To determine CYP2C19 and CYP2C8 allele frequencies, 28 coding and/or functional variants were genotyped in 1250 African-American, Asian, Caucasian, Hispanic and Ashkenazi Jewish (AJ) individuals. The combined CYP2C19 variant allele frequencies ranged from ~0.30–0.41; however, the CYP2C8 frequencies were much lower (~0.04–0.13). After incorporating previously reported CYP2C9 genotyping results from these populations (36 total CYP2C variants), 16 multi-ethnic CYP2C haplotypes were inferred with frequencies >0.5%. Notably, the 2C19*17-2C9*1-2C8*2 haplotype was identified among African-Americans (8%) and Hispanics (2%), indicating that CYP2C19*17 does not always tag a CYP2C haplotype that encodes efficient CYP2C-substrate metabolism. The 2C19*1-2C9*2-2C8*3 haplotype was identified in all populations except African-Americans and additional novel haplotypes were identified in selected populations (e.g., 2C19*2-2C9*1-2C8*4, 2C19*4B-2C9*1-2C8*1), together indicating that both CYP2C19*17 and *2 can be linked with other CYP2C loss-of-function alleles. These results have important implications for pharmacogenomic association studies involving the CYP2C locus and are clinically relevant when administering CYP2C-substrate medications.
CYP2C19; CYP2C8; CYP2C9; clinical pharmacogenetics; linkage disequilibrium; haplotype
The Ashkenazi Jewish population has a several-fold higher prevalence of Crohn’s disease compared to non-Jewish European ancestry populations and has a unique genetic history. Haplotype association is critical to Crohn’s disease etiology in this population, most notably at NOD2, in which three causal, uncommon, and conditionally independent NOD2 variants reside on a shared background haplotype. We present an analysis of extended haplotypes which showed significantly greater association to Crohn’s disease in the Ashkenazi Jewish population compared to a non-Jewish population (145 haplotypes and no haplotypes with P-value < 10−3, respectively). Two haplotype regions, one each on chromosomes 16 and 21, conferred increased disease risk within established Crohn’s disease loci. We performed exome sequencing of 55 Ashkenazi Jewish individuals and follow-up genotyping focused on variants in these two regions. We observed Ashkenazi Jewish-specific nominal association at R755C in TRPM2 on chromosome 21. Within the chromosome 16 region, R642S of HEATR3 and rs9922362 of BRD7 showed genome-wide significance. Expression studies of HEATR3 demonstrated a positive role in NOD2-mediated NF-κB signaling. The BRD7 signal showed conditional dependence with only the downstream rare Crohn’s disease-causal variants in NOD2, but not with the background haplotype; this elaborates NOD2 as a key illustration of synthetic association.
haplotype association; Ashkenazi Jewish; Crohn’s disease; NF-κB signaling; synthetic association
This study was aimed to assess the diversity of the meconium microbiome and determine if the bacterial community is affected by maternal diabetes status.
The first intestinal discharge (meconium) was collected from 23 newborns stratified by maternal diabetes status: 4 mothers had pre-gestational type 2 diabetes mellitus (DM) including one mother with dizygotic twins, 5 developed gestational diabetes mellitus (GDM) and 13 had no diabetes. The meconium microbiome was profiled using multi-barcode 16S rRNA sequencing followed by taxonomic assignment and diversity analysis.
All meconium samples were not sterile and contained diversified microbiota. Compared with adult feces, the meconium showed a lower species diversity, higher sample-to-sample variation, and enrichment of Proteobacteria and reduction of Bacteroidetes. Among the meconium samples, the taxonomy analyses suggested that the overall bacterial content significantly differed by maternal diabetes status, with the microbiome of the DM group showing higher alpha-diversity than that of no-diabetes or GDM groups. No global difference was found between babies delivered vaginally versus via Cesarean-section. Regression analysis showed that the most robust predictor for the meconium microbiota composition was the maternal diabetes status that preceded pregnancy. Specifically, Bacteroidetes (phyla) and Parabacteriodes (genus) were enriched in the meconium in the DM group compared to the no-diabetes group.
