Genetic Analysis of SCN11A, SCN10A, and SCN9A in Familial Episodic Pain Syndrome (FEPS) in Japan and Proposal of Clinical Diagnostic Criteria.

Familial episodic pain syndrome (FEPS) is an early childhood onset disorder of severe episodic limb pain caused mainly by pathogenic variants of SCN11A, SCN10A, and SCN9A, which encode three voltage-gated sodium channels (VGSCs) expressed as key determinants of nociceptor excitability in primary sensory neurons. There may still be many undiagnosed patients with FEPS. A better understanding of the associated pathogenesis, epidemiology, and clinical characteristics is needed to provide appropriate diagnosis and care. For this study, nationwide recruitment of Japanese patients was conducted using provisional clinical diagnostic criteria, followed by genetic testing for SCN11A, SCN10A, and SCN9A. In the cohort of 212 recruited patients, genetic testing revealed that 64 patients (30.2%) harbored pathogenic or likely pathogenic variants of these genes, consisting of 42 (19.8%), 14 (6.60%), and 8 (3.77%) patients with variants of SCN11A, SCN10A, and SCN9A, respectively. Meanwhile, the proportions of patients meeting the tentative clinical criteria were 89.1%, 52.0%, and 54.5% among patients with pathogenic or likely pathogenic variants of each of the three genes, suggesting the validity of these clinical criteria, especially for patients with SCN11A variants. These clinical diagnostic criteria of FEPS will accelerate the recruitment of patients with underlying pathogenic variants who are unexpectedly prevalent in Japan.

Role of ABCB1 and ABCB4 in renal and biliary excretion of perfluorooctanoic acid in mice.

BACKGROUND: Perfluorooctanoic acid (PFOA) is one of the major per- and polyfluoroalkyl substances. The role of ATP-binding cassette (ABC) transporters in PFOA toxicokinetics is unknown. METHODS: In this study, two ABC transporters, ABCB1 and ABCB4, were examined in mice with single intravenous PFOA administration (3.13 µmol/kg). To identify candidate renal PFOA transporters, we used a microarray approach to evaluate changes in gene expression of various kidney transporters in Abcb4 null mice. RESULTS: Biliary PFOA concentrations were lower in Abcb4 null mice (mean ± standard deviation: 0.25 ± 0.12 µg/mL) than in wild-type mice (0.87 ± 0.02 µg/mL). Immunohistochemically, ABCB4 expression was confirmed at the apical region of hepatocytes. However, renal clearance of PFOA was higher in Abcb4 null mice than in wild-type mice. Among 642 solute carrier and ABC transporters, 5 transporters showed significant differences in expression between wild-type and Abcb4 null mice. These candidates included two major xenobiotic transporters, multidrug resistance 1 (Abcb1) and organic anion transporter 3 (Slc22a8). Abcb1 mRNA levels were higher in Abcb4 null mice than in wild-type mice in kidney. In Abcb4 null mice, Abcb1b expression was enhanced in proximal tubules immunohistochemically, while that of Slc22a8 was not. Finally, in Abcb1a/b null mice, there was a significant decrease in the renal clearance of PFOA (0.69 ± 0.21 vs 1.1 mL ± 0.37/72 h in wild-type mice). A homology search of ABCB1 showed that several amino acids are mutated in humans compared with those in rodents and monkeys. CONCLUSIONS: These findings suggest that, in the mouse, Abcb4 and Abcb1 are excretory transporters of PFOA into bile and urine, respectively.

Oxidative DNA Damage by N4-hydroxycytidine, a Metabolite of the SARS-CoV-2 Antiviral Molnupiravir.

Molnupiravir is an antiviral agent recently used for treating coronavirus disease 2019 (COVID-19). Here, we demonstrate that N4-hydroxycytidine (NHC), a molnupiravir metabolite, treated with cytidine deaminase (CDA) induced Cu(II)-mediated oxidative DNA damage in isolated DNA. A colorimetric assay revealed hydroxylamine generation from CDA-treated NHC. The site specificity of DNA damage also suggested involvement of hydroxylamine in the damage. Furthermore, Cu(I) and H2O2 play an important role in the DNA damage. We propose oxidative DNA damage via CDA-mediated metabolism as a possible mutagenic mechanism of NHC, highlighting the need for careful risk assessment of molnupiravir use in therapies for viral diseases, including COVID-19.

