An update and frequency distribution of Y chromosome haplogroups in modern Japanese males.

Japanese males belong to the Y chromosome C1a1, C2, D1a2a, D1a2a-12f2b, O1b2, O1b2a1a1, O2a2b1, and O2a1b haplogroups. Notably, the regional frequency of each haplogroup is homogeneous. Owing to recent developments in genome sequencing technology, the phylogenetic tree of Y chromosome haplogroups is updated annually. Therefore, in this study, we aimed to provide an update on the Y chromosome haplogroups of modern Japanese males and examine their regional distributions. Using 1,640 samples of Japanese males from seven Japanese cities (Nagasaki, Fukuoka, Tokushima, Osaka, Kanazawa, Kawasaki, and Sapporo), haplogroups C1a1, C2, D1a2a, D1a2a-12f2b, O1b2, and O1b2a1a1 were updated based on the latest phylogenetic tree. Haplogroup C1a1 was mainly classified into C1a1a1a and C1a1a1b subgroups; C1a1a1b was more common in Tokushima and Osaka than in the other regions. Haplogroup C2 was mainly classified into C2a, C2b1a1a, C2b1a1b, C2b1a2, and C2b1b subgroups and exhibited frequency differences in Osaka. Haplogroup D1a2a was classified into D1a2a1c1 and D1a2a2 subgroups, and its frequency varied between Tokushima and Osaka. Haplogroup D1a2a-12f2b was classified into D1a2a1a2b1a1a and D1a2a1a3 subgroups; however, no significant frequency differences were observed. Haplogroup O1b2 was classified into O1b2a1a2a1a, O1b2a1a2a1b, and O1b2a1a3 subgroups, with frequency differences between Nagasaki and Kanazawa. Haplogroup O1b2a1a1 was mainly classified into O1b2a1a1a, O1b2a1a1b, and O1b2a1a1c subgroups; however, no significant frequency differences were observed. Our findings suggest that gene flow in the Kinki region is caused by human migration.

A machine learning model using SNPs obtained from a genome-wide association study predicts the onset of vincristine-induced peripheral neuropathy.

Vincristine treatment may cause peripheral neuropathy. In this study, we identified the genes associated with the development of peripheral neuropathy due to vincristine therapy using a genome-wide association study (GWAS) and constructed a predictive model for the development of peripheral neuropathy using genetic information-based machine learning. The study included 72 patients admitted to the Department of Hematology, Tokushima University Hospital, who received vincristine. Of these, 56 were genotyped using the Illumina Asian Screening Array-24 Kit, and a GWAS for the onset of peripheral neuropathy caused by vincristine was conducted. Using Sanger sequencing for 16 validation samples, the top three single nucleotide polymorphisms (SNPs) associated with the onset of peripheral neuropathy were determined. Machine learning was performed using the statistical software R package "caret". The 56 GWAS and 16 validation samples were used as the training and test sets, respectively. Predictive models were constructed using random forest, support vector machine, naive Bayes, and neural network algorithms. According to the GWAS, rs2110179, rs7126100, and rs2076549 were associated with the development of peripheral neuropathy on vincristine administration. Machine learning was performed using these three SNPs to construct a prediction model. A high accuracy of 93.8% was obtained with the support vector machine and neural network using rs2110179 and rs2076549. Thus, peripheral neuropathy development due to vincristine therapy can be effectively predicted by a machine learning prediction model using SNPs associated with it.

A Genome-Wide Association Study Predicts the Onset of Dysgeusia Due to Anti-cancer Drug Treatment.

Dysgeusia is a major side effect of anti-cancer drug treatment. Since dysgeusia significantly lowers the patient's QOL, predicting and avoiding its onset in advance is desirable. Accordingly, aims of the present study were to use a genome-wide association study (GWAS) to identify genes associated with the development of dysgeusia in patients taking anti-cancer drugs and to predict the development of dysgeusia using associated single nucleotide polymorphisms (SNPs). GWAS was conducted on 76 patients admitted to the Department of Hematology, Tokushima University Hospital. Using Sanger sequencing for 23 separately collected validation samples, the top two SNPs associated with the development of dysgeusia were determined. GWAS identified rs73049478 and rs41396146 SNPs on the retinoic acid receptor beta (RARB) gene associated with dysgeusia development due to the administration of anti-cancer drugs. Evaluation of the two SNPs using 23 validation samples indicated that the accuracy rate of rs73049478 was relatively high (87.0%). Thus, the findings of the present study suggest that the rs73049478 SNP of RARB can be used to predict the onset of dysgeusia caused by the administration of anti-cancer drugs.

