Browsing by Author "Stolz, Andrew A."

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    Reliability of causality assessment for drug, herbal and dietary supplement hepatotoxicity in the Drug-Induced Liver Injury Network (DILIN)
    (Wiley, 2015-05) Hayashi, Paul H.; Barnhart, Huiman X.; Fontana, Robert J.; Chalasani, Naga; Davern, Timothy J.; Talwalkar, Jayant A.; Reddy, K. Rajender; Stolz, Andrew A.; Hoofnagle, Jay H.; Rockey, Don C.; Department of Medicine, IU School of Medicine
    BACKGROUND & AIMS: Because of the lack of objective tests to diagnose drug-induced liver injury (DILI), causality assessment is a matter of debate. Expert opinion is often used in research and industry, but its test-retest reliability is unknown. To determine the test-retest reliability of the expert opinion process used by the Drug-Induced Liver Injury Network (DILIN). METHODS: Three DILIN hepatologists adjudicate suspected hepatotoxicity cases to one of five categories representing levels of likelihood of DILI. Adjudication is based on retrospective assessment of gathered case data that include prospective follow-up information. One hundred randomly selected DILIN cases were re-assessed using the same processes for initial assessment but by three different reviewers in 92% of cases. RESULTS: The median time between assessments was 938 days (range 140-2352). Thirty-one cases involved >1 agent. Weighted kappa statistics for overall case and individual agent category agreement were 0.60 (95% CI: 0.50-0.71) and 0.60 (0.52-0.68) respectively. Overall case adjudications were within one category of each other 93% of the time, while 5% differed by two categories and 2% differed by three categories. Fourteen per cent crossed the 50% threshold of likelihood owing to competing diagnoses or atypical timing between drug exposure and injury. CONCLUSIONS: The DILIN expert opinion causality assessment method has moderate interobserver reliability but very good agreement within one category. A small but important proportion of cases could not be reliably diagnosed as ≥50% likely to be DILI.
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    Under-reporting and Poor Adherence to Monitoring Guidelines for Severe Cases of Isoniazid Hepatotoxicity
    (Elsevier, 2015-09) Hayashi, Paul H.; Fontana, Robert J.; Chalasani, Naga; Stolz, Andrew A.; Talwalker, Jay A.; Navarro, Victor J.; Lee, William M.; Davern, Timothy J.; Kleiner, David E.; Gu, Jiezhun; Hoofnagle, Jay H.; Department of Medicine, IU School of Medicine
    IMPORTANCE: Mutations in known causal Alzheimer disease (AD) genes account for only 1% to 3% of patients and almost all are dominantly inherited. Recessive inheritance of complex phenotypes can be linked to long (>1-megabase [Mb]) runs of homozygosity (ROHs) detectable by single-nucleotide polymorphism (SNP) arrays. OBJECTIVE: To evaluate the association between ROHs and AD in an African American population known to have a risk for AD up to 3 times higher than white individuals. DESIGN, SETTING, AND PARTICIPANTS: Case-control study of a large African American data set previously genotyped on different genome-wide SNP arrays conducted from December 2013 to January 2015. Global and locus-based ROH measurements were analyzed using raw or imputed genotype data. We studied the raw genotypes from 2 case-control subsets grouped based on SNP array: Alzheimer's Disease Genetics Consortium data set (871 cases and 1620 control individuals) and Chicago Health and Aging Project-Indianapolis Ibadan Dementia Study data set (279 cases and 1367 control individuals). We then examined the entire data set using imputed genotypes from 1917 cases and 3858 control individuals. MAIN OUTCOMES AND MEASURES: The ROHs larger than 1 Mb, 2 Mb, or 3 Mb were investigated separately for global burden evaluation, consensus regions, and gene-based analyses. RESULTS: The African American cohort had a low degree of inbreeding (F ~ 0.006). In the Alzheimer's Disease Genetics Consortium data set, we detected a significantly higher proportion of cases with ROHs greater than 2 Mb (P = .004) or greater than 3 Mb (P = .02), as well as a significant 114-kilobase consensus region on chr4q31.3 (empirical P value 2 = .04; ROHs >2 Mb). In the Chicago Health and Aging Project-Indianapolis Ibadan Dementia Study data set, we identified a significant 202-kilobase consensus region on Chr15q24.1 (empirical P value 2 = .02; ROHs >1 Mb) and a cluster of 13 significant genes on Chr3p21.31 (empirical P value 2 = .03; ROHs >3 Mb). A total of 43 of 49 nominally significant genes common for both data sets also mapped to Chr3p21.31. Analyses of imputed SNP data from the entire data set confirmed the association of AD with global ROH measurements (12.38 ROHs >1 Mb in cases vs 12.11 in controls; 2.986 Mb average size of ROHs >2 Mb in cases vs 2.889 Mb in controls; and 22% of cases with ROHs >3 Mb vs 19% of controls) and a gene-cluster on Chr3p21.31 (empirical P value 2 = .006-.04; ROHs >3 Mb). Also, we detected a significant association between AD and CLDN17 (empirical P value 2 = .01; ROHs >1 Mb), encoding a protein from the Claudin family, members of which were previously suggested as AD biomarkers. CONCLUSIONS AND RELEVANCE: To our knowledge, we discovered the first evidence of increased burden of ROHs among patients with AD from an outbred African American population, which could reflect either the cumulative effect of multiple ROHs to AD or the contribution of specific loci harboring recessive mutations and risk haplotypes in a subset of patients. Sequencing is required to uncover AD variants in these individuals.