Knockdown of TFRC suppressed the progression of nasopharyngeal carcinoma by downregulating the PI3K/Akt/mTOR pathway.

BACKGROUND: The transferrin receptor (TfR) encoded by TFRC gene is the main cellular iron importer. TfR is highly expressed in many cancers and is expected to be a promising new target for cancer therapy; however, its role in nasopharyngeal carcinoma (NPC) remains unknown. METHODS: The TfR levels were investigated in NPC tissues and cell lines using immunohistochemistry and reverse transcription-quantitative polymerase chain reaction. Knockdown of TFRC using two siRNA to investigate the effects on intracellular iron level and biological functions, including proliferation by CKK-8 assay, colony formation, cell apoptosis and cell cycle by flow cytometry, migration and invasion, and tumor growth in vivo by nude mouse xenografts. RNA sequencing was performed to find possible mechanism after TFRC knockdown on NPC cells and further verified by western blotting. RESULTS: TfR was overexpressed in NPC cell lines and tissues. Knockdown of TFRC inhibited cell proliferation concomitant with increased apoptosis and cell cycle arrest, and it decreased intracellular iron, colony formation, migration, invasion, and epithelial-mesenchymal transition in HK1-EBV cells. Western blotting showed that TFRC knockdown suppressed the levels of the iron storage protein FTH1, anti-apoptotic marker BCL-xL, and epithelial-mesenchymal transition markers. We confirmed in vivo that TFRC knockdown also inhibited NPC tumor growth and decreased Ki67 expression in tumor tissues of nude mouse xenografts. RNA sequencing and western blotting revealed that TFRC silencing inhibited the PI3K/Akt/mTOR signaling pathway. CONCLUSIONS: These results indicated that TfR was overexpressed in NPC, and TFRC knockdown inhibited NPC progression by suppressing the PI3K/Akt/mTOR signaling pathway. Thus, TfR may serve as a novel biomarker and therapeutic target for NPC.

Chlorinated persistent organic pollutants in human breast milk in the Miyagi Prefecture disaster-affected area 1 year after the Great East Japan Earthquake of 2011.

BACKGROUND: In the Great East Japan Earthquake of 11 March 2011, an earthquake and accompanying tsunami struck the Tohoku region of northeastern Japan. Buildings collapsed and the tsunami spread waste, including hazardous materials. This study aimed to determine the concentrations of persistent organic pollutants (POPs) in the breast milk of mothers living in the disaster-affected area of Sendai 1 year after the earthquake. Temporal trends in the POPs concentrations were evaluated by comparison with previous studies. METHODS: One hundred breast milk samples were obtained from lactating mothers at a hospital in Sendai in 2012. The results were compared with those from other years to examine whether there were changes in the POPs concentrations after the earthquake. We measured polychlorinated biphenyls (PCBs) and organochlorine pesticides, such as chlordanes, using gas chromatography-mass spectrometer (GC-MS) with negative chemical ionization, and dichlorodiphenyl trichloroethane (DDT) and its metabolites using GC-MS with electron impact ionization. RESULTS: The mean total PCBs (11 congeners), total chlordane, and total DDT concentrations were 76.2 ng/g lipid, 39.8 ng/g lipid, and 73.5 ng/g lipid, respectively. For the samples collected in 2012, the concentrations of POPs in breast milk showed minimal changes compared with results from previous years for samples collected at the same hospital in Sendai. CONCLUSIONS: Our study demonstrates that 1 year after the earthquake and tsunami, the concentrations of chlorinated POPs in breast milk had not changed substantially.

GDF10 inhibits cell proliferation and epithelial-mesenchymal transition in nasopharyngeal carcinoma by the transforming growth factor-ß/Smad and NF-κB pathways.

