Investigating the association between OPA1 polymorphisms and glaucoma: comparison between normal tension and high tension primary open angle glaucoma

OPA1, the gene responsible for autosomal dominant optic atrophy, represents a good candidate gene for glaucoma, as there are similarities in the clinical phenotype and OPA1 is expressed in the optic nerve. Single nucleotide polymorphisms on intervening sequence (IVS) 8 of the OPA1gene (genotype IVS8+4 C/T;+32T/C) were recently found to be strongly associated with normal tension glaucoma (NTG). In order to investigate whether this association exists in patients with high-tension glaucoma (HTG), 90 well-characterized HTG patients were examined for the presence of these OPA1polymorphisms by PCR amplification followed by bi-directional sequencing. Five out of 90 HTG subjects (5.6%; 95% CI 1.8-12.5) were found to carry the OPA1 genotype IVS 8+4 C/T; +32 T/C, compared with 32/163 (19.6%; 95% CI 13.8-26.6) NTG subjects [chi(2)=9.2, P=0.002, OR 4.1 (95% CI 1.6-11.1)], and 7/186 (3.8%; 95% CI 1.5-7.6) control subjects [chi(2)=0.47, P=0.49, OR 1.5 (95% CI 0.5-4.9)]. These results indicate that unlike NTG, the OPA1 genotype IVS8+4 C/T,+32T/C is not significantly associated with high-tension primary open angle glaucoma, and suggest genetic heterogeneity between the conditions.     

Association of OPA1 Polymorphisms with NTG and HTG: A Meta-Analysis

Background

Genetic polymorphisms of the Optic atrophy 1 gene have been implicated in altering the risk of primary open angle glaucoma (POAG), especially the susceptibility to normal tension glaucoma (NTG), but the results remain controversial.

Methods

Multiple electronic databases (up to January 20, 2012) were searched independently by two investigators. A meta-analysis was performed on the association between Optic atrophy 1 polymorphisms (rs 166850 and rs 10451941) and normal tension glaucoma (NTG)/high tension glaucoma (HTG). Summary odds ratios (ORs) and 95% confidence intervals (CI) were estimated.

Results

Seven studies of 713 cases and 964 controls for NTG and five studies of 1200 cases and 971 controls for HTG on IVS8+4C>T (rs 166850) and IVS8+32T>C (rs10451941) were identified. There were significant associations between the OPA1 rs10451941polymorphism and NTG susceptibility for all genetic models(C vs. T OR = 1.26, 95% CI 1.09–1.47, p = 0.002; CC vs. TT: OR = 1.52, 95% CI 1.04–2.20, p = 0.029; CC vs. CT+TT: OR = 1.64, 95% CI 1.16–2.33, p = 0.005; CC+CT vs. TT: OR = 1.21, 95% CI 1.02–1.44, p = 0.032). However, no evidence of associations was detected between the OPA1 IVS8+32C>T polymorphism and POAG susceptibility to HTG. Similarly, clear associations between the rs 166850 variant and NTG were observed in allelic and dominant models (T vs. C OR = 1.52, 95% CI 1.16–1.99, p = 0.002; TT+TC vs. CC OR = 1.50, 95% CI 1.13–2.01, p = 0.006) but not to HTG. In subgroup analyses by ethnicity, we detected an association between both OPA1 polymorphisms and risk for NTG in Caucasians but not in Asians. By contrast, no significant findings were noted between OPA1 variants for HTG, either in Caucasians or in Asians.

Conclusions

Both the IVS8+4C>T and IVS8+32T>C variants may affect individual susceptibility to NTG. Moreover, stratified analyses for NTG detecting the effects of both OPA1 polymorphisms seemed to vary with ethnicity. Further investigations are needed to validate the association.     

Risk Factors for Normal and High-Tension Glaucoma in Poland in Connection with Polymorphisms of the Endothelial Nitric Oxide Synthase Gene

Aim

The purpose of this study was to evaluate the influence of polymorphisms of the eNOS gene on the clinical status of patients with normal and high tension glaucoma.

Methods

266 Polish Caucasian patients with primary open angle glaucoma were studied. Of the 266, 156 had normal tension glaucoma (NTG) and 110 high tension glaucoma (HTG). DNA material was isolated from peripheral venous blood using commercial kits. Real-time PCR reaction was used to amplify the promoter site of the endothelial nitric oxide synthase (eNOS) gene, including the single nucleotide polymorphism (SNP) site T-786C and part of the 7^th exon of eNOS, including G894T SNP. Genotypes were determined with TaqMan SNP Genotyping Assays.

