In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.

[EX Q]: Context: Collagenous colitis (CC) is a major cause of chronic non-bloody diarrhoea, particularly in the elderly female population. The aetiology of CC is unknown, and still poor is the understanding of its pathogenesis. This possibly involves dysregulated inflammation and immune-mediated reactions in genetically predisposed individuals, but the contribution of genetic factors to CC is underinvestigated. We systematically tested immune-related genes known to impact the risk of several autoimmune diseases for their potential CC-predisposing role.', 'Three independent cohorts of histologically confirmed CC cases (N=314) and controls (N=4299) from Sweden and Germany were included in a 2-step association analysis. Immunochip and targeted single nucleotide polymorphism (SNP) genotype data were produced, respectively, for discovery and replication purposes. Classical human leucocyte antigen (HLA) variants at 2-digit and 4-digit resolution were obtained via imputation from single marker genotypes. SNPs and HLA variants passing quality control filters were tested for association with CC with logistic regression adjusting for age, sex and country of origin.', 'Forty-two markers gave rise to genome-wide significant association signals, all contained within the HLA region on chromosome 6 (best p=4.2×10\Question: Does dense genotyping of immune-related loci identify HLA variants associated with increased risk of collagenous colitis?
[EX A]: HLA genotype associates with CC, thus implicating HLA-related immune mechanisms in its pathogenesis.

[EX Q]: Context: Although the C5 variant of cholinesterase is known to be a cause of hypercholinesterasemia, the pathophysiological significance of the C5 variant and the C5 variant-related hypercholinesterasemia in cardiovascular diseases remain unclear. The present study aimed to clarify the pathophysiological significance of the C5 variant as a risk or protective factor for coronary artery disease (CAD) in patients with severe hypercholinesterasemia.', 'Severe hypercholinesterasemia was defined as serum cholinesterase (ChE) activity >= 450 IU/L (>= 2.0 SD). We screened 11,648 consecutive outpatients between 2005 and 2011 at Toho University, Sakura Medical Center. In patients with severe hypercholinesterasemia, phenotyping of the C5 variant was conducted using polyacrylamide gel electrophoresis and alpha-naphthyl butyrate staining.', '157 subjects (1.4% of 11,648 outpatients screened) were diagnosed with severe hypercholinesterasemia (mean serum ChE activity 574 ± 109 IU/L), and the frequency of the C5 variant was 45.2%. Subjects with the C5 variant had higher age, lower body mass index, milder dyslipidemia and liver dysfunction, and lower rates of hypertension and CAD compared with subjects without the C5 variant. Multivariate logistic regression model demonstrated that the presence of C5 variant independently lowered the risk of CAD, with odds ratio 0.071 (95% confidence interval (CI) 0.007 - 0.763, p = 0.029).\Question: Is c5 variant associated with decreased risk of coronary artery disease in outpatients with severe hypercholinesterasemia?
[EX A]: The prevalence of the C5 variant was relatively high, and the C5 variant is associated with decreased risk of CAD in outpatients with severe hypercholinesterasemia.

[EX Q]: Context: To date, cardiac catheterization and endomyocardial biopsy have been considered the "gold standard" for rejection surveillance after heart transplantation. Factors such as patient size (i.e., infant transplantation), loss of vascular access after repeated catheterizations, and anesthesia requirements all present unique problems and risks related to pediatric rejection surveillance. Therefore, additional methods to monitor for rejection in a non-invasive, reliable and frequent manner have been sought. We studied the utility of echocardiographic measurement of the left ventricular myocardial performance index (LVMPI), a reproducible measure of combined systolic and diastolic performance, in pediatric heart transplant recipients as a method of identifying acute rejection.', 'Two-dimensional/Doppler echocardiographic studies (n = 36) were performed on 21 cardiac transplant patients (ages 6.2 to 21.9 years) at the time of endomyocardial biopsy. The LVMPI, the sum of the isovolumic contraction time and isovolumic relaxation time divided by aortic ejection time, was determined at each study, as well as other echocardiographic measures of systolic and diastolic function. Patients were grouped by concurrent histologic rejection grade and the results compared between groups.', 'Significant differences in LVMPI (p < 0.001) were noted between patients with no rejection (Grade 0; n = 23) and those with moderate to severe rejection (Grade 3; n = 5), as well as between those with no rejection and those with focal moderate (Grade 2; n = 8) rejection (p < 0.05). The LVMPI was 0.42 +/- 0.03 (mean +/- SEM) for the group without rejection, 0.57 +/- 0.06 for those with Grade 2 rejection and 0.73 +/- 0.05 for those with Grade 3 rejection. Although 9 of the 23 studies in the non-rejection group had LVMPI values exceeding 0.44 (upper threshold value), 12 of 13 patients in the rejection groups exceeded this threshold. LVMPI >or= 0.64 was associated with significant rejection in all cases in this study (n = 7). No significant differences were noted between groups for left ventricular ejection fraction or shortening fraction, percent septal or posterior wall thickening, left ventricular mass index or mitral valve deceleration time. In addition, for those individual patients with multiple studies, the LVMPI consistently increased with higher rejection grades and decreased after therapy.\Question: Does increased myocardial performance index correlate with biopsy-proven rejection in pediatric heart transplant recipients?
[EX A]:
In this series, increased LVMPI correlated with biopsy-proven rejection, and frequent serial assessments using this technique may provide a relatively sensitive non-invasive means of rejection surveillance after pediatric cardiac transplantation. False positive results may be encountered, likely due to alterations in diastolic function that have been previously observed in transplant recipients.