Lrriq1 is an essential factor for fertility by suppressing apoptosis.

PURPOSE: Leucine-rich repeats and IQ motif containing 1 (LRRIQ1) gene is reportedly associated with plasma inhibin B levels. However, the function of LRRIQ1 remains unknown. In this study, we generated Lrriq1 knockout mice (Lrriq1-/- mice) and examined the effects of LRRIQ1 on inhibin B and fertility. METHODS: Lrriq1-/- mice were generated using CRISPR/Cas9 genome editing technology. The expression of Inhibin B was examined by Western blotting using a protein extracted from the testis of a 3-month-old male mouse. Mating experiments were conducted using 7-week-old Lrriq1-/- mice and wild-type (WT) mice to examine fertility. Sperm concentration and sperm motility were measured using 3-month-old male mice. RESULTS: Expression analysis of inhibin B revealed that Lrriq1-/- mice exhibited reduced mRNA and protein levels of inhibin alpha (Inha), which constitutes the α subunit. In the mating experiment, the litter size of Lrriq1-/- male mice was 4.3 ± 2.9, which was significantly lower than that of WT male mice (8.3 ± 1.3) (p < 0.001). No difference in sperm count was observed between Lrriq1-/- and WT male mice; however, sperm motility (%) was significantly reduced in Lrriq1-/- mice (48.4 ± 4.9) when compared with WT mice (70.2 ± 4.7) (p < 0.001). Based on TUNEL staining, the testes and epididymal sperm of Lrriq1-/- mice showed high numbers of apoptosis-positive cells. CONCLUSION: Lrriq1 knockout reduced sperm motility and litter size by inducing apoptosis of testicular germ cells and epididymal sperm.

Genome-wide association study of semen volume, sperm concentration, testis size, and plasma inhibin B levels.

Semen quality is affected by environmental factors, endocrine function abnormalities, and genetic factors. A GWAS recently identified ERBB4 at 2q34 as a genetic locus associated with sperm motility. However, GWASs for human semen volume and sperm concentration have not been conducted. In addition, testis size also reportedly correlates with semen quality, and it is important to identify genes that affect testis size. Reproductive hormones also play an important role in spermatogenesis. To date, genetic loci associated with plasma testosterone, sex hormone-binding globulin (SHBG), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) levels have been identified using GWASs. However, GWASs have not identified any relevant loci for plasma inhibin B levels. We conducted a two-stage GWAS using 811 Japanese men in a discovery stage followed by a replication stage using an additional 721 Japanese men. The results of the discovery and replication stages were combined into a meta-analysis. After setting a suggestive significance threshold for P values < 5 × 10-6　in the discovery stage, we identified ten regions with SNPs (semen volume: one, sperm concentration: three, testes size: two, and inhibin B: four). We selected only the most significant SNP in each region for replication genotyping. Combined discovery and replication results in the meta-analysis showed that the locus 12q21.31 associated with plasma inhibin B levels (rs11116724) had the most significant association (P = 5.7 × 10-8). The LRRIQ1 and TSPAN19 genes are located in the 12q21.31 region. This study provides new susceptibility variants that contribute to plasma inhibin B levels.

Genome-wide association study identifies ERBB4 on 2q34 as a novel locus associated with sperm motility in Japanese men.

BACKGROUND: The decrease in sperm motility has a potent influence on fertilisation. Sperm motility, represented as the percentage of motile sperm in ejaculated sperms, is influenced by lifestyle habits or environmental factors and by inherited factors. However, genetic factors contributing to individual differences in sperm motility remain unclear. To identify genetic factors that influence human sperm motility, we performed a genome-wide association study (GWAS) of sperm motility. METHODS: A two-stage GWAS was conducted using 811 Japanese men in a discovery stage, followed by a replication study using an additional 779 Japanese men. RESULTS: In the two-staged GWAS, a single nucleotide polymorphism rs3791686 in the intron of gene for erb-b2 receptor tyrosine kinase 4 (ERBB4) on chromosome 2q34 was identified as a novel locus for sperm motility, as evident from the discovery and replication results using meta-analysis (ß=-4.01, combined P=5.40×10-9). CONCLUSIONS: Together with the previous evidence that Sertoli cell-specific Erbb4-knockout mice display an impaired ability to produce motile sperm, this finding provides the first genetic evidence for further investigation of the genome-wide significant association at the ERBB4 locus in larger studies across diverse human populations.