Our study provides evidence that meconium contains diversified microbiota and is not affected by the mode of delivery. It also suggests that the meconium microbiome of infants born to mothers with DM is enriched for the same bacterial taxa as those reported in the fecal microbiome of adult DM patients.
Sagittal craniosynostosis is the most common form of craniosynostosis, affecting approximately one of 5,000 newborns. We conducted the first genome-wide association study (GWAS) for non-syndromic sagittal craniosynostosis (sNSC) using 130 non-Hispanic white (NHW) case-parent trios. Robust associations were observed in a 120 kb region downstream of BMP2, flanked by rs1884302 (P = 1.13 × 10−14; odds ratio [OR] = 4.58) and rs6140226 (P = 3.40 × 10−11; OR = 0.24) and within a 167 kb region of BBS9 between rs10262453 (P = 1.61 × 10−10; OR=0.19) and rs17724206 (P = 1.50 × 10−8; OR = 0.22). We replicated the associations to both loci [rs1884302 (P = 4.39 × 10−31); rs10262453 (P = 3.50 × 10−14)] in an independent NHW population of 172 unrelated sNSC probands and 548 controls. Both BMP2 and BBS9 are genes with a role in skeletal development warranting functional studies to further understand the etiology of sNSC.
genome-wide association study; non-syndromic sagittal craniosynostosis; BMP2; BBS9; meta-analysis; nonsyndromic
During pregnancy, fetal cells cross into the maternal organs where they reside postpartum. Evidence from multiple laboratories suggests that these microchimeric fetal cells contribute to maternal tissue repair after injury. In mouse models, most injury experiments are performed during pregnancy; however, in a clinical setting most injuries or diseases occur postpartum. Therefore, experiments using animal models should be designed to address questions in the time period following delivery. In order to provide a baseline for such experiments, we analyzed the natural history of fetal cells in the postpartum maternal organs. Female C57BL/6J mice were mated to males homozygous for the enhanced green fluorescent protein gene. Fetal cells in the maternal lungs and bone marrow were identified by their green fluorescence using in a high-speed flow cytometer and their counts were compared between the lung and bone marrow. Spearman correlation analysis was used to identify relationships between the duration of time postpartum and the cell counts and ratio of live and dead cells. Our results show that fetal cells persist in these organs until at least three months postpartum in healthy female mice. We show a two-stage decline, with an initial two and a half-week rapid clearance followed by a trend of gradual decrease. Additionally, an increase in the ratio of live to dead cells within the lung over time suggests that these cells may replicate in vivo. The results presented here will inform the design of future experiments and may have implications for women’s health.
microchimerism; fetal cell trafficking; pregnancy; postpartum; green fluorescent protein; lungs; bone marrow; flow cytometry; mouse
Age-related macular degeneration (AMD) is the most common cause of incurable visual impairment in high-income countries. Previous studies report inconsistent associations between AMD and apolipoprotein E (APOE), a lipid transport protein involved in low-density cholesterol modulation. Potential interaction between APOE and sex, and smoking status, has been reported. We present a pooled analysis (n=21,160) demonstrating associations between late AMD and APOε4 (OR=0.72 per haplotype; CI: 0.65–0.74; P=4.41×10−11) and APOε2 (OR=1.83 for homozygote carriers; CI: 1.04–3.23; P=0.04), following adjustment for age-group and sex within each study and smoking status. No evidence of interaction between APOE and sex or smoking was found. Ever smokers had significant increased risk relative to never smokers for both neovascular (OR=1.54; CI: 1.38–1.72; P=2.8×10−15) and atrophic (OR=1.38; CI: 1.18–1.61; P=3.37×10−5) AMD but not early AMD (OR=0.94; CI: 0.86–1.03; P=0.16), implicating smoking as a major contributing factor to disease progression from early signs to the visually disabling late forms. Extended haplotype analysis incorporating rs405509 did not identify additional risks beyondε2 and ε4 haplotypes. Our expanded analysis substantially improves our understanding of the association between the APOE locus and AMD. It further provides evidence supporting the role of cholesterol modulation, and low-density cholesterol specifically, in AMD disease etiology.