Growth differentiation factor-10 (GDF10) belongs to a member of the transforming growth factor-ß (TGF-ß) superfamily. Dysfunction of the TGF-ß pathway can lead to carcinoma progression. Previous studies have shown that GDF10 acts as a tumor suppressor gene in some cancers. However, the molecular mechanisms of the association between GDF10 and cell functions in nasopharyngeal carcinoma (NPC) remain unclear. In this study, the expression and methylation levels of GDF10 were studied in human subjects and cell lines. Furthermore, overexpression of GDF10 was used to explore its biological function and potential mechanism in NPC cell lines. GDF10 was downregulated in NPC owing to its aberrant promoter methylation. After treatment with 5-aza-2'-deoxycytidine, the expression of GDF10 in NPC cells was reversed. We also confirmed that the overexpression of GDF10 significantly inhibited cell proliferation and tumor growth both in vitro and in vivo, respectively. Additionally, GDF10 overexpression in NPC cells attenuated migration and invasion and inhibited epithelial-to-mesenchymal transition with a decrease in nuclear Smad2 and NF-κB protein accumulation. GDF10 was silenced owing to its promoter hypermethylation, and it might originally act as a functional tumor suppressor via TGF-ß/Smad and NF-κB signaling pathways in NPC.

Suppression of RNF213, a susceptibility gene for moyamoya disease, inhibits endoplasmic reticulum stress through SEL1L upregulation.

RNF213, a susceptibility gene for moyamoya disease, is associated with stress responses to various stressors. We previously reported that Rnf213 knockout (KO) mitigated endoplasmic reticulum (ER) stress-induced diabetes in the Akita mouse model of diabetes. However, the role of RNF213 in ER stress regulation remains unknown. In the present study, RNF213 knockdown significantly inhibited the upregulation of ER stress markers (CHOP and spliced XBP1) by chemical ER stress-inducers in HeLa cells. Levels of SEL1L, a critical molecule in ER-associated degradation (ERAD), were increased by RNF213 knockdown, and SEL1L knockdown prevented the inhibitory effect of RNF213 suppression on ER stress in HeLa cells, indicating SEL1L involvement in this inhibition of ER stress. SEL1L upregulation was also confirmed in pancreatic islets of Rnf213 KO/Akita mice and in Rnf213 KO mouse embryonic fibroblasts. Additionally, RNF213 suppression increased levels of HRD1, which forms a complex with SEL1L to degrade misfolded protein in cells under ER stress. In conclusion, we demonstrate that RNF213 depletion inhibits ER stress possibly through elevation of the SEL1L-HRD1 complex, thereby promoting ERAD in vitro and in vivo.

Characterization of Moyamoya and Middle Cerebral Artery Diseases by Carotid Canal Diameter and RNF213 p.R4810K Genotype.

OBJECTIVES: It is sometimes difficult to differentiate middle cerebral artery disease from moyamoya disease because the two can present similarly yet have different treatment strategies. We investigated whether the presence of a narrow carotid canal and the RNF213 mutation can help differentiate between the two phenotypes. POPULATION AND METHODS: We analyzed 78 patients with moyamoya disease, 27 patients with middle cerebral artery disease, and 79 controls from 2 facilities. The carotid canal diameter was measured using computed tomography. The p.R4810K mutation was genotyped by TaqMan assay. A receiver operating characteristics analysis was performed to assess the significance of the carotid canal diameter for the accurate diagnosis of moyamoya disease. RESULTS: The carotid canal diameter was significantly narrower in patients with moyamoya disease than in controls. The optimal cutoff values were 5.0 mm for adult males and 4.5 mm for adult females and children (sensitivity: 0.82; specificity: 0.92). Among the patients with middle cerebral artery disease, 18.5% and 25.0% of the affected hemispheres had the p.R4810K mutation and narrow canal (i.e., below the cutoff), respectively, whereas only 3.1% of those had both. Contrastingly, 68.8% of the affected hemispheres in patients with moyamoya disease had both these characteristics. Among the patients with moyamoya disease, those with the p.R4810K mutation tended to have narrower carotid canals. CONCLUSIONS: Although the presence of a narrow carotid canal or the p.R4810K mutation alone could not be used to distinguish those with moyamoya disease from those with middle cerebral artery disease, the combination of these factors could better characterize the two phenotypes.

Influence of Epstein-Barr virus and human papillomavirus infection on macrophage migration inhibitory factor and macrophage polarization in nasopharyngeal carcinoma.

