NEW YORK (GenomeWeb) – A genome-wide analysis has uncovered genetic links between empathy and certain psychiatric conditions and psychological traits.
Empathy, which helps cultivate relationships among people, includes both the ability to recognize someone else's thoughts and feelings as well as the ability to respond with appropriate reciprocal emotions. While empathy is shaped by early experiences, parenting, and other social factors, it's also thought to have a biological basis and is affected in conditions like autism and schizophrenia.
The University of Cambridge's Simon Baron-Cohen and his colleagues conducted a genome-wide association study of empathy using nearly 47,000 research participants from 23andMe. While the researchers reported in Translational Psychiatry yesterday that they were unable to home in on any significant loci, they did find 11 loci with suggestive connections to empathy and estimated that about a tenth of variation in empathy is due to genetic factors. Additionally, the researchers did uncover genetic correlations between empathy and autism, and between empathy and schizophrenia.
"Finding that even a fraction of why we differ in empathy is due to genetic factors helps us understand people such as those with autism who struggle to imagine another person's thoughts and feelings," Baron-Cohen, one of three joint senior authors on the paper, said in a statement.
For their study, Baron-Cohen and his colleagues drew upon 46,861 23andMe customers who consented to take part in research. Ninety-seven percent of the cohort was of European descent, and about half were male and half female.
These individuals were genotyped using one of four Illumina approaches, had their data imputed to 1000 Genomes Project data, and, after quality control, had more than 9.9 million SNPs analyzed. The participants also completed an Empathy Quotient (EQ) questionnaire, a widely used measure of cognitive and affective empathy.
Since women tend to perform better on measures of empathy — which the researchers found here as well — they conducted three GWAS analyses: a male-only analysis, a female-only analysis, and a combined analysis.
While the researchers were unable to tease out any SNPs that reached genome-wide significance, they noted 11 loci with suggestive links to empathy, including one within an intron of TMEM132C. A gene-based analysis further pointed to two genes significant for EQ: SEMA6D and FBN2.
Based on the SNPs they analyzed, the researchers used a Linkage Disequilibrium Score Regression (LDSR) analysis to determine the heritability of EQ, estimating it to be 0.11. When they again divided their population by sex, they noted no difference in heritability between men and women. They also reported high genetic correlation between the sexes. This suggested to the researchers that differences in empathy between men and women could instead be due to non-genetic biological differences such as hormones, or to social factors such as differences in socialization.
The researchers also explored genetic connections between empathy and six psychiatric conditions — including autism, anorexia nervosa, and schizophrenia — six psychological traits — including extraversion, openness to experience, and neuroticism — and educational attainment.Again, taking an LDSR approach, they found links between EQ and autism, schizophrenia, anorexia nervosa, and extroversion. They noted that the correlation between EQ and autism was inverse, as would be expected from previous studies that have found that people with autism have trouble recognizing the mental states of others.
Though the researchers noted that their study is the largest GWAS of empathy, it has a number of limitations, including modest statistical power and a reliance on self reports.
"This new study demonstrates a role for genes in empathy, but we have not yet identified the specific genes that are involved," joint senior author Thomas Bourgeron from Institut Pasteur said in a statement. "Our next step is to gather larger samples to replicate these findings, and to pin-point the precise biological pathways associated with individual differences in empathy."