Psychopathic traits mediate the association of serotonin transporter genotype and child externalizing behavior

Associations of the MAOA uVNTR genotype and 5-HTTLPR/rs25531 haplotype with psychopathic traits

Previous studies have linked polymorphisms of the monoamine oxidase A (MAOA uVNTR) and serotonin transporter gene (5-HTTLPR) to individual differences in the expression of psychopathic traits, but findings remain inconsistent. One possible reason is that these studies have treated psychopathy as a unitary construct when there is accumulating evidence that there are variants or subtypes. We used a variable-centered and a person-centered approach by (a) examining putative genetic correlates of psychopathy across individuals and (b) comparing the frequencies of the MAOA uVNTR genotype and 5-HTTLPR/rs25531 haplotype between empirically derived subtypes of psychopathy, respectively. Notably, we included the often neglected rs25531 polymorphism, which is closely connected to the 5-HTTLPR. Based on data from male offenders and community volunteers, structural equation modeling indicated that the 5-HTTLPR/rs25531 haplotype was specifically associated with interpersonal deficits beyond the overarching psychopathy construct. Latent profile analysis revealed four clusters that were labeled non-psychopaths, sociopaths, callous-conning, and psychopaths. The low-activity variant of the 5-HTTLPR/rs25531 haplotype was significantly more frequent in the callous-conning compared to the non-psychopathic subtype. There were no effects for the MAOA uVNTR. The results illustrate that psychopathy should not be treated as a unitary construct but that there are variants with specific profiles of psychopathic traits, and that the 5-HTTLPR/rs25531 haplotype plays a role in the manifestation of interpersonal deficits from a variable-centered as well as from a person-centered view.

The genetic underpinnings of callous-unemotional traits: A systematic research review

BACKGROUND

Callous-unemotional (CU) traits represent the affective features of psychopathy used to delineate youth at high risk for externalizing pathology. The genetic etiology CU traits is not currently well-understood.

METHODS

The current review surveyed the literature for studies on the genetic underpinnings of CU traits and integrated information from 39 genetic studies.

RESULTS

The results from 24 studies with quantitative data suggest that the heritability for CU traits is likely between 36-67%. A majority of the 16 molecular genetic studies focused on candidate genes in the serotonin and oxytocin systems with results that have not been well replicated. Although two genome-wide association studies have been conducted, no genome-wide significant loci have been discovered.

DISCUSSION

There is some evidence to suggest that the serotonin and oxytocin systems may play a role in CU traits; however, there is currently not enough evidence to implicate specific genetic mechanisms. The authors encourage researchers to continue to apply the most up-to-date and relevant methodology, specifically collaborations and consortiums using genome-wide and polygenic methods.

Sometimes It's Good to be Short: The Serotonin Transporter Gene, Positive Parenting, and Adolescent Depression

In threatening environments, the short (S) allele of 5-HTTLPR is proposed to augment risk for depression. However, it is unknown whether 5-HTTLPR variation increases risk for depression in environments of deprivation, lacking positive or nurturant features. Two independent longitudinal studies (n = 681 and 176, respectively) examined whether 5-HTTLPR moderated associations between low levels of positive parenting at 11-13 years and subsequent depression at 17-19 years. In both studies only LL homozygous adolescents were at greater risk for depression with decreasing levels of positive parenting. Thus, while the S allele has previously been identified as a susceptible genotype, these findings suggest that the L allele may also confer sensitivity to depression in the face of specific environmental challenges.