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The main aim of this study was to screen epigenetic modifier genes and known breast cancer driver genes for germline mutations in non-BRCA1/2 (BRCAx) breast cancer families in order to identify novel susceptibility genes of moderate–high penetrance. We screened 264 candidate susceptibility genes in 656 index cases from non-BRCA1/2 families. Potentially pathogenic candidate mutations were then genotyped in all available family members for the assessment of co-segregation of the variant with disease in the family in order to estimate the breast cancer risks associated with these mutations. For 11 of the candidate susceptibility genes, we screened an additional 800 non-BRCA1/2 breast cancer cases and 787 controls. Only two genes, CHD8 and USH2A showed any evidence of an increased risk of breast cancer (RR = 2.40 (95% CI 1.0–7.32) and 2.48 (95% CI 1.11–6.67), respectively). We found no convincing evidence that epigenetic modifier and known breast cancer driver genes carry germline mutations that increase breast cancer risk. USH2A is no longer regarded as a breast cancer driver gene and seems an implausible candidate given its association with Usher syndrome. However, somatic mutations in CHD8 have been recently reported, making it an even more promising candidate, but further analysis of CHD8 in very large cohorts of families or case–control studies would be required to determine if it is a moderate-risk breast cancer susceptibility gene.

Background: Systemic lupus erythematosus (SLE) is characterised by dysregulation of autoreactive lymphocytes and antigen-presenting cells. Signalling through Toll-like receptor 9 (TLR9), a mediator of innate immune responses, has a role in activation of dendritic cells and autoreactive B cells. Objective: To investigate whether TLR9 polymorphisms are associated with an increased risk of SLE. Methods: DNA samples were obtained from 220 Japanese patients with SLE (with >4 American College of Rheumatology criteria for SLE) and 203 controls. The genetic variations of TLR9 were detected by PCR, followed by DNA sequencing. The promoter and enhancer activities of TLR9 were measured by luciferase reporter gene assay. The titres of anti-dsDNA antibodies in sera from control or TLR9-deficient mice were analysed by ELISA. Results: The G allele at position +1174 (located in intron 1 of TLR9) is closely associated with an increased risk of SLE (p = 0.029). Furthermore, patients with SLE tend to have C allele at position −1486 (p = 0.11). Both alleles down regulate TLR9 expression by reporter gene assay. TLR9-deficient mice under a C57BL/6 background possess higher titres of anti-dsDNA serum antibodies than control C57BL/6 mice. Conclusions: These results indicate that the presence of the G allele at position +1174 of TLR9 predisposes humans to an increased risk of SLE. It is speculated that TLR9 normally prevents the development of human SLE.

Gitelman syndrome (GS) is a renal tubular disorder characterized by hypokalemia, hypomagnesemia, metabolic alkalosis and hypocalciuria due to defective tubular reabsorption of magnesium and potassium. This disease is caused by mutations of the thiazide-sensitive Na-Cl cotransporter (NCCT) gene, SLC12A3. Manifestations of GS are heterogeneous, from asymptomatic to mild symptoms of cramps and easy fatigue, to tetany and paralysis. Polydipsia, polyuria, and nocturia are also frequent in GS patients. Here we describe two Japanese patients with GS followed as nocturnal enuresis. In the first patient, occasional muscle cramps, easy fatigue and headache led to the diagnosis of GS. The parents of this patient reported that he had been affected by polydipsia and polyuria, especially nocturnal enuresis from early childhood. The second patient was referred to our clinic because of muscular weakness and cramps. He had a past history of transient muscle weakness and muscle cramps. He had also suffered from nocturnal enuresis since 3 yr of age. Laboratory findings of these patients were consistent with those of GS. Sequencing analysis of the SLC12A3 gene from two patients showed four mutations, which were previously reported. In our two patients, their manifestations had been underestimated and the correct diagnosis was delayed. GS is generally likely to be benign, however signs of GS are found in early childhood. Especially, we must recognize that nocturnal enuresis is frequent in symptoms of GS.

