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.

Posterior cerebral artery involvement in unilateral moyamoya disease is exclusively ipsilateral and influenced by RNF213 mutation gene dose: The SUPRA Japan study: PCA involvement in unilateral moyamoya.

OBJECTIVES: The characteristics and clinical implications of posterior cerebral artery (PCA) involvement in unilateral moyamoya disease (U-MMD), such as laterality, frequency of the RNF213 p.R4810K mutation, and clinical outcomes, have not been well studied. POPULATION AND METHODS: We analyzed a cohort of 93 patients with U-MMD who participated in the SUPRA Japan study. Clinical characteristics and radiological examinations were collected from medical records. The presence of the p.R4810K mutation was determined using a TaqMan assay. The clinical outcome was assessed using the modified Rankin Scale (mRS). Univariate and multivariate logistic regression analyses were performed to assess the associations. RESULTS: Among the patients with U-MMD, PCA involvement was observed in 60.0 % (3/5) of patients with homozygous mutation, 11.3 % (7/62) of those with heterozygous mutation, and 3.8 % (1/26) of those with wild type, showing a significant linear trend (p < 0.001 for trend). PCA involvement was observed exclusively on the same side as the affected anterior circulation. Dyslipidemia and cerebral infarction at initial onset were independently associated with mRS ≥1. Hypertension was associated with mRS ≥1 and it was also linked to infarction at initial onset, suggesting a potential confounding effect. Although PCA involvement showed a trend for higher mRS, it was not statistically significant. CONCLUSIONS: Our findings indicate a gene dose effect of the p.R4810K mutation on PCA involvement, with the homozygous state showing the most significant effect. Both genetic and modifiable factors such as dyslipidemia may influence the progression of U-MMD.

Reduced pain sensitivity of episodic pain syndrome model mice carrying a Nav1.9 mutation by ANP-230, a novel sodium channel blocker.

The sodium channel Nav1.9 is expressed in the sensory neurons of small diameter dorsal root ganglia that transmit pain signals, and gain-of-function Nav1.9 mutations have been associated with both painful and painless disorders. We initially determined that some Nav1.9 mutations are responsible for familial episodic pain syndrome observed in the Japanese population. We therefore generated model mice harboring one of the more painful Japanese mutations, R222S, and determined that dorsal root ganglia hyperexcitability was the cause of the associated pain. ANP-230 is a novel non-opioid drug with strong inhibitory effects on Nav1.7, 1.8 and 1.9, and is currently under clinical trials for patients suffering from familial episodic pain syndrome. However, little is known about its mechanism of action and effects on pain sensitivity. In this study, we therefore investigated the inhibitory effects of ANP-230 on the hypersensitivity of Nav1.9 p.R222S mutant model mouse to pain. In behavioral tests, ANP-230 reduced the pain response of the mice, particularly to heat or mechanical stimuli, in a concentration- and time-dependent manner. Furthermore, ANP-230 suppressed the repetitive firing of dorsal root ganglion neurons of these mutant mice. Our results clearly demonstrate that ANP-230 is an effective analgesic for familial episodic pain syndrome resulting from DRG neuron hyperexcitability, and that such analgesic effects are likely to be of clinical significance.

Formation and Degradability of Per- and Polyfluoroalkyl Substances in River Soils around a Fluoropolymer-Manufacturing Plant in Osaka, Japan.

Our previous studies reported that perfluorooctanoic acid (PFOA) contamination decreased in well, tap, and surface water around a fluoropolymer plant in Osaka, Japan, between 2003 and 2016. In this study, we evaluated the degradability of PFOA and perfluorohexanoic acid in river soils to identify the influence of the degradation on the perfluorocarboxylic acids (PFCAs) in the Yodo River Basin. We also investigated the influence of abiotic oxidation on the formation of PFCAs in soils and measured the fluorotelomer alcohols (FTOHs) as precursors of PFCAs in the soil and air samples collected at Osaka and Kyoto. No major degradations were observed in soils contaminated with PFCA during the 24-week experimental period, while the PFOA levels increased only in the control group. The PFCA levels significantly increased after oxidation in this group. The dominant FTOH in soils was 10:2 FTOH, whereas 6:2 FTOH was dominant in the air samples. These findings suggest that PFOA was rapidly removed from water system but persist in soils. Moreover, the results indicate the need to evaluate not only the PFCAs, but also the FTOHs and other precursors for the accurate prediction of PFCA accumulation and fates in the environment.

