Genetic association and differential expression of PITX2 with acute appendicitis.

Appendicitis affects 9% of Americans and is the most common diagnosis requiring hospitalization of both children and adults. We performed a genome-wide association study of self-reported appendectomy with 18,773 affected adults and 114,907 unaffected adults of European American ancestry. A significant association with appendectomy was observed at 4q25 near the gene PITX2 (rs2129979, p value = 8.82 × 10-14) and was replicated in an independent sample of Caucasians (59 affected, 607 unaffected; p value = 0.005). Meta-analysis of the associated variant across our two cohorts and cohorts from Iceland and the Netherlands (in which this association had previously been reported) showed strong cumulative evidence of association (OR = 1.12; 95% CI 1.09-1.14; p value = 1.81 × 10-23) and some evidence for effect heterogeneity (p value = 0.03). Eight other loci were identified at suggestive significance in the discovery GWAS. Associations were followed up by measuring gene expression across resected appendices with varying levels of inflammation (N = 75). We measured expression of 27 genes based on physical proximity to the GWAS signals, evidence of being targeted by eQTLs near the signals according to RegulomeDB (score = 1), or both. Four of the 27 genes (including PITX2) showed significant evidence (p values < 0.0033) of differential expression across categories of appendix inflammation. An additional ten genes showed nominal evidence (p value < 0.05) of differential expression, which, together with the significant genes, is more than expected by chance (p value = 6.6 × 10-12). PITX2 impacts morphological development of intestinal tissue, promotes an anti-oxidant response, and its expression correlates with levels of intestinal bacteria and colonic inflammation. Further studies of the role of PITX2 in appendicitis are warranted.

Circulating Interleukin-6 concentration covaries inversely with self-reported sleep duration as a function of polymorphic variation in the glucocorticoid receptor.

Growing evidence links extremes of self-reported sleep duration with higher circulating markers of inflammatory disease risk, although not all findings are consistent. Extremes of sleep duration also associate with activation of the hypothalamic-pituitary-adrenocortical (HPA) system and the peripheral release of cortisol, a glucocorticoid (GC) important in downregulating transcription of pro-inflammatory molecules. Polymorphic variation in the gene encoding the GC receptor (GR; NR3C1) modulates cellular sensitivity to GC-mediated anti-inflammatory signaling, thereby affecting levels of pro-inflammatory molecules. Thus, we hypothesized that extremes of self-reported sleep duration may covary with circulating levels of inflammatory markers as a function of allelic variation in NR3C1. Specifically, we examine the possibility that a single nucleotide polymorphism of the GR gene-(rs6198), the minor (G) allele of which confers reduced GR sensitivity-moderates an association of sleep duration with interleukin (IL)-6 and C-reactive protein (CRP) among a large sample (IL-6: N = 857; CRP: N = 929) of midlife community volunteers of European ancestry. Findings showed that sleep duration varied inversely with IL-6 (ß = -0.087, p = .012), and this association was stronger among individuals homozygous for the rs6198 G-allele compared to alternate genotypes (ß = -0.071, p = .039). We also found that sleep duration showed a U-shaped association with CRP (polynomial term: ß = 0.093, p = .006), which was not moderated by rs6198 genotype. In conclusion, we show that a common genetic variant in the GR moderates an inverse association of self-reported sleep duration with circulating IL-6, possibly contributing to the increased disease risk observed among some short sleepers.

Liver-specific deletion of augmenter of liver regeneration accelerates development of steatohepatitis and hepatocellular carcinoma in mice.

