Genome-wide meta-analysis of systolic blood pressure in children with sickle cell disease

• Published in: PloS one Vol. 8; no. 9; p. e74193
• Main Authors: Bhatnagar, Pallav, Barron-Casella, Emily, Bean, Christopher J, Milton, Jacqueline N, Baldwin, Clinton T, Steinberg, Martin H, Debaun, Michael, Casella, James F, Arking, Dan E
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 13.09.2013; Public Library of Science (PLoS)
• Subjects: Adolescent; African Americans; Age; Anemia, Sickle Cell - complications; Anemia, Sickle Cell - ethnology; Anemia, Sickle Cell - genetics; Anemia, Sickle Cell - physiopathology; Association analysis; Autism; Binding sites; Black or African American; Blood; Blood Pressure; Cerebral infarction; Cerebral Infarction - ethnology; Cerebral Infarction - etiology; Cerebral Infarction - genetics; Cerebral Infarction - physiopathology; Child; Children; Chromosome 11; Complications; Consortia; Dopamine; Dopamine D2 receptors; Dopamine receptors; Female; Gene loci; Genes; Genetic diversity; Genetic Loci; Genetic Predisposition to Disease; Genetic variance; Genome-Wide Association Study; Genomes; Genomics; Hematology; Humans; Hypertension; Hypertension - complications; Hypertension - ethnology; Hypertension - genetics; Hypertension - physiopathology; Infarction; Loci; Male; Medical research; Medicine; Meta-analysis; Modulation; Morbidity; Patients; Pediatric diseases; Pediatrics; Phenotype; Polymorphism, Single Nucleotide; Risk analysis; Risk Factors; Sickle cell anemia; Sickle cell disease; Single-nucleotide polymorphism; Stroke; Studies; United States > US; Maryland; Massachusetts; Baltimore Maryland
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0074193

In pediatric sickle cell disease (SCD) patients, it has been reported that higher systolic blood pressure (SBP) is associated with increased risk of a silent cerebral infarction (SCI). SCI is a major cause of neurologic morbidity in children with SCD, and blood pressure is a potential modulator of clinical manifestations of SCD; however, the risk factors underlying these complications are not well characterized. The aim of this study was to identify genetic variants that influence SBP in an African American population in the setting of SCD, and explore the use of SBP as an endo-phenotype for SCI. We conducted a genome-wide meta-analysis for SBP using two SCD cohorts, as well as a candidate screen based on published SBP loci. A total of 1,617 patients were analyzed, and while no SNP reached genome-wide significance (P-value<5.0 x 10(-8)), a number of suggestive candidate loci were identified. The most significant SNP, rs7952106 (P-value=8.57 x 10(-7)), was in the DRD2 locus on chromosome 11. In a gene-based association analysis, MIR4301 (micro-RNA4301), which resides in an intron of DRD2, was the most significant gene (P-value=5.2 x 10(-5)). Examining 27 of the previously reported SBP associated SNPs, 4 SNPs were nominally significant. A genetic risk score was constructed to assess the aggregated genetic effect of the published SBP variants, demonstrating a significant association (P=0.05). In addition, we also assessed whether these variants are associated with SCI, validating the use of SBP as an endo-phenotype for SCI. Three SNPs were nominally associated, and only rs2357790 (5' CACNB2) was significant for both SBP and SCI. None of these SNPs retained significance after Bonferroni correction. Taken together, our results suggest the importance of DRD2 genetic variation in the modulation of SBP, and extend the aggregated importance of previously reported SNPs in the modulation of SBP in an African American cohort, more specifically in children with SCD.