Profiles and determinants of dicofol, endosulfans, mirex, and toxaphenes in breast milk samples from 10 prefectures in Japan.

Human exposure to persistent organic pollutants (POPs) is reflected by POP concentrations in breast milk. Many studies of POPs in breast milk have been performed in Japan, but insufficient information is available about some legacy POPs (e.g., mirex and toxaphenes, included in the Stockholm Convention in 2001) and novel POPs (e.g., dicofol and endosulfans, included in the Stockholm Convention in 2019 and 2011, respectively). In this study, dicofol, endosulfan, mirex, and toxaphene concentrations in breast milk from 10 prefectures in Japan were determined. The samples were collected between 2005 and 2010, before Stockholm Convention restrictions on endosulfans and mirex were implemented. Common POPs (e.g., polychlorinated biphenyls) were also analyzed to allow the contamination statuses to be compared. The α-endosulfan and ß-endosulfan concentrations were 0.26-13 and 0.012-0.82 ng/g lipid, respectively. The toxaphene #26 and #50 concentrations were <0.08-5.6 and < 0.1-8.5 ng/g lipid, respectively. The dicofol concentrations were <0.01-4.8 ng/g lipid. The mirex concentrations were <0.2-3.5 ng/g lipid. The α- and ß-endosulfan concentrations on a lipid weight basis negatively correlated with the lipid contents of the milk samples (ρ = -0.65, p < 0.01 for α-endosulfan; ρ = -0.58, p < 0.01 for ß-endosulfan). The toxaphene concentrations positively correlated with the lipid contents. The mirex concentrations positively correlated with the maternal age but negatively correlated with the maternal body mass index. No correlations between the dicofol concentrations and the factors were found. Principal component analysis divided the data into four groups, (1) chlordanes, dichlorodiphenyltrichloroethanes and related compounds, hexachlorobenzene, hexachlorocyclohexanes, hexachloroethane, and polychlorinated biphenyls, (2) endosulfans, (3) dicofol, dieldrin, and toxaphenes, and (4) bromodiphenyl ether 47. This indicated that bromodiphenyl ether 47, dicofol, endosulfans, and toxaphenes have different exposure routes or different kinetics to the other legacy POPs.

Increased abundance of Ruminococcus gnavus in gut microbiota is associated with moyamoya disease and non-moyamoya intracranial large artery disease.

Moyamoya disease (MMD) is a rare cerebrovascular disease endemic in East Asia. The p.R4810K mutation in RNF213 gene confers a risk of MMD, but other factors remain largely unknown. We tested the association of gut microbiota with MMD. Fecal samples were collected from 27 patients with MMD, 7 patients with non-moyamoya intracranial large artery disease (ICAD) and 15 control individuals with other disorders, and 16S rRNA were sequenced. Although there was no difference in alpha diversity or beta diversity between patients with MMD and controls, the cladogram showed Streptococcaceae was enriched in patient samples. The relative abundance analysis demonstrated that 23 species were differentially abundant between patients with MMD and controls. Among them, increased abundance of Ruminococcus gnavus > 0.003 and decreased abundance of Roseburia inulinivorans < 0.002 were associated with higher risks of MMD (odds ratio 9.6, P = 0.0024; odds ratio 11.1, P = 0.0051). Also, Ruminococcus gnavus was more abundant and Roseburia inulinivorans was less abundant in patients with ICAD than controls (P = 0.046, P = 0.012). The relative abundance of Ruminococcus gnavus or Roseburia inulinivorans was not different between the p.R4810K mutant and wildtype. Our data demonstrated that gut microbiota was associated with both MMD and ICAD.

Lack of Association between Seropositivity of Vasculopathy-Related Viruses and Moyamoya Disease.

