Renal hypouricemia is an inherited disorder characterized by impaired tubular uric acid transport. Impairment of the function of URAT1, the main transporter for the reabsorption of uric acid at the apical membrane of the renal tubules, causes renal hypouricemia. The G774A mutation in the SLC22A12 gene encoding URAT1 predominates in Japanese renal hypouricemia. From data on linkage disequilibrium between the G774 locus and the 13 markers flanking it (12 single nucleotide polymorphisms and 1 dinucleotide insertion/deletion locus), we here estimate the age of this mutation at approximately 6820 years [95% confidence interval (CI) 1860–11,760 years; median = 2460 years]. This indicates that the origin of the G774A mutation dates back from between the time when the Jomon people predominated in Japan and the time when the Yayoi people started to migrate to Japan from the Korean peninsula. These data are consistent with a recent finding that this G774A mutation was also predominant in Koreans with hypouricemia and indicate that the mutation originated on the Asian continent. Thus, this mutation found in Japanese patients was originally brought by immigrant(s) from the continent and thereafter expanded in the Japanese population either by founder effects or by genetic drift (or both).
Statistical imputation of classical human leukocyte antigen (HLA) alleles is becoming an indispensable tool for fine-mappings of disease association signals from case–control genome-wide association studies. However, most currently available HLA imputation tools are based on European reference populations and are not suitable for direct application to non-European populations. Among the HLA imputation tools, The HIBAG R package is a flexible HLA imputation tool that is equipped with a wide range of population-based classifiers; moreover, HIBAG R enables individual researchers to build custom classifiers. Here, two data sets, each comprising data from healthy Japanese individuals of difference sample sizes, were used to build custom classifiers. HLA imputation accuracy in five HLA classes (HLA-A, HLA-B, HLA-DRB1, HLA-DQB1 and HLA-DPB1) increased from the 82.5–98.8% obtained with the original HIBAG references to 95.2–99.5% with our custom classifiers. A call threshold (CT) of 0.4 is recommended for our Japanese classifiers; in contrast, HIBAG references recommend a CT of 0.5. Finally, our classifiers could be used to identify the risk haplotypes for Japanese narcolepsy with cataplexy, HLA-DRB1*15:01 and HLA-DQB1*06:02, with 100% and 99.7% accuracy, respectively; therefore, these classifiers can be used to supplement the current lack of HLA genotyping data in widely available genome-wide association study data sets.
We evaluated the effects of the use of nonsteroidal anti-inflammatory drugs (NSAIDs) on endoscopic and histological findings in patients with rheumatoid arthritis (RA) before and after the eradication of Helicobacter pylori infection. Helicobacter pylori (H. pylori) eradication using lansoprazole 30 mg, amoxicillin 750 mg, and clarithromycin 200 mg twice daily for 1 week was conducted in 44 patients (mean age: 56.5 years) with RA. Using the updated Sydney system, endoscopic and histological findings of the greater curvature of the antrum, the greater curvature of the upper corpus, and the lesser curvature of the lower corpus were compared before and after eradication, for a mean follow-up period of 3.5 months. Overall, H. pylori eradication was successful in 32 patients (72.7%). Of these 32 patients, 23 were NSAID users. In the successful eradication group, (1) there was no significant change on endoscopic findings, including gastric erythema and erosion in all three regions irrespective of NSAIDs use; (2) of 17 active ulcers before eradication in NSAIDs users, all healed except for one duodenal ulcer that persisted, where one patient newly developed a gastric ulcer, one developed erosive duodenitis, and two developed reflux esophagitis, all in NSAID users; (3) neutrophil infiltration and chronic inflammation were significantly improved in all three regions after H. pylori eradication irrespective of use of NSAIDs, while atrophic change and intestinal metaplasia did not change. In the eradication failure group; (1) there was no significant change on endoscopic and histological findings in the three regions; (2) two of three ulcers present before eradication on NSAID users persisted even after eradication, and no new cases of gastric ulcer or erosive duodenitis occurred. In conclusion, over a mean follow-up period of 3.5 months, use of NSAIDs in Japanese patients with RA did not impair the healing process of gastric and duodenal ulcers nor did it affect the endoscopic and histological improvements associated with H. pylori eradication.
The aim of this study was to evaluate the factors responsible for depressed mood in rheumatoid arthritis (RA). Clinical and laboratory measures were collected from 4558 RA patients enrolled in a large clinical cohort study for RA conducted at the Institute of Rheumatology, Tokyo Women's Medical University (IORRA study). A two-question depressed screening included in the U.S. Preventive Services Task Force recommendation were utilized to identify "depressed patients." A total of 1875 (41.1%) were identified as "depressed patients" who presented with symptoms suggestive of depression. Patient's Visual Analog Scale (VAS) for general health (43.3 mm vs 24.6 mm, P < 0.0001) and pain (40.9 mm vs 23.8 mm, P < 0.0001) and the disability index scores measured by the Health Association Questionnaire (HAQ) (0.986 vs 0.574, P < 0.0001) were significantly higher in depressed patients than in nondepressed patients. The presence of three or more comorbidities (odds ratio [OR] 2.157, P < 0.0001), infection (OR 1.754, P < 0.0001), and joint surgery (OR 1.878, P < 0.0001) were significantly correlated with depressed mood in RA. The results of the Generalized Linear Model analysis showed that HAQ disability index (P < 0.0001) and patient's VAS for general health (P < 0.0001) were also strongly and significantly associated to the response variable "probability of depressed patients.' Patient appraisal of poor general health and greater disability were associated with depressed mood in RA.