Results

There were no significant differences in frequencies of the allelic variants of both polymorphisms. In G894T SNP, however, the wild GG form was more common in the HTG group. The SNP of the eNOS gene did not significantly influence the progression rate in either of the groups studied. There were no differences in variants of the eNOS gene regarding the necessity for and success of surgery and the progression of the disease. In the NTG group, no statistical correlation was observed between G894T, T786C polymorphism variants, and risk factors such as optic disc haemorrhages, optic disc notches, and peripapillary atrophy. Mean diastolic and systolic pressure during the day and night were lowest in NTG patients with the CC variant of the T786C polymorphism. No statistical correlation was observed between the G894T and T786C polymorphisms and capillaroscopic examination results.

Conclusions

Genotype frequencies are similar for both the eNOS G894T and T-786C polymorphisms in NTG and HTG patients. These polymorphisms do not correlate with risk factors and do not influence the state of the capillary system in NTG patients. Systolic blood pressure is lower in NTG patients with mutated alleles of both polymorphisms.     

Common variants on chromosome 9p21 are associated with normal tension glaucoma

Although intraocular pressure (IOP) is the most definitive cause of glaucoma, a subtype of open angle glaucoma (OAG) termed normal tension glaucoma (NTG), which occurs in spite of normal IOP, accounts for a large part of glaucoma cases, especially in Japan. To find common genetic variants contributing to NTG in Japanese patients, we conducted a genome-wide association study (GWAS). We performed the first screening for 531,009 autosomal SNPs with a discovery cohort of 286 cases and 557 controls, and then a second screening for the top 30 suggestive loci in an independent cohort of 183 cases and 514 controls. Our findings identified a significantly associated SNP; rs523096 [combined p-value = 7.40× 10⁻⁸, odds ratio (OR)  = 2.00 with 95% confidence interval (CI) 1.55–2.58] located 10 kbp upstream of CDKN2B on chromosome 9p21. Moreover, analysis of another independent case-control set successfully replicated the results of the screening studies (combined values of all 3 stages p = 4.96 × 10⁻¹¹, OR  = 2.13 with 95% CI 1.69–2.68). The SNPs near rs523096 were recently reported to be associated with OAG associated with elevated IOP in primary open-angle glaucoma (POAG), the predominant subtype of glaucoma in Caucasian populations. Our results revealed that the 9p21 locus is also associated with NTG in Japanese. In addition, we identified SNPs more strongly associated with NTG.     

High prevalence of SLC6A8 deficiency in X-linked mental retardation

A novel X-linked mental retardation (XLMR) syndrome was recently identified, resulting from creatine deficiency in the brain caused by mutations in the creatine transporter gene, SLC6A8. We have studied the prevalence of SLC6A8 mutations in a panel of 290 patients with nonsyndromic XLMR archived by the European XLMR Consortium. The full-length open reading frame and splice sites of the SLC6A8 gene were investigated by DNA sequence analysis. Six pathogenic mutations, of which five were novel, were identified in a total of 288 patients with XLMR, showing a prevalence of at least 2.1% (6/288). The novel pathogenic mutations are a nonsense mutation (p.Y317X) and four missense mutations. Three missense mutations (p.G87R, p.P390L, and p.P554L) were concluded to be pathogenic on the basis of conservation, segregation, chemical properties of the residues involved, as well as the absence of these and any other missense mutation in 276 controls. For the p.C337W mutation, additional material was available to biochemically prove (i.e., by increased urinary creatine : creatinine ratio) pathogenicity. In addition, we found nine novel polymorphisms (IVS1+26G-->A, IVS7+37G-->A, IVS7+87A-->G, IVS7-35G-->A, IVS12-3C-->T, IVS2+88G-->C, IVS9-36G-->A, IVS12-82G-->C, and p.Y498) that were present in the XLMR panel and/or in the control panel. Two missense variants (p.V629I and p.M560V) that were not highly conserved and were not associated with increased creatine : creatinine ratio, one translational silent variant (p.L472), and 10 intervening sequence variants or untranslated region variants (IVS6+9C-->T, IVS7-151_152delGA, IVS7-99C-->A, IVS8-35G-->A, IVS8+28C-->T, IVS10-18C-->T, IVS11+21G-->A, IVS12+15C-->T, *207G-->C, IVS12+32C-->A) were found only in the XLMR panel but should be considered as unclassified variants or as a polymorphism (p.M560V). Our data indicate that the frequency of SLC6A8 mutations in the XLMR population is close to that of CGG expansions in FMR1, the gene responsible for fragile-X syndrome.     