BACKGROUND: To assess the effects of Epstein-Barr virus (EBV) and human papillomavirus (HPV) infection on the tumor microenvironment, we examined the relationship between viral infection status, macrophage migration inhibitory factor (MIF), and tumor-associated macrophages in nasopharyngeal carcinoma (NPC). METHODS: A tissue microarray containing 150 cores from 90 patients with NPC and six with chronic inflammation was used. EBV and HPV status were detected using in situ hybridization with commercial EBER1 and HPV16/18 probes. Immunofluorescence double staining of MIF, pan-macrophage marker CD68, M1 macrophage marker CD11c, and M2 macrophage marker CD163 were analyzed using the same tissue microarray. The levels of these markers between NPC and inflammation cases and between tumor nests and stroma were compared. Correlations among these markers were analyzed. RESULTS: We found EBER1(+) cases in 90% of NPC patients, including 10% EBV/HPV co-infection. M1 macrophages mainly infiltrated the tumor nest, while M2 macrophages infiltrated the tumor stroma. We found a significant positive correlation between EBER1 levels and MIF levels in tumor nests and a significant positive correlation between HPV16/18 and CD11c(+) cell levels in NPC tissues. CONCLUSIONS: It is suggested that MIF is associated with EBV, and M1 macrophage infiltration is affected by HPV status in NPC.

Mutant KCNJ3 and KCNJ5 Potassium Channels as Novel Molecular Targets in Bradyarrhythmias and Atrial Fibrillation.

BACKGROUND: Bradyarrhythmia is a common clinical manifestation. Although the majority of cases are acquired, genetic analysis of families with bradyarrhythmia has identified a growing number of causative gene mutations. Because the only ultimate treatment for symptomatic bradyarrhythmia has been invasive surgical implantation of a pacemaker, the discovery of novel therapeutic molecular targets is necessary to improve prognosis and quality of life. METHODS: We investigated a family containing 7 individuals with autosomal dominant bradyarrhythmias of sinus node dysfunction, atrial fibrillation with slow ventricular response, and atrioventricular block. To identify the causative mutation, we conducted the family-based whole exome sequencing and genome-wide linkage analysis. We characterized the mutation-related mechanisms based on the pathophysiology in vitro. After generating a transgenic animal model to confirm the human phenotypes of bradyarrhythmia, we also evaluated the efficacy of a newly identified molecular-targeted compound to upregulate heart rate in bradyarrhythmias by using the animal model. RESULTS: We identified one heterozygous mutation, KCNJ3 c.247A>C, p.N83H, as a novel cause of hereditary bradyarrhythmias in this family. KCNJ3 encodes the inwardly rectifying potassium channel Kir3.1, which combines with Kir3.4 (encoded by KCNJ5) to form the acetylcholine-activated potassium channel ( IKACh channel) with specific expression in the atrium. An additional study using a genome cohort of 2185 patients with sporadic atrial fibrillation revealed another 5 rare mutations in KCNJ3 and KCNJ5, suggesting the relevance of both genes to these arrhythmias. Cellular electrophysiological studies revealed that the KCNJ3 p.N83H mutation caused a gain of IKACh channel function by increasing the basal current, even in the absence of m2 muscarinic receptor stimulation. We generated transgenic zebrafish expressing mutant human KCNJ3 in the atrium specifically. It is interesting to note that the selective IKACh channel blocker NIP-151 repressed the increased current and improved bradyarrhythmia phenotypes in the mutant zebrafish. CONCLUSIONS: The IKACh channel is associated with the pathophysiology of bradyarrhythmia and atrial fibrillation, and the mutant IKACh channel ( KCNJ3 p.N83H) can be effectively inhibited by NIP-151, a selective IKACh channel blocker. Thus, the IKACh channel might be considered to be a suitable pharmacological target for patients who have bradyarrhythmia with a gain-of-function mutation in the IKACh channel.

Combination of RERG and ZNF671 methylation rates in circulating cell-free DNA: A novel biomarker for screening of nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is a prevalent malignancy in Southeast Asia, hence, identifying easily detectable biomarkers for NPC screening is essential for better diagnosis and prognosis. Using genome-wide and targeted analyses based on next-generation sequencing approaches, we previously showed that gene promoters are hypermethylated in NPC tissues. To confirm whether DNA methylation rates of genes could be used as biomarkers for NPC screening, 79 histologically diagnosed NPC patients and 29 noncancer patients were recruited. A convenient quantitative analysis of DNA methylation using real-time PCR (qAMP) was carried out, involving pretreatment of tissue DNA, and circulating cell-free DNA (ccfDNA) from nonhemolytic plasma, with methylation-sensitive and/or methylation-dependent restriction enzymes. The qAMP analyses revealed that methylation rates of RERG, ZNF671, ITGA4, and SHISA3 were significantly higher in NPC primary tumor tissues compared to noncancerous tissues, with sufficient diagnostic accuracy of the area under receiver operating characteristic curves (AUC). Interestingly, higher methylation rates of RERG in ccfDNA were statistically significant and yielded a very good AUC; however, those of ZNF671, ITGA4, and SHISA3 were not significant. Furthermore, the combination of methylation rates of RERG and ZNF671 in ccfDNA showed higher diagnostic accuracy than either of them individually. In conclusion, the methylation rates of specific genes in ccfDNA can serve as novel biomarkers for early detection and screening of NPC.

