A multivariate analysis of 59 candidate genes in personality traits: the temperament and character inventory (original) (raw)

Multivariate analysis of associations of 42 genes in ADHD, ODD and conduct disorder: Multivariate analysis of associations of 42 genes

Clinical Genetics, 2001

In a previous study (Comings DE et al. Comparison of the role of dopamine, serotonin, and noradrenergic genes in ADHD, ODD and conduct disorder. Multivariate regression analysis of 20 genes. Clin Genet 2000: 57: 178–196) we examined the role of 20 dopamine, serotonin and norepinephrine genes in attention deficit hyperactivity disorder (ADHD), oppositional defiant disorder (ODD), and conduct disorder (CD), using a multivariate analysis of associations (MAA) technique. We have now brought the total number of genes examined to 42 by adding an additional 22 candidate genes. These results indicate that even with the inclusion of these additional genes the noradrenergic genes still played a greater role in ADHD than any other group. Six other neurotransmitter genes were included in the regression equation – cholinergic, nicotinic, alpha 4 receptor (CHNRA4), adenosine A2A receptor (ADOA2A), nitric oxide synthase (NOS3), NMDAR1, GRIN2B, and GABRB3. In contrast to ADHD and ODD, CD preferentially utilized hormone and neuropeptide genes These included CCK, CYP19 (aromatase cytochrome P-450), ESR1, and INS (p=0.005). This is consistent with our prior studies indicating a role of the androgen receptor (AR) gene in a range of externalizing behavors. We propose that the MAA technique, by focusing on the additive effect of multiple genes and on the cummulative effect of functionally related groups of genes, provides a powerful approach to the dissection of the genetic basis of polygenic disorders.

Psychiatric genetics: the case of single gene disorders

European child & adolescent psychiatry, 2002

Quantitative and molecular genetics have made important developments in the last three decades. There is increasing evidence of the role of heredity in the field of neuropsychiatric disorders in children. So far, only a few pathways between genes and behaviour have been unravelled. Quantitative genetics puts polygenic inheritance models forward. Molecular genetic research based on these models seems promising, but until now has provided only a limited explanation for the variance in the studied neuropsychiatric disorders. In these models the complexity of the expression of a single gene grows exponentially with the number of genes involved. Consequently, research on the gene-phenotype relationships and phenotypical variability in such models is extremely complex.The candidate gene approach, in which the gene-phenotype pathway of a single gene is studied, is more manageable, and in our opinion essential in understanding multiple gene models. We discuss recent findings in the field an...

A ?line item? approach to the identification of genes involved in polygenic behavioral disorders: The Adrenergic ?2A(ADRA2A) gene

American Journal of Medical Genetics, 2003

The usual approach for using single base pair polymorphisms (SNPs) for the investigation of the genetics of behavioral disorders is to examine a single diagnostic syndrome or personality trait based on variables relating to a cluster of behavioral symptoms. However, since some of these variables may address behaviors that are associated with one allele while others are associated with the other allele, the overall association may be non-significant and significant sub-syndromal associations may be missed. Thus, we have reversed the process in a technique we term a “line item” approach. As a test of the technique we have examined the association between genotypes of a C- > G-1291 Msp I promotor SNP of the ADRA2A gene and 390 individual symptoms from a structured review of DSM-IV criteria for twelve different groups of symptoms. We examined 334 individuals consisting of controls and subjects with Tourette syndrome (TS). Based on the mean scores for each genotype, those symptoms that were individually significant at α ≤ 0.05 fell into three major groups by mode of inheritance: allele 1 codominant (11 > 12 > 22), allele 2 codominant (22 > 12 > 11), and negative heterosis (12 < 11, 22). Within each mode of inheritance group, the number of symptoms that were significant for the twelve symptom clusters was compared by chi-square analysis. This showed that symptoms were drawn from the diagnostic groups in a significantly non-random fashion. Thus, the allele 1 codominant symptoms came from the anxiety, affective, schizoid, and somatization diagnostic groups (internalizing symptoms) (χ2 = 80.0, d.f. = 11, P ≤ 0.0000001), while the allele 2 codominant symptoms came from the ADHD and oppositional defiant/conduct disorder diagnostic groups (externalizing symptoms) (χ2 = 81.0, d.f. = 11, P ≤ 0.0000001). The questions that fell in the negative heterosis type of inheritance were not significantly associated with specific diagnostic groups (P = 0.87). These results showed that the ADRA2A gene was associated with symptoms of autonomic, sympathetic dysfunction from different diagnostic groups. The advantages of the “line item” approach include (a) the identification of the symptoms associated with each allele, (b) the identification of symptom clusters independent of DSM diagnoses, (c) the elucidation of heterosis and other mode of inheritance effects, (d) the distinction between an association with a primary disorder versus a comorbid disorder, (e) the identification of associations with sub-syndromal symptom clusters that do meet full DSM-IV criteria, and (f) the identification of symptom clusters across databases. © 2003 Wiley-Liss, Inc.