Association of TUSC1 and DPF3 gene polymorphisms with male infertility.

PURPOSE: Recently, genome-wide association studies of a Hutterite population in the USA revealed that five single nucleotide polymorphisms (SNPs) with a significant association with sperm quality and/or function in ethnically diverse men from Chicago were significantly correlated with family size. Of these, three SNPs (rs7867029, rs7174015, and rs12870438) were found to be significantly associated with the risk of azoospermia and/or oligozoospermia in a Japanese population. In this study, we investigated whether the rs10966811 (located in an intergenic region between the TUSC1 and IZUMO3 genes) and rs10129954 (located in the DPF3 gene) SNPs, previously related to family size, are associated with male infertility. In addition, we performed association analysis between rs12348 in TUSC1 and rs2772579 in IZUMO3 and male infertility. METHODS: We genotyped 145 patients with infertility (including 83 patients with azoospermia and 62 with oligozoospermia) and 713 fertile controls by PCR-RFLP technique for polymorphism. Because rs10966811 has no restriction sites, the SNP rs12376894 with strong linkage disequilibrium was selected as an alternative to rs10966811. RESULTS: There was a statistically significant association between rs12376894 proxy SNP of rs10966811 and oligozoospermia. Also, a statistically significant association between rs10129954 and azoospermia, and oligozoospermia was observed. When we assessed the relationship between rs12348 in TUSC1 and rs2772579 in IZUMO3 and male infertility traits, we found that rs12348 in TUSC1 was significantly associated with azoospermia and oligozoospermia, but rs2772579 in IZUMO3 was not associated with male infertility. CONCLUSION: We found that the polymorphisms in TUSC1 and DPF3 displayed strong associations with male infertility.

A replication study of a candidate locus for follicle-stimulating hormone levels and association analysis for semen quality traits in Japanese men.

In men, follicle-stimulating hormone (FSH) acts on the seminiferous tubules and enhances spermatogenesis. Recently, a candidate locus (rs2414095) for FSH levels was identified by a genome-wide association study (GWAS) in Chinese men. The rs2414095 single-nucleotide polymorphism (SNP) is found on the third intron of the cytochrome P450, family 19, subfamily A, peptide 1 (CYP19A1) gene encoding an aromatase. In the present study, we performed a replication study in 1687 Japanese men (901 from cohort 1 and 786 from cohort 2) to assess whether this SNP is associated with circulating FSH levels. Furthermore, we investigated whether the rs2414095 SNP is correlated with semen quality traits in 2015 Japanese men (1224 from cohort 1 and 791 from cohort 2). The rs2414095 SNP was significantly associated with circulating FSH levels (ßSTD=0.15, P=9.7 × 10-5), sperm concentration (ßSTD=0.073, P=0.032) and total sperm number (TSN) (ßSTD=0.074, P=0.027) in a combined analysis of the two Japanese male cohorts. We successfully replicated, in Japanese men, the results of the previous GWAS for the rs2414095 SNP in Chinese men, and found that the rs2414095 SNP was related with sperm production.

Labelling of endogenous target protein via N-S acyl transfer-mediated activation of N-sulfanylethylanilide.