age-related macular degeneration; AMD; apolipoprotein E; APOE; case-control association study
The relationship between obesity, diabetes, hyperlipidemia, hypertension, kidney disease and cardiovascular disease (CVD) is established when looked at from a clinical, epidemiological or pathophysiological perspective. Yet, when viewed from a genetic perspective, there is comparatively little data synthesis that these conditions have an underlying relationship. We sought to investigate the overlap of genetic variants independently associated with each of these commonly co-existing conditions from the NHGRI genome-wide association study (GWAS) catalog, in an attempt to replicate the established notion of shared pathophysiology and risk. We used pathway-based analyses to detect subsets of pleiotropic genes involved in similar biological processes. We identified 107 eligible GWAS studies related to CVD and its established comorbidities and risk factors and assigned genes that correspond to the associated signals based on their position. We found 44 positional genes shared across at least two CVD-related phenotypes that independently recreated the established relationship between the six phenotypes, but only if studies representing non-European populations were included. Seven genes revealed pleiotropy across three or more phenotypes, mostly related to lipid transport and metabolism. Yet, many genes had no relationship to each other or to genes with established functional connection. Whilst we successfully reproduced established relationships between CVD risk factors using GWAS findings, interpretation of biological pathways involved in the observed pleiotropy was limited. Further studies linking genetic variation to gene expression, as well as describing novel biological pathways will be needed to take full advantage of GWAS results.
The objective of this study was to determine if fetal-maternal cell trafficking is affected by maternal immune competence and/or parental background strain using fluorescence-activated cell sorting (FACS). In our experience the sensitivity of FACS allows for the detection of 5 fetal in 107 maternal cells and assessment of cell surface phenotype. Wild-type C57BL/6J (n=18), FVB/NJ (n=15), and immunodeficient B6129S7-Rag1tm1Mom/J (n=16) female mice were mated to C57BL/6J males homozygous for the green fluorescent protein (GFP) transgene. Single cell suspensions of maternal lung, liver, spleen, bone marrow, and blood were analyzed between late gestation (day e16–18) and one day post-partum for the number of GFP-positive fetal cells in relation to 107 maternal cells and the percentage of GFP-positive cells that expressed the surface markers CD11b, CD29, CD34, CD44, or CD105. The highest relative proportions of GFP-positive fetal cells were observed in maternal lungs and livers from immunocompetent allogenic females. Among congenic matings, fetal cell microchimerism was higher in immunodeficient compared with immunocompetent females. Maternal strain and strain differences between the mother and father statistically significantly affected both the numbers of fetal cells and the relative distribution of cell types in maternal organs. The highest relative proportion of fetal cells was observed in allogenic matings with immunocompetent females. Since allogenic matings are more similar to those that occur in humans, future studies using animal models of microchimerism should consider incorporating this type of experimental design.
fetal cell trafficking; mouse model; background strain
The importance of lifestyle intervention for the prevention and treatment of type 2 diabetes (T2D) has been underscored by the limited benefit of pharmacologic therapies. We sought to determine whether genetic variants that contribute to T2D risk modify the response of weight and waist circumference to an intensive lifestyle intervention (ILI) in patients with obesity and T2D. Look AHEAD (Action for Health in Diabetes) is a randomized clinical trial comparing an ILI with a control condition on the risk of cardiovascular disease in overweight adults with T2D. We analyzed 28 single-nucleotide polymorphisms (SNPs) at/near 17 T2D-susceptibility genes in 3,903 consented participants. We genetically characterized the cohort by assessing whether T2D-susceptibility loci were overrepresented compared with a nondiabetic community-based cohort (N = 1,016). We evaluated the association of individual variants and a composite genetic risk score (GRS) with anthropometric traits at baseline and after 1-year of intervention. Look AHEAD subjects carried more T2D-susceptibility alleles than the control population. At baseline, TCF7L2 risk alleles and the highest GRS were associated with lower BMI and waist circumference. Nominally significant genotype-by-intervention interactions were detected for 1-year change in waist circumference with JAZF1, MTNR1B, and IRS1, and BMI with JAZF1. Highest GRS was associated with a greater reduction in waist circumference at year 1, although the variance in change attributable to the GRS was small. This study shows that the genetic burden associated with T2D risk does not undermine the effect of lifestyle intervention and suggests the existence of additional genomic regions, distinct from the T2D-susceptibility loci, which may enhance or mitigate weight loss.
