Genetic repositories for the study of major psychiatric conditions: what do we know about ethnic minorities' genetic vulnerability?

Genetic moderation of the effects of the Family Check-Up intervention on children's internalizing symptoms: A longitudinal study with a racially/ethnically diverse sample

Development involves synergistic interplay among genotypes and the physical and cultural environments, and integrating genetics into experimental designs that manipulate the environment can improve understanding of developmental psychopathology and intervention efficacy. Consistent with differential susceptibility theory, individuals can vary in their sensitivity to environmental conditions including intervention for reasons including their genotype. As a consequence, understanding genetic influences on intervention response is critical. Empirically, we tested an interaction between a genetic index representing sensitivity to the environment and the Family Check-Up intervention. Participants were drawn from the Early Steps Multisite randomized prevention trial that included a low-income and racially/ethnically diverse sample of children and their families followed longitudinally (n = 515). As hypothesized, polygenic sensitivity to the environment moderated the effects of the intervention on 10-year-old children's symptoms of internalizing psychopathology, such that children who were genetically sensitive and were randomly assigned to the intervention had fewer symptoms of child psychopathology than genetically sensitive children assigned to the control condition. A significant difference in internalizing symptoms assessed with a clinical interview emerged between the intervention and control groups for those 0.493 SD above the mean on polygenic sensitivity, or 25% of the sample. Similar to personalized medicine, it is time to understand individual and sociocultural differences in treatment response and individualize psychosocial interventions to reduce the burden of child psychopathology and maximize well-being for children growing up in a wide range of physical environments and cultures.

Examining interactions between genetic risk for alcohol problems, peer deviance, and interpersonal traumatic events on trajectories of alcohol use disorder symptoms among African American college students

Numerous studies have demonstrated that genetic and environmental factors interact to influence alcohol problems. Yet prior research has primarily focused on samples of European descent and little is known about gene–environment interactions in relation to alcohol problems in non-European populations. In this study, we examined whether and how genetic risk for alcohol problems and peer deviance and interpersonal traumatic events independently and interactively influence trajectories of alcohol use disorder symptoms in a sample of African American students across the college years (N = 1,119; Mage= 18.44 years). Data were drawn from the Spit for Science study where participants completed multiple online surveys throughout college and provided a saliva sample for genotyping. Multilevel growth curve analyses indicated that alcohol dependence genome-wide polygenic risk scores did not predict trajectory of alcohol use disorder symptoms, while family history of alcohol problems was associated with alcohol use disorder symptoms at the start of college but not with the rate of change in symptoms over time. Peer deviance and interpersonal traumatic events were associated with more alcohol use disorder symptoms across college years. Neither alcohol dependence genome-wide polygenic risk scores nor family history of alcohol problems moderated the effects of these environmental risk factors on alcohol use disorder symptoms. Our findings indicated that peer deviance and experience of interpersonal traumatic events are salient risk factors that elevate risk for alcohol problems among African American college students. Family history of alcohol problems could be a useful indicator of genetic risk for alcohol problems. Gene identification efforts with much larger samples of African descent are needed to better characterize genetic risk for alcohol use disorders, in order to better understand gene–environment interaction processes in this understudied population.

Polygenic risk, family cohesion, and adolescent aggression in Mexican American and European American families: Developmental pathways to alcohol use

Poor family cohesion and elevated adolescent aggression are associated with greater alcohol use in adolescence and early adulthood. In addition, evocative gene-environment correlations (rGEs) can underlie the interplay between offspring characteristics and negative family functioning, contributing to substance use. Gene-environment interplay has rarely been examined in racial/ethnic minority populations. The current study examined adolescents' polygenic risk scores for aggression in evocative rGEs underlying aggression and family cohesion during adolescence, their contributions to alcohol use in early adulthood (n = 479), and differences between Mexican American and European American subsamples. Results suggest an evocative rGE between polygenic risk scores, aggression, and low family cohesion, with aggression contributing to low family cohesion over time. Greater family cohesion was associated with lower levels of alcohol use in early adulthood and this association was stronger for Mexican American adolescents compared to European American adolescents. Results are discussed with respect to integration of culture and racial/ethnic minority samples into genetic research and implications for alcohol use.

Identification of circadian gene variants in bipolar disorder in Latino populations

BACKGROUND

Variations in circadian genes can impact biological rhythms. Given the rhythm disturbances that characterize bipolar disorder (BD), genes encoding components of molecular clocks are good candidate genes for the illness.

METHODS

A family based association analysis of circadian gene single nucleotide polymorphisms (SNPs) and BD was conducted in Latino pedigrees. 884 individuals from 207 pedigrees (473BP phenotype and 411 unaffected family members) were genotyped. Family based single marker association testing was performed. Ancestral haplotypes (SNPs found to be in strong LD defined using confidence intervals) were also tested for association with BD.

RESULTS

Multiple suggestive associations between circadian gene SNPs and BD were noted. These included CSNK1E (rs1534891, p=0.00689), ARNTL (rs3789327, p=0.021172), CSNK1D (rs4510078, p=0.022801), CLOCK (rs17777927, p=0.031664). Individually, none of the SNPs were significantly associated with BD after correction for multiple testing. However, a 4-locus CSNK1E haplotype encompassing the rs1534891 SNP (Z-score=2.685, permuted p=0.0076) and a 3-locus haplotype in ARNTL (Z-score=3.269, permuted p=0.0011) showed a significant association with BD.