The ligand-dependent incorporation of a reporter molecule (e.g., fluorescence dye or biotin) onto a endogenous target protein has emerged as an important strategy for elucidating protein function using various affinity-based labelling reagents consisting of reporter, ligand and reactive units. Conventional labelling reagents generally use a weakly activated reactive unit, which can result in the non-specific labelling of proteins in a ligand-independent manner. In this context, the activation of a labelling reagent through a targeted protein-ligand interaction could potentially overcome the problems associated with conventional affinity-based labelling reagents. We hypothesized that this type of protein-ligand-interaction-mediated activation could be accomplished using N-sulfanylethylanilide (SEAlide) as the reactive unit in the labelling reagent. Electrophilically unreactive amide-type SEAlide can be activated by its conversion to the corresponding active thioester in the presence of a phosphate salt, which can act as an acid-base catalyst. It has been suggested that protein surfaces consisting of hydrophilic residues such as amino, carboxyl and imidazole groups could function as acid-base catalysts. We therefore envisioned that a SEAlide-based labelling reagent (SEAL) bearing SEAlide as a reactive unit could be activated through the binding of the SEAL with a target protein. Several SEALs were readily prepared in this study using standard 9-fluorenylmethyloxycarbonyl (Fmoc)-based solid-phase protocols. These SEAL systems were subsequently applied to the ligand-dependent labelling of human carbonic anhydrase (hCA) and cyclooxyganese 1. Although we have not yet obtained any direct evidence for the target protein-mediated activation of the SEAlide unit, our results for the reaction of these SEALs with hCA1 or butylamine indirectly support our hypothesis. The SEALs reported in this study represent valuable new entries to the field of affinity-based labelling reagents and are expected to show great utility in protein labelling.

An association study of four candidate loci for human male fertility traits with male infertility.

STUDY QUESTION: Are the four candidate loci (rs7867029, rs7174015, rs12870438 and rs724078) for human male fertility traits, identified in a genome-wide association study (GWAS) of a Hutterite population in the USA, associated with male infertility in a Japanese population? SUMMARY ANSWER: rs7867029, rs7174015 and rs12870438 are significantly associated with the risk of male infertility in a Japanese population. WHAT IS KNOWN ALREADY: Recently, a GWAS of a Hutterite population in the USA revealed that 41 single-nucleotide polymorphisms (SNPs) were significantly correlated with family size or birth rate. Of these, four SNPs (rs7867029, rs7174015, rs12870438 and rs724078) were found to be associated with semen parameters in ethnically diverse men from Chicago. STUDY DESIGN, SIZE, DURATION: This is a case-control association study in a total of 917 Japanese subjects, including 791 fertile men, 76 patients with azoospermia and 50 patients with oligozoospermia. PARTICIPANTS/MATERIALS, SETTING, METHODS: Azoospermia was diagnosed on the basis of semen analysis (the absence of sperm in ejaculate), serum hormone levels and physical examinations. Oligozoospermia was defined as a sperm concentration of <20 × 10(6)/ml. We excluded patients with any known cause of infertility (i.e. obstructive azoospermia, varicocele, cryptorchidism, hypogonadotropic hypogonadism, karyotype abnormalities or complete deletion of AZF a, b or c). The SNPs rs7867029, rs7174015, rs12870438 and rs724078 were genotyped using DNA from peripheral blood samples and either restriction fragment length polymorphism PCR or TaqMan probes. Genetic associations between the four SNPs and male infertility were assessed using a logistic regression analysis under three different comparative models (additive, recessive or dominant). MAIN RESULTS AND THE ROLE OF CHANCE: The genotypes of all four SNPs were in Hardy-Weinberg equilibrium in the fertile controls. The SNPs rs7867029 and rs7174015 are associated with oligozoospermia [rs7867029: odds ratio (OR) = 1.70, 95% confidence interval (CI) = 1.07-2.68, P = 0.024 (log-additive); rs7174015: OR = 6.52, 95% CI = 1.57-27.10, P = 0.0099 (dominant)] and rs12870438 is associated with azoospermia (OR = 10.90, 95% CI = 2.67-44.60, P = 0.00087 (recessive)] and oligozoospermia [OR = 8.54, 95% CI = 1.52-47.90, P = 0.015 (recessive)]. The association between rs7174015 and oligozoospermia under a dominant model and between rs12870438 and azoospermia under additive and recessive models remained after correction for multiple testing. There were no associations between rs724078 and azoospermia or oligozoospermia. LIMITATIONS, REASONS FOR CAUTION: Even though the sample size of case subjects was not very large, we found that three SNPs were associated with the risk of male infertility in a Japanese population. WIDER IMPLICATIONS OF THE FINDINGS: The three infertility-associated SNPs may be contributing to a quantitative reduction in spermatogenesis. STUDY FUNDING/COMPETING INTERESTS: This study was supported in part by the Ministry of Health and Welfare of Japan (1013201) (to T.I.), Grant-in-Aids for Scientific Research (C) (23510242) (to A.Ta.) from the Japan Society for the Promotion of Science, the European Union (BMH4-CT96-0314) (to T. I.) and the Takeda Science Foundation (to A.Ta.). None of the authors has any competing interests to declare.