BACKGROUND & AIMS: Augmenter of liver regeneration (ALR, encoded by GFER) is a widely distributed pleiotropic protein originally identified as a hepatic growth factor. However, little is known about its roles in hepatic physiology and pathology. We created mice with liver-specific deletion of ALR to study its function. METHODS: We developed mice with liver-specific deletion of ALR (ALR-L-KO) using the albumin-Cre/LoxP system. Liver tissues were collected from ALR-L-KO mice and ALR(floxed/floxed) mice (controls) and analyzed by histology, reverse-transcription polymerase chain reaction, immunohistochemistry, electron microscopy, and techniques to measure fibrosis and lipids. Liver tissues from patients with and without advanced liver disease were determined by immunoblot analysis. RESULTS: Two weeks after birth, livers of ALR-L-KO mice contained low levels of ALR and adenosine triphosphate (ATP); they had reduced mitochondrial respiratory function and increased oxidative stress, compared with livers from control mice, and had excessive steatosis, and hepatocyte apoptosis. Levels of carbamyl-palmitoyl transferase 1a and ATP synthase subunit ATP5G1 were reduced in livers of ALR-L-KO mice, indicating defects in mitochondrial fatty acid transport and ATP synthesis. Electron microscopy showed mitochondrial swelling with abnormalities in shapes and numbers of cristae. From weeks 2-4 after birth, levels of steatosis and apoptosis decreased in ALR-L-KO mice, and numbers of ALR-expressing cells increased, along with ATP levels. However, at weeks 4-8 after birth, livers became inflamed, with hepatocellular necrosis, ductular proliferation, and fibrosis; hepatocellular carcinoma developed by 1 year after birth in nearly 60% of the mice. Hepatic levels of ALR were also low in ob/ob mice and alcohol-fed mice with liver steatosis, compared with controls. Levels of ALR were lower in liver tissues from patients with advanced alcoholic liver disease and nonalcoholic steatohepatitis than in control liver tissues. CONCLUSIONS: We developed mice with liver-specific deletion of ALR, and showed that it is required for mitochondrial function and lipid homeostasis in the liver. ALR-L-KO mice provide a useful model for investigating the pathogenesis of steatohepatitis and its complications.

A Hierarchical Factor Model of Executive Functions in Adolescents: Evidence of Gene-Environment Interplay.

Executive functions (EF) are a complex set of neurodevelopmental, higher-ordered processes that are especially salient during adolescence. Disruptions to these processes are predictive of psychiatric problems in later adolescence and adulthood. The objectives of the current study were to characterize the latent structure of EF using bifactor analysis and to investigate the independent and interactive effects of genes and environments on EF during adolescence. Using a representative young adolescent sample, we tested the interaction of a polymorphism in the serotonin transporter gene (5-HTTLPR) and parental supervision for EF through hierarchical linear regression. To account for the possibility of a hierarchical factor structure for EF, a bifactor analysis was conducted on the eight subtests of the Delis-Kaplan Executive Functions System (D-KEFS). The bifactor analysis revealed the presence of a general EF construct and three EF subdomains (i.e., conceptual flexibility, inhibition, and fluency). A significant 5-HTTLPR by parental supervision interaction was found for conceptual flexibility, but not for general EF, fluency or inhibition. Specifically, youth with the L/L genotype had significantly lower conceptual flexibility scores compared to youth with S/S or S/L genotypes given low levels of parental supervision. Our findings indicate that adolescents with the L/L genotype were especially vulnerable to poor parental supervision on EF. This vulnerability may be amenable to preventive interventions.

X chromosome-linked IRAK-1 polymorphism is a strong predictor of multiple organ failure and mortality postinjury.

OBJECTIVE(S): Clinical research characterizing the mechanisms responsible for sex-based outcome differences postinjury remain conflicting. We sought to characterize an X chromosome-linked IRAK-1 (IL-1 receptor-associated kinase) polymorphism as an alternative mechanism responsible for sex differences postinjury. IRAK-1 is key intermediate in the toll-like receptor (TLR) pathway thought to drive inflammation postinjury. METHODS: A prospective cohort study was performed over a 24-month period. Bluntly injured patients requiring intensive care unit admission were enrolled, whereas patients with isolated brain and spinal cord injuries were excluded. Outcomes of interest included multiple organ failure (MOF, Marshall MOD score > 5) and mortality. Logistic regression was utilized to determine the independent risk of poor outcome associated with the IRAK-1 variant after controlling for important differences. RESULTS: In an enrolled cohort of 321 patients, the IRAK-1 variant was common (12.5%). Patients with and without the variant were similar in age, injury severity, and 24hr blood transfusion. After controlling for important confounders, the IRAK1 variant was independently associated with more than eightfold (OR = 8.4, P = 0.005, 95% CI: 1.9-37.1) and 11-fold (OR = 11.8, P = 0.037, 95% CI: 1.1-121) greater risk of MOF and mortality, respectively. These differences were most prominent in men, whereas women heterozygous for the variant demonstrated worse outcome in a dose-dependent fashion. CONCLUSIONS: The IRAK1 polymorphism is a strong independent predictor of MOF and mortality postinjury and represents a common variant with prognostic potential. These data demonstrate the importance of TLR signaling postinjury and supports that a genetic mechanism may drive sex outcome differences postinjury.