Approximately half of the familial aggregation of breast cancer remains unexplained. A multiple-case breast cancer family exome-sequencing study identified three likely pathogenic mutations in RINT1 (NM_021930.4) not present in public sequencing databases: RINT1 c.343C>T (p.Q115X), c.1132_1134del (p.M378del), and c.1207G>T (p.D403Y). On the basis of this finding, a population-based case–control mutation-screening study was conducted that identified 29 carriers of rare (minor allele frequency < 0.5%), likely pathogenic variants: 23 in 1,313 early-onset breast cancer cases and six in 1,123 frequency-matched controls [OR, 3.24; 95% confidence interval (CI), 1.29–8.17; P = 0.013]. RINT1 mutation screening of probands from 798 multiple-case breast cancer families identified four additional carriers of rare genetic variants. Analysis of the incidence of first primary cancers in families of women carrying RINT1 mutations estimated that carriers were at increased risk of Lynch syndrome–spectrum cancers [standardized incidence ratio (SIR), 3.35; 95% CI, 1.7–6.0; P = 0.005], particularly for relatives diagnosed with cancer under the age of 60 years (SIR, 10.9; 95% CI, 4.7–21; P = 0.0003). Significance: The work described in this study adds RINT1 to the growing list of genes in which rare sequence variants are associated with intermediate levels of breast cancer risk. Given that RINT1 is also associated with a spectrum of cancers with mismatch repair defects, these findings have clinical applications and raise interesting biological questions. Cancer Discov; 4(7); 804–15. ©2014 AACR. See related commentary by Ngeow and Eng, p. 762 This article is highlighted in the In This Issue feature, p. 745

Objective:The primary aim of this study was to investigate the association of polymorphisms of TRAF1-C5, a newly identified rheumatoid arthritis (RA) risk locus in Caucasians, with susceptibility to RA and systemic lupus erythematosus (SLE) in Japanese populations. Gene expression levels of TRAF1 and C5 to assess the functional significance of genotypes were also analysed.Methods:A multicentre association study consisting of 4 RA case-control series (4397 cases and 2857 controls) and 3 SLE case-control series (591 cases and 2199 shared controls) was conducted. Genotyping was performed using TaqMan genotyping assay for two single nucleotide polymorphisms (SNPs) that showed the best evidence of association in the previous Caucasian studies. Quantifications of TRAF1 and C5 expression were performed with TaqMan expression assay.Results:Significant differences in allele frequency for both SNPs were observed between RA and control subjects (combined odds ratio = 1.09), while no significant difference was detected between patients with SLE and controls. Interestingly, alleles rs3761847 A and rs10818488 G had increased the risk for RA in the present study, while they decreased the risk in the original studies. A significant difference was found between risk allele carriers and non-carriers of rs10818488 for the expression level of TRAF1 in phorbol myristate acetate-stimulated lymphoblastoid cell lines (p = 0.04).Conclusion:Association of TRAF1-C5 locus with RA susceptibility was detected in the Japanese populations with modest magnitude, while no significant association was observed for SLE. Significant positive effect of genotype on the expression of TRAF1 might support the genetic association between TRAF1 and RA.

Objective STAT4 encodes a transcriptional factor that transmits signals induced by several key cytokines, and it might be a key molecule in the development of autoimmune diseases. Recently, a STAT4 haplotype was reported to be associated with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) in Caucasian populations. This was replicated in a Korean RA population. Interestingly, the degree of risk of RA susceptibility with the STAT4 haplotype was similar in the Caucasian and Korean populations. The present study was undertaken to investigate the effect of STAT4 on susceptibility to RA and SLE in the Japanese. Methods We performed an association study using 3 independent Japanese RA case–control populations (total 3,567 cases and 2,199 controls) and 3 independent Japanese SLE populations (total 591 cases). All samples were genotyped using the TaqMan fluorogenic 5′ nuclease assay for single-nucleotide polymorphism (SNP) rs7574865, which tags the susceptibility haplotype. The association of the SNP with disease susceptibility in each case–control study was calculated using Fisher's exact test, and the results were combined, using the Mantel-Haenszel method, to obtain combined odds ratios (ORs). Results We observed a significant association of the STAT4 polymorphism with susceptibility to both RA and SLE. The combined ORs for RA and SLE, respectively, were 1.27 (P = 8.4 × 10−9) and 1.61 (P = 2.1 × 10−11) for allele frequency distribution; these ORs were quite similar to those previously observed in the Caucasian population. Conclusion We conclude that STAT4 is associated with RA and SLE in the Japanese. Our results indicate that STAT4 is a common genetic risk factor for autoimmune diseases, with similar strength across major racial groups.