MSTN genotype (g.66493737C/T) association with speed indices in Thoroughbred racehorses

Sequence variation at the equine myostatin gene (MSTN) locus has previously been shown to have a singular genomic influence on optimum race distance in Thoroughbred racehorses. Myostatin, encoded by the MSTN gene, is a member of the TGF-β superfamily that regulates skeletal muscle development in a range of mammalian species including the horse. In the Thoroughbred, the C-allele at the g.66493737C/T SNP has been found at significantly higher frequency in subgroups of the population that are suited to fast, short distance, sprint races and also influences body composition phenotypes. We investigated the influence of the g.66493737C/T SNP on speed indexes measured in a cohort of n = 85 Thoroughbred horses-in-training. We found significant associations between genotypes at the g.66493737C/T SNP and all measured speed variables: Dist(6) [distance travelled during 6 s before and after maximal velocity (V(max)); P = 0.0040], V(maxt) (duration at V(max); P = 0.0249), V(max) (P = 0.0265), Dist(6b) (distance travelled during 6 s before V(max); P = 0.0032), and Dist(6a)(distance travelled during 6 s after V(max); P = 0.0317). For each measure, horses with the C/C and C/T genotypes outperformed T/T horses, indicating the requirement for at least one C-allele to improve speed. For the most significantly associated variables (Dist(6) and Dist(6b)) the C/C cohort performed better than the T/T cohort with the heterozygotes intermediate, indicating a dose-dependent manifestation. These findings clearly indicate that variation at the MSTN gene influences speed in Thoroughbred horses.     

Association of interleukin-13 SNP rs1800925 with allergic rhinitis risk: A meta-analysis based on 1,411 cases and 3169 controls

Studies investigating the association between interleukin-13 (IL-13) single nucleotide polymorphism (SNP) rs1800925 and allergic rhinitis risk have reported conflicting results. The aim of the present study was to conduct a meta-analysis assessing the possible association of IL-13 SNP rs1800925 with allergic rhinitis risk. The relevant studies were identified through a search of PubMed, Embase, ISI Web of Knowledge and Chinese National Knowledge Infrastructure until December 2011 and selected on the basis of the established inclusion criteria for publications. Five studies were included in the present meta-analysis (1411 cases and 3169 controls). The combined results based on all studies showed that IL-13 SNP rs1800925 was not associated with increased allergic rhinitis risk (T versus C: odds ratio (OR)=1.06, 95% confidence interval (CI)=0.94-1.20; C/T versus C/C: OR=1.12, 95% CI=0.97-1.29; T/T versus C/C: OR=1.00, 95% CI=0.69-1.44; C/T+T/T versus CC: OR=1.10, 95% CI=0.96-1.27; T/T versus C/C+C/T: OR=0.91, 95% CI=0.64-1.31). This meta-analysis supported that IL-13 SNP rs1800925 was not associated with allergic rhinitis.     

Association of HK2 and NCK2 with Normal Tension Glaucoma in the Japanese Population

Although family studies and genome-wide association studies have shown that genetic factors play a role in glaucoma, it has been difficult to identify the specific genetic variants involved. We tested 669 single nucleotide polymorphisms (SNPs) from the region of chromosome 2 that includes the GLC1B glaucoma locus for association with primary open-angle glaucoma (POAG) and normal tension glaucoma (NTG) in the Japanese population. We performed a two-stage case-control study. The first cohort consisted of 123 POAG cases, 121 NTG cases and 120 controls: the second cohort consisted of 187 POAG cases, 286 NTG cases, and 271 controls. Out of six SNPs showing significant association with POAG in the first round screening, seven SNPs were tested in the second round. Rs678350 in the HK2 gene coding sequence showed significant allelic (p = 0.0027 in Stage Two, 2.7XE-4 in meta-analysis) association with POAG, and significant allelic (p = 4.7XE-4 in Stage Two, 1.0XE-5 in meta-analysis) association with NTG. Although alleles in the TMEM182 gene did not show significant association with glaucoma in the second round, subjects with the A/A allele in TMEM182 rs869833 showed worse visual field mean deviation (p = 0.01). Even though rs2033008 in the NCK2 gene coding sequence did not show significant association in the first round, it had previously shown association with NTG so it was tested for association with NTG in round 2 (p = 0.0053 in Stage Two). Immunohistochemistry showed that both HK2 and NCK2 are expressed in the retinal ganglion cell layer. Once multi-testing was taken into account, only HK2 showed significant association with POAG and NTG in Stage Two. Our data also support previous reports of NCK2 association with NTG, and raise questions about what role TMEM182 might play in phenotypic variability. Our data suggest that HK2 may play an important role in NTG in the Japanese population.     