Cross-sectional analysis of Toll-like receptor variants and bacterial vaginosis in African-American women with pelvic inflammatory disease.

OBJECTIVE: Bacterial vaginosis (BV) is a common condition associated with serious complications including pelvic inflammatory disease (PID). However, the pathogenesis of BV is poorly understood. Toll-like receptors (TLR) are responsible for microbial recognition and elimination through inflammatory responses. TLR variants have been implicated in infectious and inflammatory diseases and may be involved in BV pathogenesis. We conducted a cross-sectional study to determine if TLR variants are associated with BV. METHODS: Logistic regression was used to test associations between 14 variants assayed in 6 genes (TLR1, TLR2, TLR4, TLR6, TIRAP and MyD88) and BV/intermediate flora among 192 African-American women with clinical PID from the PID Evaluation and Clinical Health (PEACH) Study. Additionally, we examined associations between variants and endometrial BV-associated anaerobes. To account for multiple comparisons a permutated p<0.003 was used to determine statistical significance. RESULTS: African-American women with PID carrying the AA genotype for TLR2 SNP rs1898830 had a threefold increased rate of BV/intermediate flora (OR 2.9, 95% CI 1.2 to 7.3). This was not significant after accounting for multiple comparisons (p=0.0201). TLR2 variants rs1898830, rs11938228 and rs3804099 were associated with increased endometrial anaerobic gram-negative rods (p=0.0107, p=0.0076 p=0.0121), anaerobic non-pigmented Gram-negative rods (p=0.0231, p=0.0083, p=0.0044), and anaerobic Gram-positive cocci (p=0.0596, p=0.0640, p=0.1459). CONCLUSIONS: Among African-American women with PID, we observed trends between TLR2 variants, BV/intermediate flora, and BV-associated microbes. This provides some insight into BV pathogenesis. As not all BV-associated microbes may lead to pathology, future studies should focus on associations between TLR variants and individual BV-associated microbes.

Genetic variation in human NPY expression affects stress response and emotion.

Understanding inter-individual differences in stress response requires the explanation of genetic influences at multiple phenotypic levels, including complex behaviours and the metabolic responses of brain regions to emotional stimuli. Neuropeptide Y (NPY) is anxiolytic and its release is induced by stress. NPY is abundantly expressed in regions of the limbic system that are implicated in arousal and in the assignment of emotional valences to stimuli and memories. Here we show that haplotype-driven NPY expression predicts brain responses to emotional and stress challenges and also inversely correlates with trait anxiety. NPY haplotypes predicted levels of NPY messenger RNA in post-mortem brain and lymphoblasts, and levels of plasma NPY. Lower haplotype-driven NPY expression predicted higher emotion-induced activation of the amygdala, as well as diminished resiliency as assessed by pain/stress-induced activations of endogenous opioid neurotransmission in various brain regions. A single nucleotide polymorphism (SNP rs16147) located in the promoter region alters NPY expression in vitro and seems to account for more than half of the variation in expression in vivo. These convergent findings are consistent with the function of NPY as an anxiolytic peptide and help to explain inter-individual variation in resiliency to stress, a risk factor for many diseases.

Racial variation in toll-like receptor variants among women with pelvic inflammatory disease.

BACKGROUND: Racial disparities exist in gynecological diseases. Variations in Toll-like receptor (TLR) genes may alter signaling following microbial recognition. METHODS: We explored genotypic differences in 6 functional variants in 4 TLR genes (TLR1, TLR2, TLR4, TLR6) and the adaptor molecule TIRAP between 205 African American women and 51 white women with clinically suspected pelvic inflammatory disease (PID). A permutated P < .007 was used to assess significance. Associations between race and endometritis and/or upper genital tract infection (UGTI) were explored. Logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: The TT genotype for TLR1 rs5743618, the GG genotype for TLR1 rs4833095, the CC genotype for TLR2 rs3804099, the TLR6 rs5743810 T allele, and the CC genotype for TIRAP rs8177374 significantly differed between races (P < .007). African American race was associated with endometritis and/or UGTI (OR, 4.2 [95% CI, 2.0-8.7]; P = .01). Among African Americans, the TLR6 rs5743810 T allele significantly decreased endometritis and/or UGTI (OR, 0.4 [95% CI, .2-.9]; P = .04). Additionally, rs5743618, rs4833095, and rs8177374 increased endometritis and/or UGTI, albeit not significantly. CONCLUSIONS: Among women with PID, TLR variants that increase inflammation are associated with African American race and may mediate the relationship between race and endometritis and/or UGTI.