Moyamoya disease patient mutations in the RING domain of RNF213 reduce its ubiquitin ligase activity and enhance NFκB activation and apoptosis in an AAA+ domain-dependent manner.

Moyamoya disease (MMD) is a cerebrovascular disease characterized by progressive occlusion of the internal carotid arteries. Genetic studies originally identified RNF213 as an MMD susceptibility gene that encodes a large 591 kDa protein with a functional RING domain and dual AAA+ ATPase domains. As the functions of RNF213 and its relationship to MMD onset are unknown, we set out to characterize the ubiquitin ligase activity of RNF213, and the effects of MMD patient mutations on these activities and on other cellular processes. In vitro ubiquitination assays, using the RNF213 RING domain, identified Ubc13/Uev1A as a key ubiquitin conjugating enzyme that together generate K63-linked polyubiquitin chains. However, nearly all MMD patient mutations in the RING domain greatly reduced this activity. When full-length proteins were overexpressed in HEK293T cells, patient mutations that abolished the ubiquitin ligase activities conversely enhanced nuclear factor κB (NFκB) activation and induced apoptosis accompanied with Caspase-3 activation. These induced activities were dependent on the RNF213 AAA+ domain. Our results suggest that the NFκB- and apoptosis-inducing functions of RNF213 may be negatively regulated by its ubiquitin ligase activity and that disruption of this regulation could contribute towards MMD onset.

Polyphenols with Anti-Amyloid ß Aggregation Show Potential Risk of Toxicity Via Pro-Oxidant Properties.

Alzheimer's disease (AD) is the most common form of dementia among older people. Amyloid ß (Aß) aggregation has been the focus for a therapeutic target for the treatment of AD. Naturally occurring polyphenols have an inhibitory effect on Aß aggregation and have attracted a lot of attention for the development of treatment strategies which could mitigate the symptoms of AD. However, considerable evidence has shown that the pro-oxidant mechanisms of polyphenols could have a deleterious effect. Our group has established an assay system to evaluate the pro-oxidant characteristics of chemical compounds, based on their reactivity with DNA. In this review, we have summarized the anti-Aß aggregation and pro-oxidant properties of polyphenols. These findings could contribute to understanding the mechanism underlying the potential risk of polyphenols. We would like to emphasize the importance of assessing the pro-oxidant properties of polyphenols from a safety point of view.

Proteomic analysis of the monkey hippocampus for elucidating ischemic resistance.

It is well-known that the cornu Ammonis 1 (CA1) sector of hippocampus is vulnerable for the ischemic insult, whereas the dentate gyrus (DG) is resistant. Here, to elucidate its underlying mechanism, alternations of protein oxidation and expression of DG in the monkey hippocampus after ischemia-reperfusion by the proteomic analysis were studied by comparing CA1 data. Oxidative damage to proteins such as protein carbonylation interrupt the protein function. Carbonyl modification of molecular chaperone, heat shock 70 kDa protein 1 (Hsp70.1) was increased remarkably in CA1, but slightly in DG. In addition, expression levels of nicotinamide adenine dinucleotide (NAD)-dependent protein deacetylase sirtuin-2 (SIRT2) was significantly increased in DG after ischemia, but decreased in CA1. Accordingly, it is likely that SIRT2 upregulation and negligible changes of carbonylation of Hsp70.1 exert its neuroprotective effect in DG. On the contrary, carbonylation level of dihydropyrimidinase related protein 2 (DRP-2) and l-lactate dehydrogenase B chain (LDHB) were slightly increased in CA1 as shown previously, but remarkably increased in DG after ischemia. It is considered that DRP-2 and LDHB are specific targets of oxidative stress by ischemia insult and high carbonylation levels of DRP-2 may play an important role in modulating ischemic neuronal death.