Polymorphism of SLC14A1 encoding human erythrocytic Kidd antigens in the Chinese population

The SLC14A1 gene, which encodes the important Kidd blood group antigens, has not been systematically?analyzed at the molecular level in Chinese individuals. In this study, SLC14A1 genetic polymorphism was examined in Chinese individuals with Jk(a+b-), Jk(a+b+), and Jk(a-b+) expression. The Kidd phenotype was determined for 146 specimens using monoclonal anti-Jk^a and -Jk^b antibodies. From these, 87 specimens were Jk(a-b+), 21 were Jk(a+b-), and 38 were Jk(a+b+). According to the Kidd phenotype results, 20 specimens were randomly selected from each group, i.e., Jk(a-b+), Jk(a+b-), and Jk(a+b+), for the molecular analyses of exons 3 to 11 of the SLC14A1 gene. Novel alleles were detected in the SLC14A1 gene, including IVS3-106A, IVS3-99A, exon3 130G, IVS4-299G, IVS4-293G, IVS4+211C, IVS4 +230C, exon6 499A, exon6 588A, IVS7-68T, IVS9+244G, and IVS10-153T, indicating that the locus harbored significant polymorphism. We also showed that IVS4-299, IVS7-68, and IVS10-153 were novel SNPs absolutely associated with exon 8 nt. 838. The minor allele frequencies were all greater than 10% and all SNPs in the Chinese population showed Vel antigen expression on RBC membranes. We identified 12 SNPs in the SLC14A1 gene in the Chinese population, IVS3-106A, IVS3-99A, exon3 130G, IVS4-299G, IVS4-293G, IVS4+211C, IVS4 +230C, exon6 499A, exon6 588A, IVS7-68T, IVS9+244G, and IVS10-153T. Our results also indicated that three novel SNPs produced Jk^a and Jk^b antigens in Chinese individuals.     

Association of interleukin-1B (IL-1B) gene polymorphisms with risk of gastric cancer in Chinese population

The incidence of gastric cancer (GC) in China is among the highest in the world. In present work, 154 patients with GC and 166 healthy controls in population of north-western China were investigated to evaluate the genetic associations of IL-1B gene single nucleotide polymorphisms (SNP) and variable number tandem repeat (VNTR) polymorphisms of IL-1RN gene with increased risk of GC. The frequency of IL-1B+3954C/T was significantly higher in GC cases group (25.97%) than that in controls (4.82%) with odds ratio (OR)=6.93 (95% confidence interval [CI] 3.13-15.36); the frequencies of IL-1B-31C/T, IL-1B-31C/C and IL-1B-511C/T genotypes were also higher in GC cases group (51.95%, 23.38% and 50.65%) than those in controls (46.99%, 19.88% and 42.77%) with OR=1.48 (95% CI 0.88-2.49), OR=1.58 (95% CI 0.84-2.95) and OR=1.39 (95% CI 0.80-2.41), respectively. The results show that these SNPs of IL-1B gene are associated with significantly increased risk of GC. This is the first report that IL-1B+3954C/T heterozygote is associated with greatly increased risk of GC. The results of this study did not support the report that IL-1RN*2+ genotypes were associated with increased risk of GC in Chinese population.     

