UK Prescribing Safety Assessment (PSA): The development, implementation and outcomes of a national online prescribing assessment.

AIMS: The United Kingdom (UK) Prescribing Safety Assessment (PSA) is a 2-h online assessment of basic competence to prescribe and supervise the use of medicines. It has been undertaken by students and doctors in UK medical and foundation schools for the past decade. This study describes the academic characteristics and performance of the assessment; longitudinal performance of candidates and schools; stakeholder feedback; and surrogate markers of prescribing safety in UK healthcare practice. METHODS: We reviewed the performance data generated by over 70 000 medical students and 3700 foundation doctors who have participated in the PSA since its inception in 2013. These data were supplemented by Likert scale and free text feedback from candidates and a variety of stakeholder groups. Further data on medication incidents, collected by national reporting systems and the regulatory body, are reported, with permission. RESULTS: We demonstrate the feasibility, high quality and reliability of an online prescribing assessment, uniquely providing a measure of prescribing competence against a national standard. Over 90% of candidates pass the PSA on their first attempt, while a minority are identified for further training and assessment. The pass rate shows some variation between different institutions and between undergraduate and foundation cohorts. Most responders to a national survey agreed that the PSA is a useful instrument for assessing prescribing competence, and an independent review has recommended adding the PSA to the Medical Licensing Assessment. Surrogate markers suggest there has been improvement in prescribing safety in practice, temporally associated with the introduction of the PSA but other factors could be influential too. CONCLUSIONS: The PSA is a practical and cost-effective way of delivering a reliable national assessment of prescribing competence that has educational impact and is supported by the majority of stakeholders. There is a need to develop national systems to identify and report prescribing errors and the harm they cause, enabling the impact of educational interventions to be measured.

British South Asian ancestry participants views of pharmacogenomics clinical implementation and research: a thematic analysis.

BACKGROUND: South Asian ancestry populations are underrepresented in genomic studies and therapeutics trials. British South Asians suffer from multi-morbidity leading to polypharmacy. Our objective was to elucidate British South Asian ancestry community perspectives on pharmacogenomic implementation and sharing pharmacogenomic clinical data for research. METHODS: Four focus groups were conducted (9-12 participants in each). Two groups were mixed gender, while one group was male only and one was female only. Simultaneous interpretation was available to participants in Urdu and Bengali. Focus groups were recorded and abridged transcription and thematic analysis were undertaken. RESULTS: There were 42 participants, 64% female. 26% were born in the UK or Europe. 52% were born in Bangladesh and 17% in Pakistan. 36% reported university level education. Implementation of pharmacogenomics was perceived to be beneficial to individuals but pose a risk of overburdening resource limited systems. Pharmacogenomic research was perceived to be beneficial to the community, with concerns about data privacy and misuse. Data sharing was desirable if the researchers did not have a financial stake, and benefits would be shared. Trust was the key condition for the acceptability of both clinical implementation and research. Trust was linked with medication compliance. Education, outreach, and communication facilitate trust. CONCLUSIONS (SIGNIFICANCE AND IMPACT OF THE STUDY): Pharmacogenomics implementation with appropriate education and communication has the potential to enhance trust and contribute to increased medication compliance. Trust drives data sharing, which would enable enhanced representation in research. Representation in scientific evidence base could cyclically enhance trust and compliance.

Functional filter for whole-genome sequencing data identifies HHT and stress-associated non-coding SMAD4 polyadenylation site variants >5 kb from coding DNA.

