ContentClopidogrel, one of the most commonly prescribed medications, is a prodrug requiring CYP450 biotransformation. Data suggest its pharmacologic effect varies based on CYP2C19 genotype, but there is uncertainty regarding the clinical risk imparted by specific genotypes.ObjectiveTo define the risk of major adverse cardiovascular outcomes among carriers of 1 (≈ 26% prevalence in whites) and carriers of 2 (≈ 2% prevalence in whites) reduced-function CYP2C19 genetic variants in patients treated with clopidogrel.Data Sources and Study SelectionA literature search was conducted (January 2000-August 2010) in MEDLINE, Cochrane Database of Systematic Reviews, and EMBASE. Genetic studies were included in which clopidogrel was initiated in predominantly invasively managed patients in a manner consistent with the current guideline recommendations and in which clinical outcomes were ascertained.Data ExtractionInvestigators from 9 studies evaluating CYP2C19 genotype and clinical outcomes in patients treated with clopidogrel contributed the relevant hazard ratios (HRs) and 95% confidence intervals (CIs) for specific cardiovascular outcomes by genotype.ResultsAmong 9685 patients (91.3% who underwent percutaneous coronary intervention and 54.5% who had an acute coronary syndrome), 863 experienced the composite end point of cardiovascular death, myocardial infarction, or stroke; and 84 patients had stent thrombosis among the 5894 evaluated for such. Overall, 71.5% were noncarriers, 26.3% had 1 reduced-function CYP2C19 allele, and 2.2% had 2 reduced-function CYP2C19 alleles. A significantly increased risk of the composite end point was evident in both carriers of 1 (HR, 1.55; 95% CI, 1.11-2.17; P = .01) and 2 (HR, 1.76; 95% CI, 1.24-2.50; P = .002) reduced-function CYP2C19 alleles, as compared with noncarriers. Similarly, there was a significantly increased risk of stent thrombosis in both carriers of 1 (HR, 2.67; 95% CI, 1.69-4.22; P < .0001) and 2 (HR, 3.97; 95% CI, 1.75-9.02; P = .001) CYP2C19 reduced-function alleles, as compared with noncarriers.ConclusionAmong patients treated with clopidogrel for percutaneous coronary intervention, carriage of even 1 reduced-function CYP2C19 allele appears to be associated with a significantly increased risk of major adverse cardiovascular events, particularly stent thrombosis.

Background— The clinical impact of platelet aggregation assessed by point-of-care assays is unknown. We sought to evaluate whether high residual platelet reactivity (RPR) to ADP during clopidogrel therapy, measured by a point-of-care assay, predicts adverse clinical events in acute coronary syndrome patients undergoing percutaneous coronary intervention. Methods and Results— We used the VerifyNow P2Y12 assay (Accumetrics Inc, San Diego, Calif) to determine RPR to ADP in 683 patients with acute coronary syndrome undergoing dual-antiplatelet therapy who underwent percutaneous coronary intervention with bare-metal or drug-eluting stent implantation. All patients received a single 600-mg clopidogrel loading dose followed by 75 mg of clopidogrel daily and 100 to 325 mg of aspirin daily. The end points of the study at follow-up of 12 months were cardiovascular death, nonfatal myocardial infarction (MI), and target-vessel revascularization. At a 12-month follow-up, we found 51 ischemic events (24 cardiovascular deaths [3.5%], 27 nonfatal MIs [3.9%]) and 40 target-vessel revascularizations (5.8%). By receiver operating characteristic curve (ROC) analysis, the optimal cutoff value in predicting 12-month cardiovascular death and nonfatal MI was P2Y12 reaction unit values ≥240. RPR, defined in the presence of P2Y12 reaction unit values above this cutoff, was found to be a significant and independent predictor of cardiovascular death and nonfatal MI in a model that adjusted for cardiovascular risk factors, renal failure, reduced left ventricular ejection fraction, multivessel disease, total stent length, bifurcation lesions, number of lesions treated, type of stent, and use of glycoprotein IIb/IIIa inhibitors (cardiovascular death: hazard ratio 2.55, 95% CI 1.08 to 6.07, P =0.034; nonfatal MI: hazard ratio 3.36, 95% CI 1.49 to 7.58, P =0.004). No significant association was found between high RPR and the risk of target-vessel revascularization. Conclusions— RPR to ADP with clopidogrel therapy, measured by the point-of-care assay VerifyNow P2Y12, is able to detect acute coronary syndrome patients at risk of 12-month cardiovascular death and nonfatal MI. The optimal cutoff value was identified as being 240 P2Y12 reaction units.

Several studies have shown that high residual platelet reactivity during clopidogrel treatment is predictive of major cardiovascular events in patients undergoing percutaneous coronary intervention (PCI).^1-14 However, there is no standardized technique among ex vivo platelet function tests, and in studies using the same platelet function test, cutoff values for high on-treatment platelet reactivity established by receiver operating characteristic curve analysis are variable. Consequently, the hypothesis that the risk of thrombotic events increases markedly above a critical cut point of platelet reactivity on in vitro tests is not yet proven. Moreover, most studies have included heterogeneous populations with short follow-up, and few data exist for patients with acute coronary syndromes (ACS) undergoing an invasive procedure.

Ullrich syndrome is a recessive congenital muscular dystrophy affecting connective tissue and muscle. The molecular basis is unknown. Reverse transcription–PCR amplification performed on RNA extracted from fibroblasts or muscle of three Ullrich patients followed by heteroduplex analysis displayed heteroduplexes in one of the three genes coding for collagen type VI (COL6). In patient A, we detected a homozygous insertion of a C leading to a premature termination codon in the triple-helical domain of COL6A2 mRNA. Both healthy consanguineous parents were carriers. In patient B, we found a deletion of 28 nucleotides because of an A → G substitution at nucleotide −2 of intron 17 causing the activation of a cryptic acceptor site inside exon 18. The second mutation was an exon skipping because of a G → A substitution at nucleotide −1 of intron 23. Both mutations are present in an affected brother. The first mutation is also present in the healthy mother, whereas the second mutation is carried by their healthy father. In patient C, we found only one mutation so far—the same deletion of 28 nucleotides found in patient B. In this case, it was a de novo mutation, as it is absent in her parents. mRNA and protein analysis of patient B showed very low amounts of COL6A2 mRNA and of COL6. A near total absence of COL6 was demonstrated by immunofluorescence in fibroblasts and muscle. Our results demonstrate that Ullrich syndrome is caused by recessive mutations leading to a severe reduction of COL6.

We developed a novel software tool, EXCAVATOR, for the detection of copy number variants (CNVs) from whole-exome sequencing data. EXCAVATOR combines a three-step normalization procedure with a novel heterogeneous hidden Markov model algorithm and a calling method that classifies genomic regions into five copy number states. We validate EXCAVATOR on three datasets and compare the results with three other methods. These analyses show that EXCAVATOR outperforms the other methods and is therefore a valuable tool for the investigation of CNVs in largescale projects, as well as in clinical research and diagnostics. EXCAVATOR is freely available at http://sourceforge.net/projects/excavatortool/.