ABSTRACT
BACKGROUND: Genome-wide association studies have identified several genetic loci associated with variation in resting heart rate in European and Asian populations. No study has evaluated genetic variants associated with heart rate in African Americans. OBJECTIVE: To identify novel genetic variants associated with resting heart rate in African Americans. METHODS: Ten cohort studies participating in the Candidate-gene Association Resource and Continental Origins and Genetic Epidemiology Network consortia performed genome-wide genotyping of single nucleotide polymorphisms (SNPs) and imputed 2,954,965 SNPs using HapMap YRI and CEU panels in 13,372 participants of African ancestry. Each study measured the RR interval (ms) from 10-second resting 12-lead electrocardiograms and estimated RR-SNP associations using covariate-adjusted linear regression. Random-effects meta-analysis was used to combine cohort-specific measures of association and identify genome-wide significant loci (P≤2.5×10(-8)). RESULTS: Fourteen SNPs on chromosome 6q22 exceeded the genome-wide significance threshold. The most significant association was for rs9320841 (+13 ms per minor allele; P = 4.98×10(-15)). This SNP was approximately 350 kb downstream of GJA1, a locus previously identified as harboring SNPs associated with heart rate in Europeans. Adjustment for rs9320841 also attenuated the association between the remaining 13 SNPs in this region and heart rate. In addition, SNPs in MYH6, which have been identified in European genome-wide association study, were associated with similar changes in the resting heart rate as this population of African Americans. CONCLUSIONS: An intergenic region downstream of GJA1 (the gene encoding connexin 43, the major protein of the human myocardial gap junction) and an intragenic region within MYH6 are associated with variation in resting heart rate in African Americans as well as in populations of European and Asian origin.
Subject(s)
Arrhythmias, Cardiac/genetics , Black or African American/genetics , Connexin 43/genetics , Genetic Variation , Genome-Wide Association Study/methods , Heart Rate , Rest/physiology , Adult , Aged , Arrhythmias, Cardiac/ethnology , Arrhythmias, Cardiac/physiopathology , Connexin 43/metabolism , Electrocardiography , Female , Genotype , Humans , Male , Meta-Analysis as Topic , Middle Aged , Polymorphism, Single Nucleotide , United States/epidemiologyABSTRACT
Systemic infection with Malassezia furfur was first reported in 1981 as a specific complication of Intralipid therapy in a neonate. Six additional patients, including three older than 16 years of age, were identified subsequently. All had received prolonged Intralipid infusion through central venous catheters. Pulmonary infection was documented in tissue in three cases, the clinical presentation was characterized by pulmonary infiltrates, fever, and, in the infants, thrombocytopenia. Two subgroups of patients appear to be at the greatest risk for Malassezia infection: neonates with cardiopulmonary disease and adults with severe gastrointestinal disease and immunosuppression. The documentation of pulmonary arterial lipid deposits in vessels that had been infiltrated by Malassezia organisms and the observation of organisms in small pulmonary thromboemboli suggest that these lipophilic and lipid-dependent organisms are introduced into the bloodstream from venous catheters and require high lipid concentrations to proliferate in tissue.