GJC2 missense mutations cause human lymphedema.

Lymphedema is the clinical manifestation of defects in lymphatic structure or function. Mutations identified in genes regulating lymphatic development result in inherited lymphedema. No mutations have yet been identified in genes mediating lymphatic function that result in inherited lymphedema. Survey microarray studies comparing lymphatic and blood endothelial cells identified expression of several connexins in lymphatic endothelial cells. Additionally, gap junctions are implicated in maintaining lymphatic flow. By sequencing GJA1, GJA4, and GJC2 in a group of families with dominantly inherited lymphedema, we identified six probands with unique missense mutations in GJC2 (encoding connexin [Cx] 47). Two larger families cosegregate lymphedema and GJC2 mutation (LOD score = 6.5). We hypothesize that missense mutations in GJC2 alter gap junction function and disrupt lymphatic flow. Until now, GJC2 mutations were only thought to cause dysmyelination, with primary expression of Cx47 limited to the central nervous system. The identification of GJC2 mutations as a cause of primary lymphedema raises the possibility of novel gap-junction-modifying agents as potential therapy for some forms of lymphedema.

The brain-derived neurotrophic factor Val66Met polymorphism moderates an effect of physical activity on working memory performance.

Physical activity enhances cognitive performance, yet individual variability in its effectiveness limits its widespread therapeutic application. Genetic differences might be one source of this variation. For example, carriers of the methionine-specifying (Met) allele of the brain-derived neurotrophic factor (BDNF) Val66Met polymorphism have reduced secretion of BDNF and poorer memory, yet physical activity increases BDNF levels. To determine whether the BDNF polymorphism moderated an association of physical activity with cognitive functioning among 1,032 midlife volunteers (mean age = 44.59 years), we evaluated participants' performance on a battery of tests assessing memory, learning, and executive processes, and evaluated their physical activity with the Paffenbarger Physical Activity Questionnaire. BDNF genotype interacted robustly with physical activity to affect working memory, but not other areas of cognitive functioning. In particular, greater levels of physical activity offset a deleterious effect of the Met allele on working memory performance. These findings suggest that physical activity can modulate domain-specific genetic (BDNF) effects on cognition.

Variants of SLC6A4 in depression risk following severe TBI.

BACKGROUND: Post-traumatic depression (PTD) may be a result of several factors like secondary injury chemical cascades as well as psycho-social factors following traumatic brain injury (TBI). While the role of serotonin in the pathology and treatment of idiopathic major depression may be somewhat controversial, it is unclear what role serotonin may play in PTD following a TBI. OBJECTIVE: To assess serotonergic function and genetic risk for PTD development over 1 year following TBI. RESEARCH DESIGN: Examination of variation in the serotonin transporter gene [SLC6A4 (5-HTTLPR, rs25331, and a variable number of tandem repeats variant in Intron 2)] in 109 subjects with moderate-severe injury. Depression was assessed using the Patient Health Questionnaire (PHQ-9) at 6 and/or 12 months post-injury. MAIN OUTCOMES AND RESULTS: At 6 months post-injury, subjects with a history of pre-morbid mood disorders and 5-HTTLPR L-homozygotes were at greater risk for PTD. Contrary to major depression, subjects without pre-morbid mood disorders (n = 80) and S-carriers were 2.803-times less likely to be depressed compared to L-homozygotes. At 12 months post-injury, LG-carriers were also less likely to experience PTD. Temporal analysis also showed 5-HTTLPR associations in PTD development across recovery. CONCLUSIONS: This study suggests a unique injury- and temporally-specific interaction between TBI and genetic risk for depression.

Mannose binding lectin genotypes are not associated with increased risk of unexplained recurrent pregnancy loss.