Variation in the apolipoprotein E gene (APOE) has been reported to be associated with longevity in humans. The authors assessed the allelic distribution of APOE isoforms ε2, ε3, and ε4 among 10,623 participants from 15 case-control and cohort studies of age-related macular degeneration (AMD) in populations of European ancestry (study dates ranged from 1990 to 2009). The authors included only the 10,623 control subjects from these studies who were classified as having no evidence of AMD, since variation within the APOE gene has previously been associated with AMD. In an analysis stratified by study center, gender, and smoking status, there was a decreasing frequency of the APOE ε4 isoform with increasing age (χ2 for trend = 14.9 (1 df); P = 0.0001), with a concomitant increase in the ε3 isoform (χ2 for trend = 11.3 (1 df); P = 0.001). The association with age was strongest in ε4 homozygotes; the frequency of ε4 homozygosity decreased from 2.7% for participants aged 60 years or less to 0.8% for those over age 85 years, while the proportion of participants with the ε3/ε4 genotype decreased from 26.8% to 17.5% across the same age range. Gender had no significant effect on the isoform frequencies. This study provides strong support for an association of the APOE gene with human longevity.
aged; apolipoprotein E2; apolipoprotein E3; apolipoprotein E4; apolipoproteins E; longevity; meta-analysis; multicenter study
Apolipoprotein E (APOE) has been studied for its potential role in osteoporosis risk. It is hypothesized that genetic variation at APOE locus, known as E2, E3, and E4, may modulate bone mineral density (BMD) through its effects on lipoproteins and vitamin K transport. The purpose of this study was to determine the association of the APOE-E4 gene polymorphism with bone-related phenotypes.
We conducted a meta-analysis that combined newly-analyzed individual data from two community-based cohorts, the Framingham Offspring Study (N=1,495) and the Vitamin K Clinical Trial (N=377), with fifteen other eligible published reports. Bone phenotypes included BMD measurements of the hip (total hip and trochanteric and femoral neck sites) and lumbar spine (from the L2 to L4 vertebrae) and prevalence or incidence of vertebral, hip and other fractures.
In sex-pooled analyses, APOE4 carriers had a 0.018 g/cm2 lower weighted mean trochanteric BMD than non carriers (p=0.0002) with no evidence for between-study heterogeneity. A significant association was also detected with lumbar spine BMD (p=0.006); however, inter-study heterogeneity was observed. Associations with lumbar spine and trochanteric BMD were observed predominantly in women and became less significant in meta-regression (p=0.055 and 0.01, respectively). There were no consistent associations of APOE4 genotype with BMD at other skeletal sites or with fracture risk.
Based on these findings, there is insufficient evidence to support a strong and consistent association of the APOE genotype with BMD and fracture incidence.
Apolipoprotein E; BMD; Fracture; meta-analysis; polymorphism
In order for DNA biobanks to be a valuable reservoir of genetic information, large numbers of participants from all racial and ethnic backgrounds need to be recruited. This study explored reasons for participating in a new biobank among primarily Hispanic and African American individuals, as well as their general attitudes towards genetic research, and their views on obtaining genetic tests. Focus groups were conducted with Mount Sinai Biobank participants recruited from predominantly lower income, minority communities. The topic guide included questions on The Mount Sinai Biobank, genetic research, and genetic testing. All focus groups were audio recorded, transcribed, and analyzed using thematic analysis. The six focus groups comprised 43 participants: 39 females and four males, aged 27–76 years, with a median household income category of $20,000–$39,999. Twenty-one participants were Hispanic, 20 African American, one Asian, and one White. Participants’ reasons for participating in the biobank included altruism, personal and family benefit, and general curiosity. Although there was evidence of conflation between genetic research and genetic testing, most participants held positive views of genetic research and expressed interest in receiving personal genetic test results. Participants wanted to learn more about genetic research and suggested various venues such as health fairs for disseminating information. Participation in biobanks by racial and ethnic minorities is apparently driven by altruism, and desire for personal or collective health benefits. Participants had generally positive attitudes, limited understanding of genetics and genetic research, and made useful suggestions regarding information dissemination mechanisms.
