A recent study published in Molecular psychiatry successfully identified 11 independent genetic loci associated with delay discounting (DD).
First, it examined how these variants influence physical, behavioral, and neuroimaging characteristics associated with both physical and psychiatric health outcomes.
What is DD?
DD is primarily inclined to prefer immediate, smaller rewards over delayed but substantial rewards. It is an inherited trait linked to several disorders signaled by reduced impulsivity and decision-making.
On the contrary, obsessive-compulsive disorder is associated with lower DD.
How was the research conducted?
The researchers measured DD using the intertemporal choice. This curve is steeper when instant gratification is preferred, compared to a flat trajectory.
A previous genome-wide association study (GWAS) provided genetic data for 134,935 participants of the 23andMe cohort, all of European descent.
The study analyzed both global and genetic links between DD and health outcomes; network analyzes were used to scrutinize the different molecular pathways involved in these processes.
Meanwhile, multidimensional analyzes were used to analyze genetic factors unique to DD, compared to those shared with other intellectual qualities such as educational level, intelligence and executive functions.
Study results revealed 93 unique DD-associated genes
The GWAS analysis revealed eleven significant loci containing 93 unique DD-associated genes, 20% of which were within the ch16p11.2 GWAS locus.
The recent analysis differs from previously reported association with the chromosomal locus rs6528024 (chrXq13.3).
The results showed that the observed genetic variants were single-nucleotide polymorphisms (SNPs) that explained 9.9% of the differences in DD between individuals.
It was observed that most SNPs were present in places previously associated with entrepreneurship, substance abuse and psychiatric disorders.
DD is mainly associated with 73 psychiatric, physical and cognitive characteristics. A subset of these correlations remained notable due to shared genetic influences with cognitive traits including education, intelligence, and executive function.
Metabolic pathways shared between DD and BMI also overlap with those associated with schizophrenia, externalizing behavior, and educational attainment.
Study conclusions and pave the way for future revelations
The current study used a fivefold sample than the work done by previous employees. However, eleven genetic loci, including 93 genes, were found to be closely associated with the risk of DD.
The study underlines a higher predisposition to DD that reflects shared biological pathways that overlap with cognitive operations, psychiatric conditions such as depression and metabolic health consequences.
Nevertheless, future work will contribute to extending the PheWAS performance to a non-European cohort, as the PGS developed on European data becomes inaccurate in populations with different ancestry.