Association of cytokines genes (ILL, IL1RN, TNF, LTA, IL6, IL8, IL0) polymorphic markers with chronic obstructive pulmonary disease

The purpose of this study was to investigate the possible roles of the cytokines genes in the development of chronic obstructive pulmonary disease (COPD). Polymorphisms in the genes encoding IL1B, IL1RN, TNFA, LTA, IL6, IL8 H IL10 were investigated in COPD patients (N = 319) and healthy individuals (N = 403) living in Ufa, the Republic of Bashkortostan. We observed that IL1RN*2/IL1RN*2 genotype of ILRN gene was associated with susceptibility for COPD (9.8% vs. 4.67%; chi(2)= 5.45, df= 1, P = 0.02; OR = 2.21). Analysis of the LTA gene polymorphic locus A252G showed that in patients with COPD, the frequency of the GG genotype was significantly higher than that in the control group (7.84% vs. 3.72%; chi(2) = 5.00, df= 1, P = 0.025). The increase of this genotype was significant in case of stage IV of COPD (11.18% vs. 4.79%; chi(2) = 3.075, df= 1, P = 0.07). Frequency of genotype combination TNFA-308 G/G and LTA252 A/A significantly decreased in COPD group (38.55% vs. 46.93% in control group; chi(2) = 8.82, df= 1, P = 0.0039). The frequency of GG genotype of the IL6 gene was higher in the patients with stage IV of COPD (43.75% vs. 31.54%, chi(2) = 4.14, P = 0.041). Our results indicate that the genotype frequency of the T(-511)C, T3953C of IL1B, G(-308)A of TNFA, G(-1 74)C of IL6, A(-251)C of IL8 and C(-627)A of ILl0 genes polymorphisms was similar in COPD and healthy control groups.     

The association between Japanese primary open-angle glaucoma and normal tension glaucoma patients and the optineurin gene

Glaucoma represents one of the most common eye diseases and is characterized by progressive loss of visual fields. In the more advanced stages bilateral blindness may result, due to optic nerve atrophy and an excavated optic nerve head. Open-angle glaucoma is one of the main disease subsets, which may be further divided into high tension primary open-angle glaucoma (POAG) and normal tension glaucoma (NTG). Recently, the optineurin (OPTN) gene was identified as a causative factor for NTG. Alterations in this gene were found in Caucasian families with NTG. In particular, c.458G>A, c.691-692insAG and c.1944G>A were shown to be risk factors. Since NTG is reported to be the most common form of glaucoma in Japan, and to identify if the OPTN gene plays a role in POAG, the DNAs from 148 unrelated Japanese patients with NTG, 165 patients with POAG and 196 unrelated controls who were not suffering glaucoma were investigated by appropriate genotyping techniques. No glaucoma-specific mutations were found in the OPTN gene in Japanese glaucoma patients. However, some novel single-nucleotide polymorphisms (SNPs) in the exons and introns are reported in this paper for the first time.S. Tang and Y. Toda contributed to the same degree for this study     

Population specificity of the DNAI1 gene mutation spectrum in primary ciliary dyskinesia (PCD)

Background

Mutations in the DNAI1 gene, encoding a component of outer dynein arms of the ciliary apparatus, are the second most important genetic cause of primary ciliary dyskinesia (PCD), the genetically heterogeneous recessive disorder with the prevalence of ~1/20,000. The estimates of the DNAI1 involvement in PCD pathogenesis differ among the reported studies, ranging from 4% to 10%.

Methods

The coding sequence of DNAI1 was screened (SSCP analysis and direct sequencing) in a group of PCD patients (157 families, 185 affected individuals), the first ever studied large cohort of PCD patients of Slavic origin (mostly Polish); multiplex ligation-dependent probe amplification (MLPA) analysis was performed in a subset of ~80 families.

Results

Three previously reported mutations (IVS1+2-3insT, L513P and A538T) and two novel missense substitutions (C388Y and G515S) were identified in 12 families (i.e. ~8% of non-related Polish PCD patients). The structure of background SNP haplotypes indicated common origin of each of the two most frequent mutations, IVS1+2-3insT and A538T. MLPA analysis did not reveal any significant differences between patients and control samples. The Polish cohort was compared with all the previously studied PCD groups (a total of 487 families): IVS1+2-3insT remained the most prevalent pathogenetic change in DNAI1 (54% of the mutations identified worldwide), and the increased global prevalence of A538T (14%) was due to the contribution of the Polish cohort.