Prevalence of RNF213 p.R4810K Variant in Early-Onset Stroke With Intracranial Arterial Stenosis.

Background and Purpose- The ring finger protein 213 gene ( RNF213) is a susceptibility gene for moyamoya disease and large-artery ischemic stroke in East Asia. We examined the prevalence and correlates of the RNF213 p.R4810K variant in patients with early-onset ischemic stroke in a Japanese single-center cohort. Methods- We analyzed 70 early-onset stroke patients with intracranial arterial stenosis who developed a noncardioembolic stroke or transient ischemic attack from 20 to 60 years of age. Patients with moyamoya disease were excluded. Results- The RNF213 p.R4810K variant was found in 17 patients (24%), and more often in women than men (38% versus 16%, odds ratio 3.3; 95% CI, 1.1-10.2, P=0.04). The variant was identified in 35% of patients with stenosis in the M1 segment of the middle cerebral artery or the A1 segment of the anterior cerebral artery (odds ratio, 25.0; 95% CI, 1.4-438; P<0.01) but in only one patient (9%) with intracranial posterior circulation stenosis. Conventional atherosclerotic risk factors did not differ between variant carriers and noncarriers. Conclusions- The RNF213 p.R4810K variant is common in early-onset ischemic stroke with anterior circulation stenosis in Japan. Further investigation of the RNF213 gene will provide new insights into pathogenetic mechanisms of early-onset stroke.

RNF213 Is Associated with Intracranial Aneurysms in the French-Canadian Population.

Intracranial aneurysms (IAs) are the result of focal weakness in the artery wall and have a complex genetic makeup. To date, genome-wide association and sequencing studies have had limited success in identifying IA risk factors. Distinct populations, such as the French-Canadian (FC) population, have increased IA prevalence. In our study, we used exome sequencing to prioritize risk variants in a discovery cohort of six FC families affected by IA, and the analysis revealed an increased variation burden for ring finger protein 213 (RNF213). We resequenced RNF213 in a larger FC validation cohort, and association tests on further identified variants supported our findings (SKAT-O, p = 0.006). RNF213 belongs to the AAA+ protein family, and two variants (p.Arg2438Cys and p.Ala2826Thr) unique to affected FC individuals were found to have increased ATPase activity, which could lead to increased risk of IA by elevating angiogenic activities. Common SNPs in RNF213 were also extracted from the NeuroX SNP-chip genotype data, comprising 257 FC IA-affected and 1,988 control individuals. We discovered that the non-ancestral allele of rs6565666 was significantly associated with the affected individuals (p = 0.03), and it appeared as though the frequency of the risk allele had changed through genetic drift. Although RNF213 is a risk factor for moyamoya disease in East Asians, we demonstrated that it might also be a risk factor for IA in the FC population. It therefore appears that the function of RNF213 can be differently altered to predispose distinct populations to dissimilar neurovascular conditions, highlighting the importance of a population's background in genetic studies of heterogeneous disease.

Rapid contralateral progression of focal cerebral arteriopathy distinguished from RNF213-related moyamoya disease and fibromuscular dysplasia.

BACKGROUND: Focal cerebral arteriopathy includes unifocal or multifocal lesions that are unilateral or bilateral. Large- and/or medium-sized vessels are involved and can be visualized on angiography. CASE REPORT: We report a case of cerebral infarction in a 9-year-old Japanese female who presented with a transient ischemic attack. Steno-occlusion involving the distal part of the internal carotid artery, proximal middle cerebral artery, and anterior cerebral artery was observed. Digital subtraction angiography demonstrated a beaded appearance in the cervical portion of the diseased internal carotid artery. Revascularization surgery was performed 45 days after the onset. A new infarction appeared on the other side of the anterior cerebral artery territory 7 months after the first onset. Antiplatelets and vasodilators were administered, and no progression was observed during 18 months of follow-up. Genetic analysis did not show ring finger protein 213 (RNF213)-related moyamoya disease, and pathological examination revealed no characteristics of fibromuscular dysplasia. CONCLUSION: The radiological and genetic features coincided with focal cerebral arteriopathy, which is a distinct entity from fibromuscular dysplasia and RNF213-related moyamoya disease.