OBJECTIVES: Although the association between genetic factors, such as RNF213 mutations, and moyamoya disease (MMD) has been well investigated, environmental factors are largely undetermined. Thus, we aimed to examine whether viral infection increases the risk of MMD. MATERIALS AND METHODS: To eliminate the effect of presence or absence of the RNF213 p.R4810K mutation, the entire study population was positive for this mutation. We collected whole blood from 111 patients with MMD (45 familial and 66 sporadic cases) and 67 healthy volunteers, and we measured the immunoglobulin G titer of 11 viruses (cytomegalovirus, varicella-zoster virus, measles virus, rubella virus, herpes simplex virus, mumps virus, Epstein-Barr virus, human parvovirus B19, human herpesvirus 6 [HHV6], human herpesvirus 8, and John Cunningham virus) that were presumed to be associated with vasculopathy using the enzyme-linked immunosorbent assay. Positivity for past viral infection was determined by cut-off values obtained from previous reports and the manufacturer's instructions, and the positive rate was compared between cases and age- and sex-matched controls. We performed familial case-specific and sporadic case-specific analyses, as well as a case-control analysis. RESULTS: There was no significant difference in the positive rate between the case group and the control group in any of the analyses. A significant difference was only observed in the combined case-control analysis for HHV6 (p = 0.046), but the viral antibody-positive rate in control individuals was higher than in MMD cases. CONCLUSIONS: Our cross-sectional study suggest that the investigated 11 viruses including HHV6 are unlikely to have an impact on MMD development.

Moyamoya disease: diagnosis and interventions.

Moyamoya disease is a rare cause of stroke, radiologically characterised by progressive stenosis of the terminal portion of the internal carotid arteries and compensatory capillary collaterals. The discovery that RNF213, which encodes an unconventional E3 ubiquitin ligase, is the major susceptibility gene for moyamoya disease in people from east Asia has opened new avenues for investigation into the mechanisms of disease and potential treatment targets. The Arg4810Lys variant of the gene is most strongly associated with moyamoya disease, but the penetrance is lower than 1%, suggesting a synergistic relationship with additional environmental and genetic risk factors. White people carry less common non-Arg4810Lys variants of RNF213, which partly explains the lower prevalence of moyamoya disease in European countries and in the USA than in east Asian countries. Several monogenic moyamoya syndromes possess the radiological characteristics of moyamoya disease and have been associated with multiple genes and pathways involved in moyamoya angiopathy pathogenesis. Further clarification of the genetic and environmental factors that contribute to the emergence of moyamoya angiopathy could enable development of new treatment strategies for moyamoya disease.

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.

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.

Deletion of Gdf15 Reduces ER Stress-induced Beta-cell Apoptosis and Diabetes.

Endoplasmic reticulum (ER) stress contributes to pancreatic beta-cell apoptosis in diabetes, but the factors involved are still not fully elucidated. Growth differentiation factor 15 (GDF15) is a stress response gene and has been reported to be increased and play an important role in various diseases. However, the role of GDF15 in beta cells in the context of ER stress and diabetes is still unclear. In this study, we have discovered that GDF15 promotes ER stress-induced beta-cell apoptosis and that downregulation of GDF15 has beneficial effects on beta-cell survival in diabetes. Specifically, we found that GDF15 is induced by ER stress in beta cells and human islets, and that the transcription factor C/EBPß is involved in this process. Interestingly, ER stress-induced apoptosis was significantly reduced in INS-1 cells with Gdf15 knockdown and in isolated Gdf15 knockout mouse islets. In vivo, we found that Gdf15 deletion attenuates streptozotocin-induced diabetes by preserving beta cells and insulin levels. Moreover, deletion of Gdf15 significantly delayed diabetes development in spontaneous ER stress-prone Akita mice. Thus, our findings suggest that GDF15 contributes to ER stress-induced beta-cell apoptosis and that inhibition of GDF15 may represent a novel strategy to promote beta-cell survival and treat diabetes.

Genetic and nongenetic factors for contralateral progression of unilateral moyamoya disease: the first report from the SUPRA Japan Study Group.