Conclusions

The worldwide involvement of DNAI1 mutations in PCD pathogenesis in families not preselected for ODA defects ranges from 7 to 10%; this global estimate as well as the mutation profile differs in specific populations. Analysis of the background SNP haplotypes suggests that the increased frequency of chromosomes carrying A538T mutations in Polish patients may reflects local (Polish or Slavic) founder effect. Results of the MLPA analysis indicate that no large exonic deletions are involved in PCD pathogenesis.     

Cytokine gene polymorphisms and susceptibility to cutaneous leishmaniasis in Iranian patients

Cutaneous Leishmaniasis (CL) is one of the most prevalent clinical forms of leishmaniasis. Preliminary data suggest that cytokine gene polymorphisms can contribute to resistance or susceptibility to CL. Therefore, we investigated the association of functional polymorphisms in four cytokine genes with susceptibility to, and clinical outcome of CL. A total of 201 patients with self-healing cutaneous leishmaniasis (SCL) and 92 asymptomatic infected controls (AIC) from Fars province as well as 58 patients with chronic cutaneous leishmaniasis (CCL) and their 688 normal controls (normal Iranian population or NIP) who were collected from the different areas of Iran were included in the study. The allele-specific oligonucleotide polymerase chain reaction (ASO-PCR) or PCR-RFLP (restriction fragment length polymorphism) methods were used for genotyping. The frequency of TNF-alpha -308 G-->A and TNF-beta +252 G-->A gene polymorphisms were not different between studied groups. Distribution of IFN-gamma +874 A-->T and IL-4 -590 C-->T polymorphism were also compared between SCl or CCL patients and their controls. IFN-gamma +874 A-->T polymorphism was less common in CCL patients compared to the NIP (chi(2)=12.53, p=0.0019). Significant differences in frequency of IL-4 -590 C -->T polymorphism were also found between the SCL and AIC (chi(2)=8.64, p=0.003). In conclusion, our results suggest that functional genetic variants in the IL-4 promoter could influence the risk of developing CL while the polymorphism in the first intron of the IFN-gamma gene might influence the progression of disease towards CCL.     

Genetic variants at the resistin locus are associated with the plasma resistin concentration and cardiovascular risk factors

OBJECTIVE: To examine the relation of the single nucleotide polymorphisms (SNPs) of the resistin gene on the plasma resistin concentration and cardiovascular risk factors. METHODS AND RESULTS: Plasma resistin concentrations were measured and SNP -420C>G, +157C>T, and +299G>A genotyped in our Finnish population-based cohort. Association analyses were performed in the control group of the cohort (n=515). In addition, the hypertension group (n=505), representing a high-risk group, was analyzed for these SNP's and the frequencies were compared with the low-risk control group. Resistin concentration differed significantly between the SNP genotypes, the common homozygotes having the lowest concentration in every SNP (p<0.01). After adjustment for age, sex, and BMI SNP -420C-C homozygotes had the lowest IGFBP-1 (p=0.001), the highest GHbA(1c) (p=0.028) in all the subjects and the lowest quick index (p<0.001) and the highest insulin (p<0.001) among female subjects of the control cohort. Plasma triglycerides were the lowest among G-G homozygotes (p=0.006). In addition, the SNP -420C allele was more frequent among hypertensive than control cohort (p=0.018). CONCLUSIONS: The results imply that genetic variation seems to have a role in the determination of plasma resistin level. SNP -420C-C homozygozity status seems to be associated with more deleterious metabolic profile.     

A CHRNA5 allele related to nicotine addiction and schizophrenia

Schizophrenia and nicotine addiction are both highly heritable phenotypes. Because individuals with schizophrenia have a higher rate of smoking than those in the general population, one could hypothesize that genes associated with smoking might be overrepresented in schizophrenia and thus help explain their increased smoking incidence. Although a number of genes have been proposed to explain the increased smoking risk in schizophrenia, none of them have been consistently linked to smoking and schizophrenia, and thus difficult to explain the increased smoking in schizophrenia. A functional smoking-related nicotinic acetylcholine receptor α5 subunit gene (CHRNA5) nonsynonymous single nucleotide polymorphism (SNP) rs16969968 (Asp398Asn) has recently been discovered and replicated. As such, we tested whether this variant contributes to smoking in schizophrenia in a sample of 313 schizophrenia patients and 525 controls. The Asp398Asn risk allele is significantly associated with smoking severity independently in schizophrenia patient smokers (P = 0.001) and control smokers (P = 0.029). Furthermore, the same risk allele is significantly associated with schizophrenia in both Caucasian (P = 0.022) and African-American (P = 0.006) nonsmoker schizophrenia patients compared with control nonsmokers. Intriguingly, this SNP was not significantly associated with smoking status (smokers vs. nonsmokers) in either schizophrenia patients or controls. Therefore, our study identifies a genetic variant that is simultaneously linked to smoking and schizophrenia in the same cohort, but whether this SNP contributes to the increased smoking prevalence in schizophrenia patients requires additional studies.     