African American; DNA biobank; Focus groups; Hispanics; Motives
Elevated triglyceride levels are a risk factor for cardiovascular disease. Angiopoietin-like protein 4 (Angptl4) is a metabolic factor that raises plasma triglyceride levels by inhibiting lipoprotein lipase (LPL). In non-diabetic individuals, the ANGPTL4 coding variant E40K has been associated with lower plasma triglyceride levels while the T266M variant has been associated with more modest effects on triglyceride metabolism. The objective of this study was to determine whether ANGPTL4 E40K and T266M are associated with triglyceride levels in the setting of obesity and T2D, and whether modification of triglyceride levels by these genetic variants is altered by a lifestyle intervention designed to treat T2D.
The association of ANGPTL4 E40K and T266M with fasting triglyceride levels was investigated in 2,601 participants from the Look AHEAD Clinical Trial, all of whom had T2D and were at least overweight. Further, we tested for an interaction between genotype and treatment effects on triglyceride levels.
Among non-Hispanic White Look AHEAD participants, ANGPTL4 K40 carriers had mean triglyceride levels of 1.61 ± 0.62 mmol/L, 0.33 mmol/L lower than E40 homozygotes (p = 0.001). Individuals homozygous for the minor M266 allele (MAF 30%) had triglyceride levels of 1.75 ± 0.58 mmol/L, 0.24 mmol/L lower than T266 homozygotes (p = 0.002). The association of the M266 with triglycerides remained significant even after removing K40 carriers from the analysis (p = 0.002). There was no interaction between the weight loss intervention and genotype on triglyceride levels.
This is the first study to demonstrate that the ANGPTL4 E40K and T266M variants are associated with lower triglyceride levels in the setting of T2D. In addition, our findings demonstrate that ANGPTL4 genotype status does not alter triglyceride response to a lifestyle intervention in the Look AHEAD study.
Crohn's disease (CD) has the highest prevalence among individuals of Ashkenazi Jewish (AJ) descent compared to non-Jewish Caucasian populations (NJ). We evaluated a set of well-established CD-susceptibility variants to determine if they can explain the increased CD risk in the AJ population.
We recruited 369 AJ CD patients and 503 AJ controls, genotyped 22 single nucleotide polymorphisms (SNPs) at or near 10 CD-associated genes, NOD2, IL23R, IRGM, ATG16L1, PTGER4, NKX2-3, IL12B, PTPN2, TNFSF15 and STAT3, and assessed their association with CD status. We generated genetic scores based on the risk allele count alone and the risk allele count weighed by the effect size, and evaluated their predictive value.
Three NOD2 SNPs, two IL23R SNPs, and one SNP each at IRGM and PTGER4 were independently associated with CD risk. Carriage of 7 or more copies of these risk alleles or the weighted genetic risk score of 7 or greater correctly classified 92% (allelic count score) and 83% (weighted score) of the controls; however, only 29% and 47% of the cases were identified as having the disease, respectively. This cutoff was associated with a >4-fold increased disease risk (p < 10e-16).
CD-associated genetic risks were similar to those reported in NJ population and are unlikely to explain the excess prevalence of the disease in AJ individuals. These results support the existence of novel, yet unidentified, genetic variants unique to this population. Understanding of ethnic and racial differences in disease susceptibility may help unravel the pathogenesis of CD leading to new personalized diagnostic and therapeutic approaches.
Crohn's Disease; Ashkenazi Jewish; genetic risk score
CYP4F2*3 (p.V433M) has been associated with higher warfarin dose requirements; however, its frequency, like other CYP2C9 and VKORC1 variants, has not been systematically assessed in major racial/ethnic populations. Thus, we determined the individual and combined frequencies of important CYP2C9, VKORC1 and CYP4F2 variants in several racial/ethnic groups.
Materials & methods
Healthy African–American, Asian, Caucasian, Hispanic and Ashkenazi Jewish (AJ) blood donors were genotyped for CYP2C9 (*2, *3, *4, *5, *6, *8, *11 and *13), VKORC1 (g.-1639G>A) and CYP4F2 (*3 [p.V433M] and rs2189784).