Lack of replication of four candidate SNPs implicated in human male fertility traits: a large-scale population-based study.

STUDY QUESTION: Are the four candidate loci (rs7867029, rs12870438, rs7174015 and rs724078) for human male fertility traits, identified in a genome-wide association study (GWAS) of a Hutterite population in the USA, associated with semen quality traits in a Japanese population? SUMMARY ANSWER: The four single nucleotide polymorphisms (SNPs) rs7867029, rs12870438, rs7174015 and rs724078 have no association with semen parameters in a meta-analysis of two Japanese male cohorts. WHAT IS KNOWN ALREADY: Four (rs7867029, rs12870438, rs7174015 and rs724078) of the SNPs associated with family size or birth rate in the GWAS of a Hutterite population in the USA were associated with semen parameters in ethnically diverse men from Chicago, USA. STUDY DESIGN, SIZE, DURATION: This is a replication study in a total of 2015 Japanese subjects, including 791 fertile men and 1224 young men from the general population. PARTICIPANTS/MATERIALS, SETTING, METHODS: We performed a replication study in two cohorts to assess whether the SNPs rs7867029, rs12870438, rs7174015 and rs724078 are associated with sperm concentration, semen volume, total sperm numbers, total motile sperm numbers or sperm motility. The rs12870438 SNP was detected by restriction fragment length polymorphism PCR while rs7174015, rs724078 and rs7867029 SNPs were genotyped using TaqMan probes. MAIN RESULTS AND THE ROLE OF CHANCE: This study indicated that none of the four SNPs rs7867029, rs12870438, rs7174015 and rs724078 displayed a significant association with semen parameters in the meta-analysis of two Japanese male cohorts. LIMITATIONS, REASONS FOR CAUTION: Only four SNPs identified in the Hutterite GWAS were examined for associations with semen quality traits in a Japanese population. In addition, the linkage disequilibrium structures around the testing markers were different between ethnic groups. WIDER IMPLICATIONS OF THE FINDINGS: Locus mapping studies using a set of tagging SNPs across the loci will be necessary in populations with larger sample sizes in order to understand the contribution of specific genes to semen quality. STUDY FUNDING/COMPETING INTEREST S: This study was supported in part by the Ministry of Health and Welfare of Japan (1013201) (to T.I.), Grant-in-Aids for Scientific Research (C) (23510242) (to A.Ta.) from the Japan Society for the Promotion of Science, the European Union (BMH4-CT96-0314) (to T.I.), and the Takeda Science Foundation (to A.Ta.). None of the authors has any competing interests to declare.

Y chromosome gr/gr subdeletion is associated with lower semen quality in young men from the general Japanese population but not in fertile Japanese Men.

Several case-control studies have investigated whether Y chromosome haplogroups or deletions are associated with spermatogenic failure. However, the relationships between Y chromosome haplogroups or deletions and semen quality in general population have not been elucidated. In this study, we assessed relationships between Y chromosome haplogroups or deletions and semen parameters in 791 fertile Japanese men and 1221 young men from the general Japanese population. We found that the haplogroup D2 (M55 lineage) was significantly associated with lower semen parameters, especially total motile sperm count (P = 0.00051, beta = -0.097), in men from the general population but not in fertile men. In addition, we found that the gr/gr subdeletion was associated with semen quality and in particular, strongly associated with decreased sperm motility (P = 0.00041, beta = -3.14) and total motile sperm count (P = 0.00031, beta = -0.099) in men from the general population but not in fertile men. The combined analysis of fertile Japanese men and men from the general Japanese population showed that the haplogroup D2 (M55 lineage) and the gr/gr subdeletion were strongly associated with reduced sperm motility (P = 0.00056, beta = -2.71, and P = 7.7 × 10(-5), beta = -3.05, respectively) and that haplogroup O2b1 was strongly associated with elevated sperm motility (P = 0.00089, beta = 2.94). These observations add further support for the view that the gr/gr subdeletion diminishes sperm motility that consequently may result in male infertility.

Development of a traceable linker containing a thiol-responsive amino acid for the enrichment and selective labelling of target proteins.

A traceable linker that is potentially applicable to identification of a target protein of bioactive compounds was developed. It enabled not only thiol-induced cleavage of the linker for enrichment of the target protein but also selective labelling to pick out the target from contaminated non-target proteins for facile identification.