Despite whole-genome sequencing (WGS), many cases of single-gene disorders remain unsolved, impeding diagnosis and preventative care for people whose disease-causing variants escape detection. Since early WGS data analytic steps prioritize protein-coding sequences, to simultaneously prioritize variants in non-coding regions rich in transcribed and critical regulatory sequences, we developed GROFFFY, an analytic tool that integrates coordinates for regions with experimental evidence of functionality. Applied to WGS data from solved and unsolved hereditary hemorrhagic telangiectasia (HHT) recruits to the 100,000 Genomes Project, GROFFFY-based filtration reduced the mean number of variants/DNA from 4,867,167 to 21,486, without deleting disease-causal variants. In three unsolved cases (two related), GROFFFY identified ultra-rare deletions within the 3' untranslated region (UTR) of the tumor suppressor SMAD4, where germline loss-of-function alleles cause combined HHT and colonic polyposis (MIM: 175050). Sited >5.4 kb distal to coding DNA, the deletions did not modify or generate microRNA binding sites, but instead disrupted the sequence context of the final cleavage and polyadenylation site necessary for protein production: By iFoldRNA, an AAUAAA-adjacent 16-nucleotide deletion brought the cleavage site into inaccessible neighboring secondary structures, while a 4-nucleotide deletion unfolded the downstream RNA polymerase II roadblock. SMAD4 RNA expression differed to control-derived RNA from resting and cycloheximide-stressed peripheral blood mononuclear cells. Patterns predicted the mutational site for an unrelated HHT/polyposis-affected individual, where a complex insertion was subsequently identified. In conclusion, we describe a functional rare variant type that impacts regulatory systems based on RNA polyadenylation. Extension of coding sequence-focused gene panels is required to capture these variants.

SLCO1B1*5 is protective against non-senile cataracts in cohort prescribed statins: analysis in a British-South Asian cohort.

BACKGROUND: Reported association between statin use and cataract risk is controversial. The SLCO1B1 gene encodes a transport protein responsible for statin clearance. The aim of this study was to investigate a possible association between the SLCO1B1*5 reduced function variant and cataract risk in statin users of South Asian ethnicity. METHODS: The Genes & Health cohort consists of British-Bangladeshi and British-Pakistani participants from East London, Manchester and Bradford, UK. SLCO1B1*5 genotype was assessed with the Illumina GSAMD-24v3-0-EA chip. Medication data from primary care health record linkage was used to compare those who had regularly used statins compared to those who had not. Multivariable logistic regression was used to test for association between statin use and cataracts, adjusting for population characteristics and potential confounders in 36,513 participants. Multivariable logistic regression was used to test association between SLCO1B1*5 heterozygotes or homozygotes and cataracts, in subgroups having been regularly prescribed statins versus not. RESULTS: Statins were prescribed to 35% (12,704) of participants (average age 41 years old, 45% male). Non-senile cataract was diagnosed in 5% (1686) of participants. An apparent association between statins and non-senile cataract (12% in statin users and 0.8% in non-statin users) was negated by inclusion of confounders. In those prescribed a statin, presence of the SLCO1B1*5 genotype was independently associated with a decreased risk of non-senile cataract (OR 0.7 (CI 0.5-0.9, p 0.007)). CONCLUSIONS: Our findings suggest that there is no independent association between statin use and non-senile cataract risk after adjusting for confounders. Among statin users, the SLCO1B1*5 genotype is associated with a 30% risk reduction of non-senile cataracts. Stratification of on-drug cohorts by validated pharmacogenomic variants is a useful tool to support or repudiate adverse drug events in observational cohorts.

Whole-genome sequencing of chronic lymphocytic leukemia identifies subgroups with distinct biological and clinical features.

The value of genome-wide over targeted driver analyses for predicting clinical outcomes of cancer patients is debated. Here, we report the whole-genome sequencing of 485 chronic lymphocytic leukemia patients enrolled in clinical trials as part of the United Kingdom's 100,000 Genomes Project. We identify an extended catalog of recurrent coding and noncoding genetic mutations that represents a source for future studies and provide the most complete high-resolution map of structural variants, copy number changes and global genome features including telomere length, mutational signatures and genomic complexity. We demonstrate the relationship of these features with clinical outcome and show that integration of 186 distinct recurrent genomic alterations defines five genomic subgroups that associate with response to therapy, refining conventional outcome prediction. While requiring independent validation, our findings highlight the potential of whole-genome sequencing to inform future risk stratification in chronic lymphocytic leukemia.

Nuclear-embedded mitochondrial DNA sequences in 66,083 human genomes.