OBJECTIVE: Although many studies have analyzed risk factors for contralateral progression in unilateral moyamoya disease, they have not been fully elucidated. The aim of this study was to examine whether genetic factors as well as nongenetic factors are involved in the contralateral progression. METHODS: The authors performed a multicenter cohort study in which 93 cases with unilateral moyamoya disease were retrospectively reviewed. The demographic features, RNF213 R4810K mutation, lifestyle factors such as smoking and drinking, past medical history, and angiographic findings were analyzed. A Cox proportional hazards model was used to find risk factors for contralateral progression. RESULTS: Contralateral progression was observed in 24.7% of cases during a mean follow-up period of 72.2 months. Clinical characteristics were not significantly different between 67 patients with the R4810K mutation and those without it. Cox regression analysis showed that the R4810K mutation (hazard ratio [HR] 4.64, p = 0.044), childhood onset (HR 7.21, p < 0.001), male sex (HR 2.85, p = 0.023), and daily alcohol drinking (HR 4.25, p = 0.034) were independent risk factors for contralateral progression. CONCLUSIONS: These results indicate that both genetic and nongenetic factors are associated with contralateral progression of unilateral moyamoya disease. The findings would serve to help us better understand the pathophysiology of moyamoya disease and to manage patients more appropriately.

Hantavirus infection as a risk factor for chronic kidney disease of unknown aetiology (CKDu) and its prevalence in endemic areas of Sri Lanka since 2010 according to a retrospective serological analysis.

Background. Chronic kidney disease of unknown aetiology (CKDu) is a major public health problem in Sri Lanka, especially among agrarian communities. Although the cause of CKDu is still unknown, hantavirus infection has been proposed as a risk factor.Methods. This study was performed using serological samples collected from two CKDu-endemic areas, Anuradhapura (2010) and Badulla districts (2010 and 2016), and a non-endemic area, Matale (2016) district. The presence of anti-Thailand orthohantavirus IgG antibodies was investigated in serum samples. Hantavirus seroprevalence and demographic data were epidemiologically analysed.Results. Seroprevalence was higher in CKDu patients (40.6-60.0 %) and healthy individuals in CKDu-endemic areas (17.6-25.5 %) than in healthy individuals in non-endemic areas (3.0 %). Statistically significant odds ratios (ORs) for hantavirus infection in CKDu patients were detected in CKDu-endemic areas [ORs: 3.2 and 3.1; 95 % confidence interval (CI): 1.8-5.5 and 1.8-5.2 in Anuradhapura and Badulla districts in 2010; and OR: 4.4, 95 % CI: 2.3-8.5 in 2016 in Badulla district). Furthermore, the OR for hantavirus infection in Badulla district has increased in the last decade from 3.1 (95 % CI: 1.8-5.3) to 4.4 (95 % CI: 2.3-8.5).Conclusion. Hantavirus infection has been prevalent in two distant CKDu-endemic areas since 2010. The observed significant association of hantavirus seropositivity with CKDu indicates a possible role of hantavirus infection in CKDu pathogenesis.

Characteristics of superficial esophageal squamous cell carcinomas undetectable with narrow-band imaging endoscopy.

BACKGROUND: The detection rate of narrow-band imaging (NBI) for superficial esophageal squamous cell carcinoma (SESCC), including high-grade intraepithelial neoplasia, is significantly higher than that of white-light endoscopy. However, there are SESCCs that are undetectable by NBI but detectable by Lugol chromoendoscopy (LCE) and the characteristics of these SESCCs are still unknown. Thus, this study aimed to clarify the characteristics of SESCC that are undetectable using NBI. METHODS: Patients with current SCC or a history of SCC in the head and neck or in the esophagus were enrolled. The inspection of the esophagus was initiated by NBI, followed by LCE. Biopsies were taken of all suspected SESCC lesions during NBI observation and Lugol-voiding lesions (LVLs) that were irregularly shaped and >5 mm and/or pink in color during LCE observation. The characteristics of SESCC that were undetectable with NBI were statistically analysed. RESULTS: Overall, 147 lesions in 105 cases were histologically diagnosed as SESCC. Twenty in 15 cases were NBI-undetectable lesions, all of which were macroscopic flat type (0-IIb). The median sizes of the NBI-undetectable lesions and NBI-detectable lesions were both 15 mm (P = 0.47). Multivariate analysis revealed independent factors for NBI-undetectable lesions such as numerous irregularly shaped LVLs (odds ratio [OR]: 4.94, 95% confidence interval [CI]: 1.39-17.5, P < 0.05) and anterior wall position (OR: 4.99, 95% CI: 1.58-15.8, P < 0.05). CONCLUSIONS: The detection of SESCCs with NBI is challenging when lesions are morphologically completely flat, in cases with numerous irregularly shaped LVLs, and if located at the anterior wall.

