The National Institutes of Health (NIH) Genotype-Tissue Expression (GTEx) project was designed to evaluate how genetic variation and epigenetic effects influence gene expression in normal tissue.


To ensure that the grossly normal-appearing tissues collected were free from disease, each specimen underwent histologic evaluation.


In total, nearly 30 000 tissue aliquots collected from almost 1000 postmortem donors underwent histologic review by project pathologists, and detailed observations of any abnormalities or lesions present were recorded.


Despite sampling of normal-appearing tissue, in-depth review revealed incidental findings among GTEx samples that included neoplastic, autoimmune, and genetic conditions; the incidence of some of these conditions among GTEx donors differed from those previously reported for other populations. A number of age-related abnormalities observed during histologic review of tissue specimens are also described.


Histologic findings from the GTEx project may serve to improve populational awareness of several conditions and present a unique opportunity for others to explore age- and gender-influenced conditions. Resources from the study, including histologic image and sequencing data, are publicly available for research.

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Author notes

The Genotype-Tissue Expression (GTEx) project was supported by the Common Fund of the Office of the Director of the National Institutes of Health (NIH), and by the National Cancer Institute (NCI); the National Human Genome Research Institute; the National Heart, Lung, and Blood Institute; the National Institute on Drug Abuse; the National Institute of Mental Health; and the National Institute of Neurological Disorders and Stroke. The work reported here was funded in whole or in part with federal funds from the NCI NIH under contract HHSN261200800001E.

The content here does not necessarily reflect the views or policies of the Department of Health and Human Services, nor does the mention of trade names, commercial products, or organizations imply endorsement by the United States government.

The authors have no relevant financial interest in the products or companies described in this article.

Supplementary data