The combined frequencies of variant CYP2C9 alleles were 0.133, 0.078, 0.212, 0.178 and 0.212 among African–American, Asian, Caucasian, Hispanic and AJ individuals, respectively. CYP4F2*3 frequencies were prevalent (0.233–0.342) among Asian, Caucasian, Hispanic and AJ individuals, while significantly less frequent among African–Americans (0.117; p < 0.0001). In addition, CYP4F2*3 was in linkage disequilibrium with rs2189784, an allele recently associated with time-to-therapeutic international normalized ratio, among all studied populations. Importantly, 87–95% of Asian, Caucasian, Hispanic and AJ individuals had a variant CYP2C9, VKORC1 and/or CYP4F2*3 allele, compared with only 53% of African–Americans (p < 0.0001).
Compared with other racial/ethnic populations studied, only approximately one in 80 African– Americans were CYP4F2*3 homozygous, indicating that this population would benefit less from dosing algorithms that include this variant. In addition, the unique allele frequency profiles identified among the different populations partly explain why genotype-guided warfarin dosing algorithms perform less well for African–Americans and suggest that other unidentified genetic and/or nongenetic factors that influence warfarin dosage may exist in this population.
allele frequencies; CYP2C9; CYP4F2; pharmacogenetics; VKORC1; warfarin
To determine if chemically-induced miscarriage affects fetomaternal trafficking in a mouse model, we measured the amount of fetal DNA present in various maternal organs by PCR amplification following exposure to lipopolysaccharide (LPS). As the frequency of fetal cells and the number of animals with detectable microchimerism following LPS injection were significantly increased, particularly in lung tissue compared to controls, with no signs of an inflammatory response, we conclude that LPS-induced miscarriage results in increased murine fetomaternal cell trafficking, supporting a relationship between fetal loss and the establishment of fetal cell microchimerism.
Chemically-induced miscarriage significantly increases fetal cell trafficking in murine maternal lung compared to controls, supporting studies in humans that suggest a relationship between fetal loss and microchimerism.
Circulating cell-free DNA and maternal serum analytes are indicators of fetal and placental condition. Little is known about the relationship of these noninvasive markers to each other, particularly in the first trimester. Our goal was to assess the relationship between first and second trimester cell-free DNA levels and maternal serum screening markers.
First and second trimester residual maternal serum samples from 50 women were obtained. First trimester (pregnancy-associated plasma protein A [PAPP-A] and β-hCG), and second trimester serum analytes (β-hCG, alpha-fetoprotein [AFP], unconjugated estriol and inhibin A) had been measured at the time of sample receipt. All fetuses were male, as confirmed by birth records. Cell-free DNA was extracted and measured by real-time quantitative polymerase chain reaction (PCR) amplification using glyceraldehyde phosphate dehydrogenase (GAPDH) and DYS1 as markers of total DNA and fetal DNA, respectively. Determination of linear associations between first and second trimester serum markers and cell-free DNA levels using Pearson correlations was performed.
Statistically significant correlations between first trimester PAPP-A multiples of the median (MoMs) and both total (r=0.36, p=0.016) and fetal (r= 0.41, p=0.006) DNA in the first trimester were observed. There were no significant correlations between first trimester serum hCG or any second trimester serum marker with DNA levels.
Correlation between serum PAPP-A and first trimester circulating cell-free fetal and total DNA levels is a novel finding. PAPP-A is a glycoprotein of placental origin, and its correlation to cell-free fetal DNA in maternal serum suggests a common tissue origin, through apoptosis of placental cells. However, since PAPP-A and cell-free DNA were only marginally correlated and cell-free DNA can be reliably detected in the first trimester, the addition of cell-free DNA to serum screening strategies may be helpful in predicting adverse pregnancy outcome.
Cell-free fetal DNA (cffDNA) in maternal plasma results from degradation of fetal and/or placental cells. Our objective was to determine if chorionic villus sampling (CVS) causes increased release of fetal and/or maternal DNA.