A meta-analysis of the association of PPARγ rs1801282 polymorphism and NSAID usage with the risk of developing cancer.

Use of nonsteroidal anti-inflammatory drugs (NSAIDs) is correlated with a reduced risk of cancer through the reduction of inflammation, which is an important risk factor. Several studies have investigated polymorphisms in the peroxisome proliferator-activated receptor gamma (PPARγ) gene and NSAID use in association with cancer risk. However, these studies yielded mixed results. Therefore, we performed a meta-analysis to evaluate the association of PPARγ polymorphisms and NSAID usage with cancer risk. We conducted a comprehensive search of PubMed through May 2013. Odds ratios (ORs) with corresponding 95% confidence intervals (CIs) were calculated using the fixed-effect or random-effect model. A comprehensive search of the database revealed 6 studies that fulfilled the inclusion criteria. NSAID use was significantly associated with decreased cancer risk regardless of PPARγ rs1801282 genotypes. In a stratified analysis by cancer type, NSAID users who were minor allele carriers had significantly decreased colon cancer risk compared to non-NSAID users (OR=0.73, 95% CI=0.57-0.93), whereas NSAID users homozygous for the major allele had significantly decreased risk for cancers other than colon cancer compared to non-NSAID users (OR=0.79, 95% CI=0.69-0.91). Our results suggest that the association of PPARγ rs1801282 polymorphism and NSAID use with the risk of cancer may differ according to cancer type.

Y chromosome haplogroups are associated with birth size in Japanese men.

The Y chromosome is classified into haplogroups (A-T) based on a combination of several DNA polymorphisms. Japanese men are mainly classified into haplogroups C, D, and O, which have been further subdivided. The distribution of Y-chromosome haplogroups varies by ethnicity. The phylogenetic age, origin, and migration also differ. I hypothesized that Y chromosome haplogroups may be associated with height and/or weight at birth. An association analysis of height and weight at birth with Y chromosome haplogroups was performed in 288 Japanese men. Men belonging to haplogroup O1b2 were significantly associated with short stature at birth (beta = －1.88, standard error (SE) = 0.55, P = 0.00076), and those belonging to D1a2a-12f2b were significantly associated with increased birth weight (beta = 174, SE = 64, P = 0.0069). Y chromosome haplogroups are associated with physical birth characteristics in modern Japanese men. J. Med. Invest. 71 : 129-133, February, 2024.

Study on prediction of early adverse events by CapeOX therapy in patients with colorectal cancer.

CapeOX is a regimen used as postoperative adjuvant chemotherapy for the treatment of advanced recurrent colorectal cancer. If early adverse events occur, treatment may not progress as planned and further dose reduction may be necessary. In this study, we investigated whether pre-treatment medical records could be used to predict adverse events in order to prevent adverse events caused by CapeOX treatment. The 178 patients were classified into two groups (97 in the adverse event positive group and 81 in the adverse event-negative group) based on withdrawal or postponement of four or fewer courses. In univariate analysis, age, height, weight, body surface area (BSA), creatinine clearance, muscle mass, and lean body mass were associated with early adverse events (P<0.05). The area under the receiver operating characteristic curve obtained by Stepwise logistic regression analysis using the Akaike information criterion method was 0.832. For nested k-fold cross validation, the accuracy rates of the support vector machine, random forest, and logistic regression algorithms were 0.71, 0.70, and 0.75, respectively. The results of the present study suggest that a logistic regression prediction model may be useful in predicting early adverse events caused by CapeOX therapy in patients with colorectal cancer. J. Med. Invest. 71 : 141-147, February, 2024.

Y chromosome haplogroup d2* lineage is associated with azoospermia in Japanese males.

Several studies have investigated whether particular Y chromosome haplogroups are associated with spermatogenic failure in Japanese males; however, they produced differing results. In this study, to investigate the association of Y chromosome haplogroup with spermatogenic failure, we recruited 451 infertile patients and 730 fertile men from a Japanese population and typed their Y chromosome haplogroups. The infertile patients were suffering from varicocele, azoospermia, oligozoospermia, asthenozoospermia, obstructive azoospermia, karyotype abnormalities, microdeletions of the long arm of the Y chromosome, or other conditions that affect fertility. The frequency of haplogroup D2* was significantly higher (odds ratio = 2.28, 95% confidence interval = 1.44-3.61, P = 0.00034 using chi-square test) among the men with azoospermia than among the fertile men. None of the other Y haplogroups displayed associations with particular types of infertility. In conclusion, Y chromosome haplogroup D2* is associated with spermatogenic failure in Japanese males, suggesting that the Y chromosome lineage can have significant effects on spermatogenesis.