PURPOSE: Immune response to infections has been associated with recurrent pregnancy loss (RPL). Low plasma mannose binding lectin (MBL) levels, an innate immunity factor in infections, has been related to RPL. In this study, we tested the hypothesis that MBL genotypes that are known to cause reduced plasma MBL levels are significantly more frequent among women experiencing unexplained RPL. METHODS: This study included 219 Caucasian women diagnosed with unexplained RPL and 236 control women. All participants were genotyped for two promoter (-550 C > G and -221 G > C) and three missense (R52C, G54D and G57E) mutations in exon 1. These mutations are known to be associated with variations in plasma MBL levels. Genotype frequencies were estimated by gene counting and were compared to the expectation of Hardy-Weinberg equilibrium by chi-squared (X(2)) analysis and Fisher's exact test. Allele and genotype frequencies were compared in cases and controls using X(2) contingency table analysis. RESULTS: There was no difference in demographics between cases and controls. The number of miscarriages in the participants with RPL ranged from 2 to 10 spontaneous abortions (SAB's) per participant. Populations genotyped were in Hardy-Weinberg equilibrium. There was no association between a history of RPL and multi-SNP genotypes at the MBL locus. In unexplained RPL, the number of SAB's and live birth rates were unaffected by MBL genotype. There was no association between MBL genotype and the risk of unexplained RPL. The occurrence of live birth was not associated with MBL genotype. CONCLUSION: Genotypes known to cause low MBL plasma levels are not associated with an increased risk of unexplained RPL.

Variants in toll-like receptor 1 and 4 genes are associated with Chlamydia trachomatis among women with pelvic inflammatory disease.

BACKGROUND: Toll-like receptors (TLRs) are involved in the innate immune response. We examined whether TLR variants are associated with Chlamydia trachomatis infection among women with pelvic inflammatory disease (PID). METHODS: We tested whether 18 tagging single nucleotide polymorphisms (tagSNPs) assayed in 4 TLR genes (TLR1, TLR2, TLR4, TLR6) and 2 adaptor molecules (TIRAP, MyD88) were associated with C. trachomatis among 205 African American women with clinically suspected PID from the PID Evaluation and Clinical Health Study. Logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). An empirical P value of <.004 was considered significant. RESULTS: Women with PID who carried the TLR4 rs1927911 CC genotype had significantly increased odds of C. trachomatis (OR, 3.7; 95% CI, 1.6-8.8; P = .002). The TLR1 rs5743618TT genotype was also associated with C. trachomatis (OR, 2.8; 95% CI, 1.3-6.2; P = .008). CONCLUSIONS: Among African American women with PID, variants in the TLR1 and TLR4 genes, which may increase signaling, were associated with increased C. trachomatis infection.

Melville's "Bartleby, the Scrivener: A Story of Wall-Street": The Vicissitudes of Treating a Difficult Patient.

Taking the liberty of imagining the lawyer in Melville's "Bartleby, the Scrivener" as narrator/therapist and Bartleby as patient, this article, written with the therapist/reader in mind, traces the vicissitudes of countertransference and speculates on what constitutes a "good enough" therapeutic effort.

Interpretation of genetic association studies: markers with replicated highly significant odds ratios may be poor classifiers.

Recent successful discoveries of potentially causal single nucleotide polymorphisms (SNPs) for complex diseases hold great promise, and commercialization of genomics in personalized medicine has already begun. The hope is that genetic testing will benefit patients and their families, and encourage positive lifestyle changes and guide clinical decisions. However, for many complex diseases, it is arguable whether the era of genomics in personalized medicine is here yet. We focus on the clinical validity of genetic testing with an emphasis on two popular statistical methods for evaluating markers. The two methods, logistic regression and receiver operating characteristic (ROC) curve analysis, are applied to our age-related macular degeneration dataset. By using an additive model of the CFH, LOC387715, and C2 variants, the odds ratios are 2.9, 3.4, and 0.4, with p-values of 10(-13), 10(-13), and 10(-3), respectively. The area under the ROC curve (AUC) is 0.79, but assuming prevalences of 15%, 5.5%, and 1.5% (which are realistic for age groups 80 y, 65 y, and 40 y and older, respectively), only 30%, 12%, and 3% of the group classified as high risk are cases. Additionally, we present examples for four other diseases for which strongly associated variants have been discovered. In type 2 diabetes, our classification model of 12 SNPs has an AUC of only 0.64, and two SNPs achieve an AUC of only 0.56 for prostate cancer. Nine SNPs were not sufficient to improve the discrimination power over that of nongenetic predictors for risk of cardiovascular events. Finally, in Crohn's disease, a model of five SNPs, one with a quite low odds ratio of 0.26, has an AUC of only 0.66. Our analyses and examples show that strong association, although very valuable for establishing etiological hypotheses, does not guarantee effective discrimination between cases and controls. The scientific community should be cautious to avoid overstating the value of association findings in terms of personalized medicine before their time.