Fifty-two pregnant women were recruited prior to CVS, performed for clinical indications, at 10 5/7 to 13 2/7 weeks. Maternal blood was collected before and within 15 minutes after CVS. cffDNA was extracted from plasma. Real-time polymerase chain reaction (PCR) amplification of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and the Y chromosome sequence DYS1 were used as measures of total and fetal DNA, respectively. All samples were analyzed in triplicate without knowledge of fetal gender.
Sensitivity of DYS1 detection in male fetuses was 100% (n=30); specificity in female fetuses was 100% (n=22). While a majority of women had >50% post-procedure increases in both fetal and total DNA, some showed post-procedure decreases. However, overall median proportional increases were not statistically significant. Gestational age (GA), placental location, and individual CVS operator did not correlate with changes in DNA levels.
While there were no statistically significant overall changes in DNA levels after CVS, as-yet undiscovered variables may influence the extent of post-procedure release of cell-free DNA in the circulation of pregnant women.
CVS; cell-free DNA; prenatal diagnosis
Depression associated with low plasma Amyloid-β peptide 42 (Aβ42) leading to a high ratio of Aβ40/Aβ42, a biomarker of Alzheimer’s disease (AD), may represent a unique depression subtype. The relationship between low plasma Aβ42 in depression and the major risk factor of AD, Apolipoprotein E4 (ApoE4), is unknown. With the goal of clarifying this relationship, we analyzed 1060 homebound elders with ApoE characterization and depression status in a cross-sectional study. Plasma Aβ40 and Aβ42 were measured, and cognition were evaluated. In the absence of the ApoE4 allele, depressed subjects had lower plasma Aβ42 [median (Q1, Q3): 17.1 (11.6, 27.8) vs. 20.2 (12.9, 32.9) pg/ml, P = 0.006], a higher Aβ40/Aβ42 ratio [median (Q1, Q3): 7.1 (4.6, 11.3) vs. 6.9 (3.4, 9.7), P = 0.03], and lower cognitive function (mean ± SD of Mini-Mental State Examination: 24.5 ± 3.1 vs. 25.5 ± 3.3, P < 0.0001) than those without depression. In contrast, these relationships were not observed in the presence of ApoE4. Instead, regardless the depression status ApoE4 carriers had lower plasma Aβ42 and a higher Aβ40/Aβ42 ratio than non-ApoE4 carriers. Using multivariate logistic regression, it was found that depression was not associated with ApoE4 allele, but with the interaction between plasma Aβ42 and ApoE4 (OR = 3.94, 95% CI = 1.50, 10.33, P = 0.005), denoting low plasma Aβ42 in the absence of ApoE4. Both ApoE4 carriers and non-ApoE4 carriers with depression had lower Aβ42 and a higher Aβ40/Aβ42 ratio in plasma compared to non-ApoE4 carriers without depression in the homebound elderly. Since a combination of low plasma Aβ42 and high plasma Aβ40 has been shown to increase the risk of AD in two large cohort studies, amyloid-associated depression shown in this study may suggest a risk factor of AD in the absence of ApoE4.
Background & Aims
Hepatopulmonary syndrome (HPS) affects 10%–30% of patients with cirrhosis and portal hypertension and significantly increases mortality. Studies in experimental models indicate that pulmonary angiogenesis contributes to the development of HPS, but pathogenesis in humans is poorly understood. We investigated genetic risk factors for HPS in patients with advanced liver disease.
We performed a multicenter case-control study of patients with cirrhosis being evaluated for liver transplantation. Cases had an alveolar-arterial oxygen gradient ≥15 mm Hg (or ≥20 mm Hg if age > 64 years) and contrast echocardiography with late appearance of microbubbles after venous injection of agitated saline (intrapulmonary vasodilatation); controls did not meet both criteria for case status. The study sample included 59 cases and 126 controls. We genotyped 1086 common single nucleotide polymorphisms (SNPs) in 94 candidate genes.
Forty-two SNPs in 21 genes were significantly associated with HPS after adjustments for race and smoking. Eight genes had at least 2 SNPs associated with disease: CAV3, ENG, NOX4, ESR2, VWF, RUNX1, COL18A1, and TIE1. For example, rs237872 in CAV3 showed an odds ratio of 2.75 (95% confidence interval: 1.65–4.60, P =.0001) and rs4837192 in ENG showed an odds ratio of 0.35 (95% confidence interval: 0.14–0.89, P =.027). Furthermore, variation in CAV3 and RUNX1 was associated with HPS in gene-based analyses.