RNF213 p.R4810K Variant and Intracranial Arterial Stenosis or Occlusion in Relatives of Patients with Moyamoya Disease.

BACKGROUND: This study aimed to determine the effectiveness of genetic testing for the p.R4810K variant (rs112735431) of the Mysterin/RNF213 gene, which is associated with moyamoya disease and other intracranial vascular diseases, in the family members of patients with moyamoya disease. METHODS: We performed genotyping of the RNF213 p.R4810K polymorphism and magnetic resonance angiography on 59 relatives of 18 index patients with moyamoya disease. Nineteen individuals had follow-up magnetic resonance angiography with a mean follow-up period of 7.2 years. RESULTS: Six of the 34 individuals with the GA genotype (heterozygotes for p.R4810K) showed intracranial steno-occlusive lesions in the magnetic resonance angiography, whereas none of the 25 individuals with the GG genotype (wild type) showed any abnormalities. Follow-up magnetic resonance angiography revealed de novo lesions in 2 and disease progression in 1 of the 11 individuals with the GA genotype, despite none of the 8 individuals with the GG genotype showing any changes. Accordingly, 8 individuals had steno-occlusive lesions at the last follow-up, and all had the p.R4810K risk variant. The prevalence of steno-occlusive intracranial arterial diseases in family members with the p.R4810K variant was 23.5% (95% confidence interval: 9.27%-37.78%), which was significantly higher than in those without the variant (0%, P = .0160). CONCLUSIONS: Genotyping of the p.R4810K missense variant is useful for identifying individuals with an elevated risk for steno-occlusive intracranial arterial diseases in the family members of patients with moyamoya disease.

Paroxysmal limb intolerable pain (infantile pain episodes associated with novel Nav1.9 mutations in familial episodic pain syndrome).

Painful peripheral neuropathy has been correlated with various voltage-gated sodium channel mutations in sensory neurons. Recently Navl.9, a voltage-gated sodium channel sub- type, has been established as a genetic influence for certain peripheral pain syndromes. Herein, we performed a genetic study in six unrelated, multigenerational Japanese families with episodic pain syndrome. Affected participants were characterized by infantile recurrent pain episodes, with spontaneous mitigation around adolescence. The affected joints, in an in- creasing order of frequency, include those in the knees, ankles, wrists, and elbows. The pain typically lasts for 15-30 min and recurs several times a day. The pain is often induced by fa- tigue and is a prelude of bad weather. The affected regions feel cold in the patients, and warming the lesions relieves the symptoms. This unique phenotype was inherited in an autosomal-dominant mode. Two missense var- iants, p.R222S and p.R222H, were identified in SCN11A by linkage analysis and exome analy- sis. Next, we generated a knock-in mouse model harboring one of the mutations (p.R222S). Behavioral tests showed that p.R222S mice were significantly more hypersensitive to hot and cold stimuli. Electrophysiological studies using dorsal ganglion neurons showed significant increase of input impedance and firing frequency of evoked action potentials in p.R222S mice. These results suggest that the novel mutation reported herein is a gain-of-function mu- tation that causes infantile familial episodic pain.

Significant Association of the RNF213 p.R4810K Polymorphism with Quasi-Moyamoya Disease.

BACKGROUND: Quasi-moyamoya disease is an angiographical moyamoya disease equivalent accompanied by known underlying diseases. Mysterin/RNF213 is a major susceptibility gene for moyamoya disease, of which the p.R4810K variant is a founder polymorphism. The genetics of quasi-moyamoya disease is poorly understood, therefore, this study investigated a potential association between the p.R4810K polymorphism and quasi-moyamoya disease. METHODS: Genotyping of the p.R4810K variant was performed on 18 quasi-moyamoya disease cases and 91 controls, who visited Kyoto University Hospital or Kobe City Medical Center, Japan, between 2006 and 2015. RESULTS: The p.R4810K variant was found in 12 of 18 quasi-moyamoya disease patients. The frequency of p.R4810K carriers was significantly higher in quasi-moyamoya disease cases than in controls (66.7% versus 2.2%, odds ratio 89.0, 95% confidence interval: 19.2-669.4). CONCLUSIONS: Our data showed that the RNF213 p.R4810K polymorphism was significantly associated with quasi-moyamoya disease.