Acquired pits of the optic nerve in glaucoma

An acquired pit of the optic nerve (APON) is a discrete, focal area of depression within the optic cup at the level of the lamina cribrosa. It is an under-diagnosed sign of glaucoma damage due to its subtle appearance. APONs occur more frequently unilaterally and in patients with normal-tension glaucoma (NTG). They often correspond to a deep, sharp-margined scotoma approaching or involving fixation. Given the location and progressive nature of the associated visual field defects, glaucoma patients and glaucoma suspects should be evaluated for this sign of localized optic nerve damage.     

Variants at the endocannabinoid receptor CB1 gene (CNR1) and insulin sensitivity, type 2 diabetes, and coronary heart disease

Inhibition of the endocannabinoid receptor CB1 improves insulin sensitivity, lowers glycemia, and slows atherosclerosis. We analyzed whether common variants in the gene encoding CB1, CNR1, are associated with insulin resistance, risk of type 2 diabetes (T2D) or coronary heart disease (CHD). We studied 2,411 participants of the Framingham Offspring Study (mean age 60 years, 52% women) for quantitative traits and CHD, and the Framingham SHARe database for T2D risk. We genotyped 19 single-nucleotide polymorphisms (SNPs) that tagged 85% (at r(2) = 0.8) of common (>5%) CNR1 SNPs. Fasting blood glucose and insulin at the 7th (1999-2001) exam were collected. We used age-, sex-, BMI-adjusted models to test additive associations of genotype with homeostasis model assessment of insulin resistance (HOMA(IR)) (linear mixed-effect models), T2D, or CHD. To account for multiple tests of SNPs, we generated empirical P values. The C allele at SNP rs806365 (frequency, 57.4%), ~4.1 kb 3' from CNR1, was associated with increased HOMA(IR) (n = 2,261, β = 0.05 per C, empirical P = 0.01), risk of T2D (674 cases, odds ratio = 1.19 per C, nominal P = 0.01) and CHD (237 cases, hazard ratio = 1.23 per C, nominal P = 0.04). The association of rs806365 with HOMA(IR) was replicated in a meta-analysis of two independent cohorts (National Health and Nutrition Examination Survey III genetic cohort (NHANES-III) plus Partners Case-Control Diabetes Study; 2,540 white individuals, β = 0.037, nominal P = 0.007), but not in the large Meta-Analyses of Glucose and Insulin-related traits Consortium (MAGIC) Consortium (n = 29,248, nominal P = 0.74). The association of rs806365 was not replicated either with T2D in Diabetes Genetics Replication and Meta-analysis (DIAGRAM) (n = 10,128, nominal P = 0.31), or with CHD in PROCARDIS (n = 13,614, nominal P = 0.37). Although supported by initial results, we found no reproducible statistical association of common variation at CNR1 with insulin resistance, T2D, or CHD.     

五种苏铁属植物的核形态

报道了苏铁属（Cycas L.)5种植物的染色体数目和核型,除多歧苏铁外,其他种均为首次报道。5个种的体细胞中期染色体核型公式分别为：滇南苏铁C.diannanensis K(2n)=2x=22=2m 4sm 4st 12T;潭清苏铁C.tanqingii K(2n)=2x=22=2m 8sm 2st 10T;多歧苏的Cmultipinnata K(2n)=2x=22=4m 8st 2st 8T;巴兰萨苏铁C.balansae K(2n)=2x=xx=2m 4sm 6st 10T。石山苏铁C.miquelii K(2n)=22=2m 6sm(1SAT) 4st 10T;核型均属于3B型。本研究结果支持苏铁属植物的核型从不对称进化的观点;同时,支持将巴兰萨苏铁和石山苏铁归入攀枝花苏铁组的台湾苏铁亚组的观点。