Polymorphisms in genes involved in the regulation of angiogenesis are associated with the risk of HPS. Further investigation of these biologic pathways might elucidate the mechanisms that mediate the development of HPS in certain patients with severe liver disease.
Genetic Polymorphism; Portal Hypertension
To better understand fetomaternal cell trafficking during pregnancy, we used a mouse model to determine the cell surface markers expressed on fetal cells, based on the hypothesis that fetal progenitor cells have the capacity to repair maternal organs, whereas more differentiated cells might initiate graft versus host disease. Wild-type females were mated to either homozygous or hemizygous transgenic males and euthanized in the peripartum period. Using dual color flow cytometry, we analyzed fetal transgene positive cells for the presence of nine markers (ITGAM, ITGB1, PECAM, CD34, CD44, PTPRC, ENG, SLAMF1, and CXCR4) to begin to identify the phenotype and degree of differentiation of fetal cells in nine maternal organs (lung, liver, spleen, blood, bone marrow, kidney, heart, thymus, and brain). Fetal cells were found in all maternal organs following either type of mating, albeit always at a higher frequency following mating with homozygous males. Some organs (e.g., lung and liver) had a wide variety of fetal cell markers present, while other organs (e.g., bone marrow and spleen) had a skewed distribution of fetal cell markers. Fetal cells in the murine pregnant female are diverse. Our results suggest that the fetal cells comprise a mixed population of progenitor and differentiated cells, with different relative proportions in different maternal organs. Future studies will address whether fetal cells cross the placental barrier in a differentiated state or as a homogenous population and subsequently differentiate in target maternal organs.
Fetal cells in the pregnant mouse comprise a mixed population of progenitor and differentiated cells, with different relative proportions in different maternal organs.
differentiation; fetal cell microchimerism; phenotype; pregnancy; trafficking
Rationale: Portopulmonary hypertension (PPHTN) occurs in 6% of liver transplant candidates. The pathogenesis of this complication of portal hypertension is poorly understood.
Objectives: To identify genetic risk factors for PPHTN in patients with advanced liver disease.
Methods: We performed a multicenter case-control study of patients with portal hypertension. Cases had a mean pulmonary artery pressure >25 mm Hg, pulmonary vascular resistance >240 dynes·s−1·cm−5, and pulmonary capillary wedge pressure ≤15 mm Hg. Controls had a right ventricular systolic pressure < 40 mm Hg (if estimated) and normal right-sided cardiac morphology by transthoracic echocardiography. We genotyped 1,079 common single nucleotide polymorphisms (SNPs) in 93 candidate genes in each patient.
Measurements and Main Results: The study sample included 31 cases and 104 controls. Twenty-nine SNPs in 15 candidate genes were associated with the risk of PPHTN (P < 0.05). Multiple SNPs in the genes coding for estrogen receptor 1, aromatase, phosphodiesterase 5, angiopoietin 1, and calcium binding protein A4 were associated with the risk of PPHTN. The biological relevance of one of the aromatase SNPs was supported by an association with plasma estradiol levels.
Conclusions: Genetic variation in estrogen signaling and cell growth regulators is associated with the risk of PPHTN. These biologic pathways may elucidate the mechanism for the development of PPHTN in certain patients with severe liver disease.
genetic polymorphism; portal hypertension; hypertension, pulmonary
To identify a candidate neonatal housekeeping gene and to determine the effects of pH and PaO2 on the stability of newborn gene expression in physiologically hypoxic and acidotic newborn blood.
Quantitative (RT)-PCR amplification was performed for 4 commonly used housekeeping genes (GAPDH, β-actin, cyclophilin, 28S rRNA) on extracted RNA. Blood gas analyses determined pH and PaO2 levels.
Results and Conclusions
β-Actin was least variable and GAPDH was most variable housekeeping gene studied. pH negatively correlated with gene expression levels. PaO2 levels did not significantly affect gene expression. These results inform selection of housekeeping genes for neonatal mRNA research.
Quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR); housekeeping gene; newborn gene expression