has been increasing, so it is important to determine the effects of environmental and lifestyle factors at an early stage and take countermeasures. The purpose of this study was to examine in detail the changes in the use of electronic devices and the changes in the visual acuity of children Comparing the good vision group and the poor vision group, no significant differences were observed in the frequency of attending cram schools, the frequency of exercising outside, the amount of time spent using electronic devices, and sleep. Although no significant difference was observed in stress response, the poor visual acuity group had a higher physical reaction score, and symptoms such as headache and fatigue we re observed compared to the good visual acuity group. Children's use of electronic devices was predicted to be longer than before COVID 19, but no significant change was observed in this study. It is believed that he lived under the supervision of his parents. In the future, it is necessary to investigate parents' ideas and measures to maintain their eyesight, clarify the relationship with children's eyesight, and consider guidance not only for children but also for parents