DNA transfer from cytoplasmic organelles to the cell nucleus is a legacy of the endosymbiotic event-the majority of nuclear-mitochondrial segments (NUMTs) are thought to be ancient, preceding human speciation1-3. Here we analyse whole-genome sequences from 66,083 people-including 12,509 people with cancer-and demonstrate the ongoing transfer of mitochondrial DNA into the nucleus, contributing to a complex NUMT landscape. More than 99% of individuals had at least one of 1,637 different NUMTs, with 1 in 8 individuals having an ultra-rare NUMT that is present in less than 0.1% of the population. More than 90% of the extant NUMTs that we evaluated inserted into the nuclear genome after humans diverged from apes. Once embedded, the sequences were no longer under the evolutionary constraint seen within the mitochondrion, and NUMT-specific mutations had a different mutational signature to mitochondrial DNA. De novo NUMTs were observed in the germline once in every 104 births and once in every 103 cancers. NUMTs preferentially involved non-coding mitochondrial DNA, linking transcription and replication to their origin, with nuclear insertion involving multiple mechanisms including double-strand break repair associated with PR domain zinc-finger protein 9 (PRDM9) binding. The frequency of tumour-specific NUMTs differed between cancers, including a probably causal insertion in a myxoid liposarcoma. We found evidence of selection against NUMTs on the basis of size and genomic location, shaping a highly heterogenous and dynamic human NUMT landscape.

Identification and validation of a novel pathogenic variant in GDF2 (BMP9) responsible for hereditary hemorrhagic telangiectasia and pulmonary arteriovenous malformations.

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant multisystemic vascular dysplasia, characterized by arteriovenous malformations (AVMs), mucocutaneous telangiectasia and nosebleeds. HHT is caused by a heterozygous null allele in ACVRL1, ENG, or SMAD4, which encode proteins mediating bone morphogenetic protein (BMP) signaling. Several missense and stop-gain variants identified in GDF2 (encoding BMP9) have been reported to cause a vascular anomaly syndrome similar to HHT, however none of these patients met diagnostic criteria for HHT. HHT families from UK NHS Genomic Medicine Centres were recruited to the Genomics England 100,000 Genomes Project. Whole genome sequencing and tiering protocols identified a novel, heterozygous GDF2 sequence variant in all three affected members of one HHT family who had previously screened negative for ACVRL1, ENG, and SMAD4. All three had nosebleeds and typical HHT telangiectasia, and the proband also had severe pulmonary AVMs from childhood. In vitro studies showed the mutant construct expressed the proprotein but lacked active mature BMP9 dimer, suggesting the mutation disrupts correct cleavage of the protein. Plasma BMP9 levels in the patients were significantly lower than controls. In conclusion, we propose that this heterozygous GDF2 variant is a rare cause of HHT associated with pulmonary AVMs.

The Pharmacogenetics of Statin Therapy on Clinical Events: No Evidence that Genetic Variation Affects Statin Response on Myocardial Infarction.

Background: The pharmacogenetic effect on cardiovascular disease reduction in response to statin treatment has only been assessed in small studies. In a pharmacogenetic genome wide association study (GWAS) analysis within the Genomic Investigation of Statin Therapy (GIST) consortium, we investigated whether genetic variation was associated with the response of statins on cardiovascular disease risk reduction. Methods: The investigated endpoint was incident myocardial infarction (MI) defined as coronary heart disease death and definite and suspect non-fatal MI. For imputed single nucleotide polymorphisms (SNPs), regression analysis was performed on expected allelic dosage and meta-analysed with a fixed-effects model, inverse variance weighted meta-analysis. All SNPs with p-values <5.0 × 10-4 in stage 1 GWAS meta-analysis were selected for further investigation in stage-2. As a secondary analysis, we extracted SNPs from the Stage-1 GWAS meta-analysis results based on predefined hypotheses to possibly modifying the effect of statin therapy on MI. Results: In stage-1 meta-analysis (eight studies, n = 10,769, 4,212 cases), we observed no genome-wide significant results (p < 5.0 × 10-8). A total of 144 genetic variants were followed-up in the second stage (three studies, n = 1,525, 180 cases). In the combined meta-analysis, no genome-wide significant hits were identified. Moreover, none of the look-ups of SNPs known to be associated with either CHD or with statin response to cholesterol levels reached Bonferroni level of significance within our stage-1 meta-analysis. Conclusion: This GWAS analysis did not provide evidence that genetic variation affects statin response on cardiovascular risk reduction. It does not appear likely that genetic testing for predicting effects of statins on clinical events will become a useful tool in clinical practice.