Association of KIBRA rs17070145 polymorphism and episodic memory in individuals with severe TBI.

BACKGROUND: Studies implicate single nucleotide polymorphism (SNP) rs17070145, a common T → C polymorphism on the KIBRA gene, in mediating differences in episodic memory. In healthy adults, T-allele carriers perform better than non-carriers on episodic memory measures. However, this association is reversed in adults with subjective memory complaints and populations vulnerable to memory deficits, a problem common in traumatic brain injury (TBI). METHODS: This study assessed associations between variation in the KIBRA gene and cognitive function in 129 adults with severe TBI. In addition to other executive functioning and functional/global outcomes, the Buschke Selective Reminding Test (SRT), Rey-Osterrieth Complex Figure Test and California Verbal Learning Test-II (CVLT-II) were administered 6 and 12 months post-injury. RESULTS: T-allele non-carriers performed better than carriers on multiple episodic memory measures. At 6 months, T-allele non-carriers performed better for delayed recall measures on the SRT. At 12 months, T-allele non-carriers performed better on multiple SRT measures and on List-B learning with CVLT-II. No associations occurred with executive function or global outcome measures. CONCLUSION: These results suggest that rs17070145 T-allele effects are specific to episodic memory and support the hypothesis that associations between rs17070145 variation and memory are disparate between healthy and impaired populations.

Multi-institutional prostate cancer study of genetic susceptibility in populations of African descent.

Prostate cancer disparities have been reported in men of African descent who show the highest incidence, mortality, compared with other ethnic groups. Few studies have explored the genetic and environmental factors for prostate cancer in men of African ancestry. The glutathione-S-transferases family conjugates carcinogens before their excretion and is expressed in prostate tissue. This study addressed the role of GSTM1 and GSTT1 deletions on prostate cancer risk in populations of African descent. This multi-institutional case-control study gathered data from the Genetic Susceptibility to Environmental Carcinogens (GSEC) database, the African-Caribbean Cancer Consortium (AC3) and Men of African Descent and Carcinoma of the Prostate Consortium (MADCaP). The analysis included 10 studies (1715 cases and 2363 controls), five in African-Americans, three in African-Caribbean and two in African men. Both the GSTM1 and the GSTT1 deletions showed significant inverse associations with prostate cancer [odds ratio (OR): 0.90, 95% confidence interval (CI) 0.83-0.97 and OR 0.88, 95% CI: 0.82-0.96, respectively]. The association was restricted to Caribbean and African populations. A significant positive association was observed between GSTM1 deletion and prostate cancer in smokers in African-American studies (OR: 1.28, 95% CI: 1.01-1.56), whereas a reduced risk was observed in never-smokers (OR: 0.66, 95% CI: 0.46-0.95). The risk of prostate cancer increased across quartiles of pack-years among subjects carrying the deletion of GSTM1 but not among subjects carrying a functional GSTM1. Gene-environment interaction between smoking and GSTM1 may be involved in the etiology of prostate cancer in populations of African descent.

Chromosome 8q24 variants are associated with prostate cancer risk in a high risk population of African ancestry.