Replication study and meta-analysis of human nonobstructive azoospermia in Japanese populations.

Recently, a Chinese genomewide association study (GWAS) identified four autosomal single-nucleotide polymorphism (SNP) loci as being significantly associated with risk factors for nonobstructive azoospermia (NOA; P < 5 × 10(-8)). In the present study, we performed a replication study on two Japanese cohorts from different institutions in order to evaluate whether SNP loci are associated with NOA. The four SNPs (rs12097821, rs2477686, rs10842262, and rs6080550) reported in the Chinese GWAS were genotyped in 490 NOA patients and 1167 controls. To assess the significance of the associations between each of the four SNPs and NOA in the Japanese population, the association results for the two cohorts were combined by meta-analysis. In the meta-analysis, the combined per-allele odds ratios (ORs) for the four SNPs and their respective 95% confidence intervals (CIs) were as follows: rs12097821, OR = 1.10 (CI = 0.89-1.37); rs2477686, OR = 1.11 (CI = 0.87-1.43); rs10842262, OR = 1.11 (CI = 0.94-1.32); and rs6080550, OR = 0.96 (CI = 0.76-1.21). None of the SNPs was significantly associated with NOA (P > 0.05). However, three of four SNPs (rs12097821, rs2477686, and rs10842262) showed associations in the same direction in Japanese men as those reported in the Chinese GWAS. To determine whether the four SNPs are genetic risk factors for NOA, the effect sizes of NOA risk factors require further investigation using larger independent sets of case-control samples of populations, including Japanese and Chinese populations.

Analysis of the correlation between gene copy deletion in the AZFc region and male infertility in Japanese men.

Deletion of the azoospermia factor c (AZFc), located on the long arm of the Y chromosome, is a cause of male infertility. The structure of the Y chromosome is diversified by the copy number of various genes, such as deleted in azoospermia (DAZ), basic protein Y2, chromodomain Y1, testis-specific transcript Y-linked 4, and Golgi autoantigen golgin subfamily a2 like Y, located in the AZF region. In this study, we investigated the deletion of each gene copy and analyzed its relationship with Japanese male infertility. Deletions of single nucleotide variants of each gene copy in 721 proven fertile men as controls, 139 patients with non-obstructive azoospermia (NOA), and 56 patients with oligozoospermia (OS) were analyzed via polymerase chain reaction-restriction fragment length polymorphism analysis. Their association with infertility was analyzed using logistic regression analysis adjusted for the Y-chromosome haplogroup, D1a2a. Deletions of DAZ/II in the r1 region and DAZ/V in the r1 and r2 regions showed significant associations with NOA (odds ratio [OR] = 4.15, 95 % confidence interval [CI] = 1.18-14.6, P = 0.026; OR = 4.19, 95 % CI = 1.19-14.7, P = 0.025, respectively). They did not show any association with OS. Partial deletion of the AZFc region affects spermatogenesis in Japanese male.

Climatic influence on the reproductive characteristics of Japanese males.

We previously performed a survey of the sperm characteristics of the partners of pregnant women in four cities in Japan. In the present study, we analyzed the sperm characteristics of these subjects and the correlations between these sperm characteristics and climatic changes or Y chromosome haplogroups. Our results showed that more haplogroup D2a1 males than O2b1 males were born in the first half of the year (January to June), whereas more O2b1 males were born in the last half of the year (July to December) (P<0.05). This was agreed and correlated with the seasonal variations in their mean sperm concentrations. The haplogroup C, D* and D2a1 males displayed lower sperm concentrations from March to May, followed by an increase in their sperm concentrations starting in June or July, while the O2b1 males displayed higher sperm concentrations in the first half of the year followed by a sudden decrease from July to August (P<0.05). We hypothesize that the Japanese climate has different effects on the sperm characteristics and reproductive seasonality of males from different lineages; and therefore, has influenced the modern population of Japan.