Whole-genome sequencing of patients with rare diseases in a national health system.

Most patients with rare diseases do not receive a molecular diagnosis and the aetiological variants and causative genes for more than half such disorders remain to be discovered1. Here we used whole-genome sequencing (WGS) in a national health system to streamline diagnosis and to discover unknown aetiological variants in the coding and non-coding regions of the genome. We generated WGS data for 13,037 participants, of whom 9,802 had a rare disease, and provided a genetic diagnosis to 1,138 of the 7,065 extensively phenotyped participants. We identified 95 Mendelian associations between genes and rare diseases, of which 11 have been discovered since 2015 and at least 79 are confirmed to be aetiological. By generating WGS data of UK Biobank participants2, we found that rare alleles can explain the presence of some individuals in the tails of a quantitative trait for red blood cells. Finally, we identified four novel non-coding variants that cause disease through the disruption of transcription of ARPC1B, GATA1, LRBA and MPL. Our study demonstrates a synergy by using WGS for diagnosis and aetiological discovery in routine healthcare.

Greater risk of severe COVID-19 in Black, Asian and Minority Ethnic populations is not explained by cardiometabolic, socioeconomic or behavioural factors, or by 25(OH)-vitamin D status: study of 1326 cases from the UK Biobank.

BACKGROUND: We examined whether the greater severity of coronavirus disease 2019 (COVID-19) amongst men and Black, Asian and Minority Ethnic (BAME) individuals is explained by cardiometabolic, socio-economic or behavioural factors. METHODS: We studied 4510 UK Biobank participants tested for COVID-19 (positive, n = 1326). Multivariate logistic regression models including age, sex and ethnicity were used to test whether addition of (1) cardiometabolic factors [diabetes, hypertension, high cholesterol, prior myocardial infarction, smoking and body mass index (BMI)]; (2) 25(OH)-vitamin D; (3) poor diet; (4) Townsend deprivation score; (5) housing (home type, overcrowding) or (6) behavioural factors (sociability, risk taking) attenuated sex/ethnicity associations with COVID-19 status. RESULTS: There was over-representation of men and BAME ethnicities in the COVID-19 positive group. BAME individuals had, on average, poorer cardiometabolic profile, lower 25(OH)-vitamin D, greater material deprivation, and were more likely to live in larger households and in flats/apartments. Male sex, BAME ethnicity, higher BMI, higher Townsend deprivation score and household overcrowding were independently associated with significantly greater odds of COVID-19. The pattern of association was consistent for men and women; cardiometabolic, socio-demographic and behavioural factors did not attenuate sex/ethnicity associations. CONCLUSIONS: In this study, sex and ethnicity differential pattern of COVID-19 was not adequately explained by variations in cardiometabolic factors, 25(OH)-vitamin D levels or socio-economic factors. Factors which underlie ethnic differences in COVID-19 may not be easily captured, and so investigation of alternative biological and genetic susceptibilities as well as more comprehensive assessment of the complex economic, social and behavioural differences should be prioritised.

A blood pressure-associated variant of the SLC39A8 gene influences cellular cadmium accumulation and toxicity.