Abstract Background: Cellular energetics play an important role in Parkinsons disease etiology, but no treatments directly address this deficiency. Our past research showed that treatment with febuxostat and inosine increased blood hypoxanthine and ATP in healthy adults, and a preliminary trial in 3 Parkinson's disease patients suggested some symptomatic improvements with no adverse effects. Methods: To examine the efficacy on symptoms and safety in a larger group of Parkinsons disease patients, we conducted a single-arm, open-label trial at 5 Japanese neurology clinics and enrolled thirty patients ( n males = 11; n females = 19); 26 patients completed the study ( n males = 10; n females = 16). Each patient was administered febuxostat 20 mg and inosine 500 mg twice-per-day (after breakfast and dinner) for 8 weeks. The primary endpoint was the difference of MDS-UPDRS Part III score immediately before and after 57 days of treatment. Results: Serum hypoxanthine concentrations were raised significantly after treatment (Pre = 11.4 μM; Post = 38.1 μM; P < .0001). MDS-UPDRS Part III score was significantly lower after treatment (Pre = 28.1 ± 9.3; Post = 24.7 ± 10.8; mean ± SD; P = .0146). Sixteen adverse events occurred in 13/29 (44.8%) patients, including 1 serious adverse event (fracture of the second lumbar vertebra) that was considered not related to the treatment. Conclusions: The results of this study suggest that co-administration of febuxostat and inosine is relatively safe and effective for improving symptoms of Parkinsons disease patients. Further controlled trials need to be performed to confirm the symptomatic improvement and to examine the disease-modifying effect in long-term trials.
Previous reports have described several associations of PR, QRS, QT and heart rate with genomic variations by genome-wide association studies (GWASs). In the present study, we examined the association of ∼2.5 million SNPs from 2994 Japanese healthy volunteers obtained from the JPDSC database with electrocardiographic parameters. We confirmed associations of PR interval, QRS duration and QT interval in individuals of Japanese ancestry with 11 of the 45 SNPs (6 of 20 for QT, 5 of 19 for PR and 0 of 6 for QRS) observed among individuals of European, African and Asian (Indian and Korean) ancestries. Those results indicate that many of the electrocardiographic associations with genes are shared by different ethnic groups including Japanese. Possible novel associations found in this study were validated by Korean data. As a result, we identified a novel association of SNP rs4952632[G] (maps near SLC8A1, sodium–calcium exchanger) (P = 7.595 × 10−6) with PR interval in Japanese individuals, and replication testing among Koreans confirmed the association of the same SNP with prolonged PR interval. Meta-analysis of the Japanese and Korean datasets demonstrated highly significant associations of SNP rs4952632[G] with a 2.325-ms (95% CI, 1.693–2.957 ms) longer PR interval per minor allele copy (P = 5.598 × 10−13). Cell-type-specific SLC8A1 knockout mice have demonstrated a regulatory role of sodium–calcium exchanger in automaticity and conduction in sinoatrial node, atrium and atrioventricular node. Our findings support a functional role of sodium–calcium exchanger in human atrial and atrioventricular nodal conduction as suggested by genetically modified mouse models.
Left ventricular hypertrophy (LVH) represents a common final pathway leading to heart failure. We have searched for genetic determinants of left ventricular (LV) mass using values for absolute electrocardiographic QRS voltage in a healthy Japanese population. After adjusting for covariates, the corrected S and R wave voltages in leads V1 and V5 from 2,994 healthy volunteers in the Japan Pharmacogenomics Data Science Consortium (JPDSC) database were subjected to a genome-wide association study. Potential associations were validated by an in silico replication study using an independent Japanese population obtained from the Nagahama Prospective Genome Cohort for Comprehensive Human Bioscience. We identified a novel association between the lead V5, R wave voltage in Japanese individuals and SNP rs7301743[G], which maps near the gene encoding T-box transcription factor Tbx3. Meta-analysis of two independent Japanese datasets demonstrated a marginally significant association of SNP rs7301743 in TBX3|MED13L with a 0.071 mV (95% CI, 0.038–0.11 mV) shorter R wave amplitude in the V5 lead per minor allele copy (P = 7.635 x 10−8). The transcriptional repressor, TBX3, is proposed to suppress the development of working ventricular myocardium. Our findings suggest that genetic variation of Tbx3 is associated with LV mass in a healthy Japanese population.