Alterations in ß-Cell Sphingolipid Profile Associated with ER Stress and iPLA2ß: Another Contributor to ß-Cell Apoptosis in Type 1 Diabetes.

Type 1 diabetes (T1D) development, in part, is due to ER stress-induced ß-cell apoptosis. Activation of the Ca2+-independent phospholipase A2 beta (iPLA2ß) leads to the generation of pro-inflammatory eicosanoids, which contribute to ß-cell death and T1D. ER stress induces iPLA2ß-mediated generation of pro-apoptotic ceramides via neutral sphingomyelinase (NSMase). To gain a better understanding of the impact of iPLA2ß on sphingolipids (SLs), we characterized their profile in ß-cells undergoing ER stress. ESI/MS/MS analyses followed by ANOVA/Student's t-test were used to assess differences in sphingolipids molecular species in Vector (V) control and iPLA2ß-overexpressing (OE) INS-1 and Akita (AK, spontaneous model of ER stress) and WT-littermate (AK-WT) ß-cells. As expected, iPLA2ß induction was greater in the OE and AK cells in comparison with V and WT cells. We report here that ER stress led to elevations in pro-apoptotic and decreases in pro-survival sphingolipids and that the inactivation of iPLA2ß restores the sphingolipid species toward those that promote cell survival. In view of our recent finding that the SL profile in macrophages-the initiators of autoimmune responses leading to T1D-is not significantly altered during T1D development, we posit that the iPLA2ß-mediated shift in the ß-cell sphingolipid profile is an important contributor to ß-cell death associated with T1D.

Identification of Novel Rodent-Borne Orthohantaviruses in an Endemic Area of Chronic Kidney Disease of Unknown Etiology (CKDu) in Sri Lanka.

We reported the genetic evidence of circulating hantaviruses from small mammals captured in a chronic kidney disease of unknown etiology (CKDu) hotspot area of Sri Lanka. The high seroprevalence of anti-hantavirus antibodies against Thailand orthohantavirus (THAIV) has been reported among CKDu patients and rodents in Sri Lankan CKDu hotspots. We captured 116 small mammals from CKDu endemic regions in the Polonnaruwa District of Sri Lanka. Seven animals (five out of 11 Mus booduga and two out of 99 Rattus rattus) were PCR-positive for the hantavirus. A rat-borne sequence was grouped with a THAIV-like Anjozorobe virus. In contrast, Mus-borne sequences belonged to the THAIV lineage, suggesting a novel orthohantavirus species according to the phylogenetic analyses and whole-genome comparisons. Our genetic evidence indicates the presence of two THAIV-related viruses circulating in this CKDu endemic area, suggesting a basis for further investigations to identify the infectious virus in patients with CKDu and the CKDu induction mechanism of these viruses.

RNF213 p.R4810K (c.14429G > A) Variant Determines Anatomical Variations of the Circle of Willis in Cerebrovascular Disease.