Genome-wide association studies have revealed a relationship between inter-individual variation in blood pressure and the single nucleotide polymorphism rs13107325 in the SLC39A8 gene. This gene encodes the ZIP8 protein which co-transports divalent metal cations, including heavy metal cadmium, the accumulation of which has been associated with increased blood pressure. The polymorphism results in two variants of ZIP8 with either an alanine (Ala) or a threonine (Thr) at residue 391. We investigated the functional impact of this variant on protein conformation, cadmium transport, activation of signalling pathways and cell viability in relation to blood pressure regulation. Following incubation with cadmium, higher intracellular cadmium was detected in cultured human embryonic kidney cells (HEK293) expressing heterologous ZIP8-Ala391, compared with HEK293 cells expressing heterologous ZIP8-Thr391. This Ala391-associated cadmium accumulation also increased the phosphorylation of the signal transduction molecule ERK2, activation of the transcription factor NFκB, and reduced cell viability. Similarly, vascular endothelial cells with the Ala/Ala genotype had higher intracellular cadmium concentration and lower cell viability than their Ala/Thr counterpart following cadmium exposure. These results indicate that the ZIP8 Ala391-to-Thr391 substitution has an effect on intracellular cadmium accumulation and cell toxicity, providing a potential mechanistic explanation for the association of this genetic variant with blood pressure.

A deleterious gene-by-environment interaction imposed by calcium channel blockers in Marfan syndrome.

Calcium channel blockers (CCBs) are prescribed to patients with Marfan syndrome for prophylaxis against aortic aneurysm progression, despite limited evidence for their efficacy and safety in the disorder. Unexpectedly, Marfan mice treated with CCBs show accelerated aneurysm expansion, rupture, and premature lethality. This effect is both extracellular signal-regulated kinase (ERK1/2) dependent and angiotensin-II type 1 receptor (AT1R) dependent. We have identified protein kinase C beta (PKCß) as a critical mediator of this pathway and demonstrate that the PKCß inhibitor enzastaurin, and the clinically available anti-hypertensive agent hydralazine, both normalize aortic growth in Marfan mice, in association with reduced PKCß and ERK1/2 activation. Furthermore, patients with Marfan syndrome and other forms of inherited thoracic aortic aneurysm taking CCBs display increased risk of aortic dissection and need for aortic surgery, compared to patients on other antihypertensive agents.

Extracellular volume quantification in isolated hypertension - changes at the detectable limits?

BACKGROUND: Diffuse myocardial fibrosis (DMF) is important in cardiovascular disease, however until recently could only be assessed by invasive biopsy. We hypothesised that DMF measured by T1 mapping is elevated in isolated systemic hypertension. METHODS: In a study of well-controlled hypertensive patients from a specialist tertiary centre, 46 hypertensive patients (median age 56, range 21 to 78, 52 % male) and 50 healthy volunteers (median age 45, range 28 to 69, 52 % male) underwent clinical CMR at 1.5 T with T1 mapping (ShMOLLI) using the equilibrium contrast technique for extracellular volume (ECV) quantification. Patients underwent 24-hours Automated Blood Pressure Monitoring (ABPM), echocardiographic assessment of diastolic function, aortic stiffness assessment and measurement of NT-pro-BNP and collagen biomarkers. RESULTS: Late gadolinium enhancement (LGE) revealed significant unexpected underlying pathology in 6 out of 46 patients (13 %; myocardial infarction n = 3; hypertrophic cardiomyopathy (HCM) n = 3); these were subsequently excluded. Limited, non-ischaemic LGE patterns were seen in 11 out of the remaining 40 (28 %) patients. Hypertensives on therapy (mean 2.2 agents) had a mean ABPM of 152/88 mmHg, but only 35 % (14/40) had left ventricular hypertrophy (LVH; LV mass male > 90 g/m(2); female > 78 g/m(2)). Native myocardial T1 was similar in hypertensives and controls (955 ± 30 ms versus 965 ± 38 ms, p = 0.16). The difference in ECV did not reach significance (0.26 ± 0.02 versus 0.27 ± 0.03, p = 0.06). In the subset with LVH, the ECV was significantly higher (0.28 ± 0.03 versus 0.26 ± 0.02, p < 0.001). CONCLUSION: In well-controlled hypertensive patients, conventional CMR discovered significant underlying diseases (chronic infarction, HCM) not detected by echocardiography previously or even during this study. T1 mapping revealed increased diffuse myocardial fibrosis, but the increases were small and only occurred with LVH.

Genome-wide association study of survival from sepsis due to pneumonia: an observational cohort study.

