# Heritability of Gene Expression Measured from Peripheral Blood in Older Adults

## TL;DR

This study finds that about 24% of genes in older adults have heritable expression in blood, with immune and aging-related genes being especially notable.

## Contribution

The study provides new insights into gene expression heritability in older adults, a demographic underrepresented in prior research.

## Key findings

- 5269 probes from 4603 genes showed significant heritability in older adults.
- Top heritable genes were enriched for immune response and aging-related pathways.
- Only 38 genes overlapped significantly across studies of different adult age groups.

## Abstract

The contributions of genetic variation and the environment to gene expression may change across the lifespan. However, few studies have investigated the heritability of blood gene expression in older adults. The current study therefore aimed to investigate this question in a community sample of older adults. A total of 246 adults (71 MZ and 52 DZ twins, 69.91% females; mean age—75.79 ± 5.44) were studied. Peripheral blood gene expression was assessed using Illumina microarrays. A heritability analysis was performed using structural equation modelling. There were 5269 probes (19.9%) from 4603 unique genes (23.9%) (total 26,537 probes from 19,256 genes) that were significantly heritable (mean h2 = 0.40). A pathway analysis of the top 10% of significant genes showed enrichment for the immune response and ageing-associated genes. In a comparison with two other gene expression twin heritability studies using adults from across the lifespan, there were 38 out of 9479 overlapping genes that were significantly heritable. In conclusion, our study found ~24% of the available genes for analysis were heritable in older adults, with only a small number common across studies that used samples from across adulthood, indicating the importance of examining gene expression in older age groups.