INTRODUCTION: Dysregulation of the RING finger protein 213 (RNF213) gene impairs vascular formation in experimental animal models. In addition, vascular abnormalities in the circle of Willis are associated with cerebrovascular disease. Here, we evaluated the relationship between the East Asian founder variant RNF213 p.R4810K and consequent anatomical variations in the circle of Willis in cerebrovascular disease. PATIENTS AND METHODS: The present study is an observational cross-sectional study. It included patients with acute anterior circulation non-cardioembolic stroke admitted to our institution within 7 days of symptom onset or last-known-well from 2011 to 2019, and those who participated in the National Cerebral and Cardiovascular Center Biobank. We compared anatomical variations of the vessels constituting the circle of Willis between RNF213 p.R4810K (c.14429G > A) variant carriers and non-carriers using magnetic resonance angiography and assessed the association between the variants and the presence of the vessels constituting the circle of Willis. Patients with moyamoya disease were excluded. RESULTS: Four hundred eighty-one patients [146 women (30%); median age 70 years; median baseline National Institutes of Health Stroke Scale score 5] were analyzed. The RNF213 p.R4810K variant carriers (n = 25) were more likely to have both posterior communicating arteries (PComAs) than the variant non-carriers (n = 456) (56% vs. 13%, P < 0.01). Furthermore, variant carriers were less likely to have an anterior communicating artery (AComA) than non-carriers (68% vs. 84%, P = 0.04). In a multivariate logistic regression analysis, the association of RNF213 p.R4810K variant carriers with the presence of both PComAs and the absence of AComA remained significant. CONCLUSION: Our findings suggest that the RNF213 p.R4810K variant is an important factor in determining anatomical variations in the circle of Willis.

Deletion of 2 amino acids in IHH in a Japanese family with brachydactyly type A1.

BACKGROUND: Brachydactyly type A1 (BDA1) is an autosomal dominant disorder characterized by uniform shortening of the middle phalanges in all digits. It is associated with variants in the Indian Hedgehog (IHH) gene, which plays a key role in endochondral ossification. To date, heterozygous pathogenic IHH variants involving several codons, which are restricted to a specific region of the N-terminal active fragment of IHH, have been reported. The purpose of this study was to identify the pathogenic variant in a Japanese family with BDA1 and to evaluate its pathogenesis with regard to previous reports. METHODS: The proband, a 9-year-old boy, his siblings, and his father had shortened digits and a short stature of variable severity. Based on physical examinations, radiographic findings and family history, they were diagnosed with BDA1. This family is the first case of an isolated malformation in Japan. Sanger sequencing of IHH was performed on these individuals and on the proband's unaffected mother. The significance of the variants was assessed using three-dimensional analysis methods. RESULTS: Sanger sequencing showed a novel IHH heterozygous variant, NM_002181.4:c.544_549delTCAAAG(p.Ser182Lys183del) [NC_000002.12:g.219057461_219057466del].. These two residues are located outside the cluster region considered a hotspot of pathogenic variants. Three-dimensional modelling showed that S182 and K183 are located on the same surface as other residues associated with BDA1. Analysis of residue interactions across the interface between IHH and its interacting receptor protein revealed the presence of hydrogen bonds between them. CONCLUSIONS: We report a novel variant, NM_002181.4:c.544_549delTCAAAG (p.Ser182Lys183del) [NC_000002.12:g.219057461_219057466del] in a Japanese family with BDA1. Indeed, neither variations in codons 182 or 183 nor with such two-amino-acid deletions in IHH have been reported previously. Although these two residues are located outside the cluster region considered a hotspot of pathogenic variants, we speculate that this variant causes BDA1 through impaired interactions between IHH and target receptor proteins in the same manner as other pathogenic variants located in the cluster region. This report expands the genetic spectrum of BDA1.

E44Q mutation in NaV1.7 in a patient with infantile paroxysmal knee pain: electrophysiological analysis of voltage-dependent sodium current.

Gain-of-function mutations in voltage-gated sodium channels (NaV1.7, NaV1.8, and NaV1.9) are known causes of inherited pain disorders. Identification and functional assessment of new NaV1.7 mutations could help elucidate the phenotypic spectrum of NaV1.7 channelopathies. We identified a novel NaV1.7 mutation (E44Q in exon 2) that substitutes a glutamic acid residue for glutamine in the cytoplasmic N-terminus of NaV1.7 in a patient with paroxysmal pain attacks during childhood and his family who experienced similar pain episodes. To study the sodium channel's function, we performed electrophysiological recordings. Voltage-clamp recordings revealed that the mutation increased the amplitude of the non-inactivating component of the sodium current, which might facilitate channel opening. These data demonstrate that E44Q is a gain-of-function mutation in NaV1.7, which is consistent with our patient's pain phenotype.