BACKGROUND: Sepsis continues to be a major cause of death, disability, and health-care expenditure worldwide. Despite evidence suggesting that host genetics can influence sepsis outcomes, no specific loci have yet been convincingly replicated. The aim of this study was to identify genetic variants that influence sepsis survival. METHODS: We did a genome-wide association study in three independent cohorts of white adult patients admitted to intensive care units with sepsis, severe sepsis, or septic shock (as defined by the International Consensus Criteria) due to pneumonia or intra-abdominal infection (cohorts 1-3, n=2534 patients). The primary outcome was 28 day survival. Results for the cohort of patients with sepsis due to pneumonia were combined in a meta-analysis of 1553 patients from all three cohorts, of whom 359 died within 28 days of admission to the intensive-care unit. The most significantly associated single nucleotide polymorphisms (SNPs) were genotyped in a further 538 white patients with sepsis due to pneumonia (cohort 4), of whom 106 died. FINDINGS: In the genome-wide meta-analysis of three independent pneumonia cohorts (cohorts 1-3), common variants in the FER gene were strongly associated with survival (p=9·7 × 10(-8)). Further genotyping of the top associated SNP (rs4957796) in the additional cohort (cohort 4) resulted in a combined p value of 5·6 × 10(-8) (odds ratio 0·56, 95% CI 0·45-0·69). In a time-to-event analysis, each allele reduced the mortality over 28 days by 44% (hazard ratio for death 0·56, 95% CI 0·45-0·69; likelihood ratio test p=3·4 × 10(-9), after adjustment for age and stratification by cohort). Mortality was 9·5% in patients carrying the CC genotype, 15·2% in those carrying the TC genotype, and 25·3% in those carrying the TT genotype. No significant genetic associations were identified when patients with sepsis due to pneumonia and intra-abdominal infection were combined. INTERPRETATION: We have identified common variants in the FER gene that associate with a reduced risk of death from sepsis due to pneumonia. The FER gene and associated molecular pathways are potential novel targets for therapy or prevention and candidates for the development of biomarkers for risk stratification. FUNDING: European Commission and the Wellcome Trust.

Protein interaction networks associated with cardiovascular disease and cancer: exploring the effect of bias on shared network properties.

The human network of Protein-Protein Interactions (PPIs) (interactome) provides information on biological systems that can be used to aid prediction of protein function and disease association. As some classes of protein may be the focus of much study, data sets may contain bias, which may affect the results of network analyses. Implicated cancer proteins and proteins including significant known mediators of cardiovascular disease (cvd) display a tendency to play a central role in a previously constructed interactome. However, removing possible bias in the interactome by only considering interactions obtained from non-targeted approaches affects the significance of the findings.

Enhanced vasodilator activity of nitrite in hypertension: critical role for erythrocytic xanthine oxidoreductase and translational potential.

Elevation of circulating nitrite (NO2(-)) levels causes vasodilatation and lowers blood pressure in healthy volunteers. Whether these effects and the underpinning mechanisms persist in hypertension is unknown. Therefore, we investigated the consequences of systemic nitrite elevation in spontaneously hypertensive rats and conducted proof-of-principle studies in patients. Nitrite caused dose-dependent blood pressure-lowering that was profoundly enhanced in spontaneously hypertensive rats versus normotensive Wistar Kyoto controls. This effect was virtually abolished by the xanthine oxidoreductase (XOR) inhibitor, allopurinol, and associated with hypertension-specific XOR-dependent nitrite reductase activity localized to the erythrocyte but not the blood vessel wall. To determine whether these pathways translate to human hypertension, we investigated the effects of elevation of circulating nitrite levels in 15 drug naïve grade 1 hypertensives. To elevate nitrite, we used a dose of dietary nitrate (≈ 3.5 mmol) that elevated nitrite levels ≈ 1.5-fold (P<0.01); a rise shown previously to exert no significant blood pressure-lowering effects in normotensives. This dose caused substantial reductions in systolic (≈ 12 mm Hg) and diastolic blood pressures (P<0.001) and pulse wave velocity (P<0.05); effects associated with elevations in erythrocytic XOR expression and XOR-dependent nitrite reductase activity. Our observations demonstrate the improved efficacy of inorganic nitrate and nitrite in hypertension as a consequence of increased erythrocytic XOR nitrite reductase activity and support the concept of dietary nitrate supplementation as an effective, but simple and inexpensive, antihypertensive strategy.

