Transcriptomics in Twins Separates Genetic From Environmental Effects on Gene Expression and Blood Pressure
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See related article, pp 457–464
Identification of all of the genes differentially expressed in essential hypertension is highly relevant to elucidation of the mechanisms involved in this complex polygenic condition. Key to this includes the tissues investigated, the genes differentially expressed in each, and sorting out whether the differences in expression in hypertension stem from (1) polymorphism(s) in regulatory DNA affecting transcription of the gene, (2) the expression change being a downstream effect of the latter, (3) a response to an environmental factor, (4) a counter-regulatory response to the elevated blood pressure (BP), or (5) another factor driving both the BP response and gene expression. Although any simple straightforward study documenting transcriptome-wide expression changes should identify the major genes that are differentially expressed in a particular tissue in hypertension, such data are, by themselves, unable to discriminate between each of the aforementioned possibilities.
In the current issue of Hypertension, Huang et al1 at Augusta University, University of Helsinki, the National Heart, Lung, and Blood Institute’s Framingham Heart Study, and University of Mississippi performed a transcriptome-wide analysis of peripheral blood leukocytes of 391 twins (57% monozygous) from the Finnish Twin Cohort study, and a replication study involving the Framingham cohort, looking for transcripts whose expression was associated with BP.1
Although this study is not the first to use peripheral blood leukocytes to determine such transcriptome-wide expression differences, it not only represents an important confirmation but also distinguishes genetic and environmental influences.
Huang et al1 refer to 2 previous blood transcriptome-wide expression studies. One, in 2015 by Huan et al,2 found 83 genes whose expression levels correlated with BP (73 with systolic, 31 with diastolic, and 8 with hypertension).2 They found 65 were positively correlated with BP traits and 8 were negatively correlated. After adjustment for …