BACKGROUND: Earlier studies on the role of germline variations in the disproportionate higher burden of prostate cancer in men of African ancestry have been largely unrewarding. However, the successful replication of recent genome-wide association findings implicating some regions of chromosome 8q24 in the disparate prostate cancer susceptibility in men of European and African ancestry have been encouraging. This case-control study was designed to evaluate the association between germline variations in chromosome 8q24 and prostate cancer risk in Afro-Caribbean Tobago men, a population of predominantly West African ancestry. METHODS: High molecular weight genomic DNA was isolated from blood clots using Qiagen kits. Genotyping was performed on genomic DNA using a pre-designed TaqMan SNP assay according to the manufacture's protocol on a 7900HT Fast Real-Time PCR system (Applied Biosystems, Foster City, CA). RESULTS: SNP rs16901979 in region 2 was associated with significantly increased risk of prostate cancer (OR = 1.41, 95% confidence interval [CI] 1.02-1.95, P = 0.04) with the risk stronger in men with early-onset prostate cancer (OR = 2.37, 95% CI 1.40-3.99, P = 0.001). There was a tendency towards significantly increased risk for SNPs rs1447295 and rs6983267 in men with early-onset prostate cancer. CONCLUSIONS: The replication of the association of chromosome 8q24 variants with increased prostate cancer risk in Tobago men and the higher frequency of the risk alleles in controls in populations of African ancestry further strengthens the possible role of this genomic region in the disproportionate higher burden of prostate cancer in men of African ancestry.

Analysis of positional candidate genes in the AAA1 susceptibility locus for abdominal aortic aneurysms on chromosome 19.

BACKGROUND: Abdominal aortic aneurysm (AAA) is a complex disorder with multiple genetic risk factors. Using affected relative pair linkage analysis, we previously identified an AAA susceptibility locus on chromosome 19q13. This locus has been designated as the AAA1 susceptibility locus in the Online Mendelian Inheritance in Man (OMIM) database. METHODS: Nine candidate genes were selected from the AAA1 locus based on their function, as well as mRNA expression levels in the aorta. A sample of 394 cases and 419 controls was genotyped for 41 SNPs located in or around the selected nine candidate genes using the Illumina GoldenGate platform. Single marker and haplotype analyses were performed. Three genes (CEBPG, PEPD and CD22) were selected for DNA sequencing based on the association study results, and exonic regions were analyzed. Immunohistochemical staining of aortic tissue sections from AAA and control individuals was carried out for the CD22 and PEPD proteins with specific antibodies. RESULTS: Several SNPs were nominally associated with AAA (p < 0.05). The SNPs with most significant p-values were located near the CCAAT enhancer binding protein (CEBPG), peptidase D (PEPD), and CD22. Haplotype analysis found a nominally associated 5-SNP haplotype in the CEBPG/PEPD locus, as well as a nominally associated 2-SNP haplotype in the CD22 locus. DNA sequencing of the coding regions revealed no variation in CEBPG. Seven sequence variants were identified in PEPD, including three not present in the NCBI SNP (dbSNP) database. Sequencing of all 14 exons of CD22 identified 20 sequence variants, five of which were in the coding region and six were in the 3'-untranslated region. Five variants were not present in dbSNP. Immunohistochemical staining for CD22 revealed protein expression in lymphocytes present in the aneurysmal aortic wall only and no detectable expression in control aorta. PEPD protein was expressed in fibroblasts and myofibroblasts in the media-adventitia border in both aneurysmal and non-aneurysmal tissue samples. CONCLUSIONS: Association testing of the functional positional candidate genes on the AAA1 locus on chromosome 19q13 demonstrated nominal association in three genes. PEPD and CD22 were considered the most promising candidate genes for altering AAA risk, based on gene function, association evidence, gene expression, and protein expression.

Defective valves and abnormal mural cell recruitment underlie lymphatic vascular failure in lymphedema distichiasis.

Lymphatic vessels are essential for the removal of interstitial fluid and prevention of tissue edema. Lymphatic capillaries lack associated mural cells, and collecting lymphatic vessels have valves, which prevent lymph backflow. In lymphedema-distichiasis (LD), lymphatic vessel function fails because of mutations affecting the forkhead transcription factor FOXC2. We report that Foxc2(-/-) mice show abnormal lymphatic vascular patterning, increased pericyte investment of lymphatic vessels, agenesis of valves and lymphatic dysfunction. In addition, an abnormally large proportion of skin lymphatic vessels was covered with smooth muscle cells in individuals with LD and in mice heterozygous for Foxc2 and for the gene encoding lymphatic endothelial receptor, Vegfr3 (also known as Flt4). Our data show that Foxc2 is essential for the morphogenesis of lymphatic valves and the establishment of a pericyte-free lymphatic capillary network and that it cooperates with Vegfr3 in the latter process. Our results indicate that an abnormal interaction between the lymphatic endothelial cells and pericytes, as well as valve defects, underlie the pathogenesis of LD.