Genes for blood pressure: an opportunity to understand hypertension.

Hypertension (HTN) is quantitatively the major cardiovascular risk factor and responsible for ∼50% of cardiovascular morbidity and mortality. Blood pressure (BP) is also a classical complex genetic trait with heritability estimates of 30-50%. Although much is known about BP regulation, the intrinsic origin of essential HTN remains obscure although many environmental factors are known. Analyses of rare monogenic syndromes of HTN have focused attention on pathways that involve renal sodium handling, and steroid hormone metabolism including the mineralocorticoid receptor activity. The genetic basis of common essential HTN on the other hand is only just becoming accessible through high-throughput approaches. Unbiased genome-wide analyses of BP genomics have identified 43 genetic variants associated with systolic, diastolic BP, and HTN. It is highly likely based on current findings that there are hundreds of such loci with small effects on BP, opening a perspective on the genetic architecture of BP that was unknown before. It is our hope that the knowledge of these and further loci will lead to improved understanding of BP pathophysiology and to the identification of new targets for drug therapy.

Mutations in the TGF-ß repressor SKI cause Shprintzen-Goldberg syndrome with aortic aneurysm.

Elevated transforming growth factor (TGF)-ß signaling has been implicated in the pathogenesis of syndromic presentations of aortic aneurysm, including Marfan syndrome (MFS) and Loeys-Dietz syndrome (LDS). However, the location and character of many of the causal mutations in LDS intuitively imply diminished TGF-ß signaling. Taken together, these data have engendered controversy regarding the specific role of TGF-ß in disease pathogenesis. Shprintzen-Goldberg syndrome (SGS) has considerable phenotypic overlap with MFS and LDS, including aortic aneurysm. We identified causative variation in ten individuals with SGS in the proto-oncogene SKI, a known repressor of TGF-ß activity. Cultured dermal fibroblasts from affected individuals showed enhanced activation of TGF-ß signaling cascades and higher expression of TGF-ß-responsive genes relative to control cells. Morpholino-induced silencing of SKI paralogs in zebrafish recapitulated abnormalities seen in humans with SGS. These data support the conclusions that increased TGF-ß signaling is the mechanism underlying SGS and that high signaling contributes to multiple syndromic presentations of aortic aneurysm.

Functional analyses of coronary artery disease associated variation on chromosome 9p21 in vascular smooth muscle cells.

Variation on chromosome 9p21 is associated with risk of coronary artery disease (CAD). This genomic region contains the CDKN2A and CDKN2B genes which encode the cell cycle regulators p16(INK4a), p14(ARF) and p15(INK4b) and the ANRIL gene which encodes a non-coding RNA. Vascular smooth muscle cell (VSMC) proliferation plays an important role in the pathogenesis of atherosclerosis which causes CAD. We ascertained whether 9p21 genotype had an influence on CDKN2A/CDKN2B/ANRIL expression levels in VSMCs, VSMC proliferation and VSMC content in atherosclerotic plaques. Immunohistochemical examination showed that VSMCs in atherosclerotic lesions expressed p16(INK4a), p14(ARF) and p15(INK4b). Analyses of primary cultures of VSMCs showed that the 9p21 risk genotype was associated with reduced expression of p16(INK4a), p15(INK4b) and ANRIL (P = 1.2 × 10(-5), 1.4 × 10(-2) and 3.1 × 10(-9)) and with increased VSMC proliferation (P = 1.6 × 10(-2)). Immunohistochemical analyses of atherosclerotic plaques revealed an association of the risk genotype with reduced p15(INK4b) levels in VSMCs (P = 3.7 × 10(-2)) and higher VSMC content (P = 5.6 × 10(-4)) in plaques. The results of this study indicate that the 9p21 variation has an impact on CDKN2A and CDKN2B expression in VSMCs and influences VMSC proliferation, which likely represents an important mechanism for the association between this genetic locus and susceptibility to CAD.