LIMITATIONS

Larger samples are required to confirm these findings and assess the relationship between circadian gene SNPs and BD in Latinos.

CONCLUSIONS

The results suggest that ARNTL and CSKN1E variants may be associated with BD. Further studies are warranted to assess the relationships between these genes and BD in Latino populations.

A roadmap for the integration of culture into developmental psychopathology

In this paper, I propose a roadmap for the integration of culture in developmental psychopathology. This integration is pressing because culture continues to be somewhat disconnected from theory, research, training, and interventions in developmental psychopathology, thus limiting our understanding of the epigenesis of mental health. I argue that in order to successfully integrate culture into developmental psychopathology, it is crucial to (a) study cultural development, (b) consider both individual-level and social-level cultural processes, (c) examine the interplay between culture and biology, and (d) promote improved and direct cultural assessment. I provide evidence in support of each of these guidelines, present alternative conceptual frameworks, and suggest new lines of research. Hopefully, that these directions will contribute to the emerging field of cultural development and psychopathology, which focuses on the elucidation of the cultural processes that initiate, maintain, or derail trajectories of normal and abnormal behavior.

Common genetic influences on depression, alcohol, and substance use disorders in Mexican-American families

Multiple genetic and environmental factors influence the risk for both major depression and alcohol/substance use disorders. In addition, there is evidence that these illnesses share genetic factors. Although, the heritability of these illnesses is well established, relatively few studies have focused on ethnic minority populations. Here, we document the prevalence, heritability, and genetic correlations between major depression and alcohol and drug disorders in a large, community-ascertained sample of Mexican-American families. A total of 1,122 Mexican-American individuals from 71 extended pedigrees participated in the study. All subjects received in-person psychiatric interviews. Heritability, genetic, and environmental correlations were estimated using SOLAR. Thirty-five percent of the sample met criteria for DSM-IV lifetime major depression, 34% met lifetime criteria for alcohol use disorders, and 8% met criteria for lifetime drug use disorders. The heritability for major depression was estimated to be h(2) = 0.393 (P = 3.7 × 10(-6)). Heritability estimates were higher for recurrent depression (h(2) = 0.463, P = 4.0 × 10(-6)) and early onset depression (h(2) = 0.485, P = 8.5 × 10(-5)). While the genetic correlation between major depression and alcohol use disorders was significant (ρ(g) = 0.58, P = 7 × 10(-3)), the environmental correlation between these traits was not significant. Although, there is evidence for increased rates of depression and substance use in US-born individuals of Mexican ancestry, our findings indicate that genetic control over major depression and alcohol/substance use disorders in the Mexican-American population is similar to that reported in other populations.

The effects of child maltreatment and polymorphisms of the serotonin transporter and dopamine D4 receptor genes on infant attachment and intervention efficacy

This investigation examined the extent to which polymorphisms of the serotonin transporter linked promoter region (5-HTTLPR) and the dopamine receptor D4 (DRD4) genes differentially influenced the development of attachment security and disorganization in maltreated and nonmaltreated infants at age 13 months, and the extent to which the efficacy of preventive interventions to promote attachment security were influenced by genetic variation. The sample consisted of 106 infants from maltreating families, participating in a randomized control trial evaluating the efficacy of two interventions, child–parent psychotherapy and psychoeducational parenting intervention, and 47 infants from nonmaltreating families. DNA samples were genotyped for polymorphisms of5-HTTLPR,DRD4exon III variable number tandem repeat, andDRD4-521. Attachment organization at age 1 and at age 2 was assessed with the Strange Situation for all participants, prior to and following the completion of the interventions. High rates of disorganized attachment were observed in the maltreatment compared to the nonmaltreatment group, and both interventions resulted in increased rates of attachment security at age 2. Genetic variation did not influence improvement in attachment organization among maltreated infants. Among maltreated infants, genetic variation had minimal effect on attachment organization. In contrast, among nonmaltreated infants,5-HTTLPRandDRD4polymorphisms influenced attachment security and disorganization at age 2 and the stability of attachment disorganization over time.

Application of systems biology approach identifies and validates GRB2 as a risk gene for schizophrenia in the Irish Case Control Study of Schizophrenia (ICCSS) sample

Recently, we prioritized 160 schizophrenia candidate genes (SZGenes) by integrating multiple lines of evidence and subsequently identified twenty-four pathways in which these 160 genes are overrepresented. Among them, four neurotransmitter-related pathways were top ranked. In this study, we extended our previous pathway analysis by applying a systems biology approach to identifying candidate genes for schizophrenia. We constructed protein-protein interaction subnetworks for four neurotransmitter-related pathways and merged them to obtain a general neurotransmitter network, from which five candidate genes stood out. We tested the association of four genes (GRB2, HSPA5, YWHAG, and YWHAZ) in the Irish Case-Control Study of Schizophrenia (ICCSS) sample (1021 cases and 626 controls). Interestingly, six of the seven tested SNPs in GRB2 showed significant signal, two of which (rs7207618 and rs9912608) remained significant after permutation test or Bonferroni correction, suggesting that GRB2 might be a risk gene for schizophrenia in Irish population. To our knowledge, this is the first report of GRB2 being significantly associated with schizophrenia in a specific population. Our results suggest that the systems biology approach is promising for identification of candidate genes and understanding the etiology of complex diseases.