A 44 base pair insertion ("l")/deletion ("s") polymorphism (called 5-HTTLPR) in the 5' promoter region of the human serotonin transporter gene (SLC6A4) modulates expression and has been associated to anxiety and depressive traits in otherwise healthy individuals. In individuals with psychiatric diagnoses, including schizophrenia, it seems to modulate symptom severity. Thus, it may be a disease modifying gene.
The major psychotic disorders schizophrenia and bipolar disorder are etiologically complex involving both heritable and nonheritable factors. The absence of consistently replicated major genetic effects, together with evidence for lasting changes in gene expression after environmental exposures, is consistent with the concept that the biologic underpinnings of these disorders are epigenetic in form rather than DNA sequence based.
Epigenetic mechanisms may moderate genetic and environmental risk (GxE) for mood disorders. We used an experimental rhesus macaque model of early life stress to test whether epigenetic regulation of serotonin transporter (5-HTT) may contribute to GxE interactions that influence behavior and emotion.
BACKGROUND: Do genetic or epigenetic factors play a role in making some individuals more vulnerable than others to loss of attachment figures or other traumatic experiences? METHODS: DNA was obtained from growth phase entrained Epstein-Barr Virus (EBV) transformed lymphoblast cell lines from 143 adopted participants. Genotype of the serotonin transporter linked polymorphic region (5HTTLPR) was determined, and methylation ratios for each of the C-phosphate-G (CpG) residues were assessed using quantitative mass spectroscopy.
Progress in Neuro-Psychopharmacology & Biological Psychiatry
Several diseases are known to have a multifactorial origin, depending not only on genetic but also on environmental factors. They are called "complex disorders" and include cardiovascular disease, cancer, diabetes, and neuropsychiatric and neurodegenerative diseases. In the latter class, Alzheimer's (AD) and Parkinson's diseases (PD) are by far the most common in the elderly and constitute a tremendous social and economical problem.
BACKGROUND: Research suggests that the COMT Val(158)Met, BDNF Val(66)Met and OPRM1 A(118)G polymorphisms moderate the experience of pain. In order to obtain experimental confirmation and extension of findings, cortical processing of experimentally-induced pain was used. METHOD: A sample of 78 individuals with chronic low back pain complaints and 37 healthy controls underwent EEG registration. Event-Related Potentials were measured in response to electrical nociceptive stimuli and moderation by COMT Val(158)Met, BDNF Val(66)Met and OPRM1 A(118)G polymorphisms was assessed.
Kindling and behavioural sensitization were probably the first among the animal models of affective disorders, to suggest that genes-environment interactions were likely to be involved in the pathophysiology of these disorders. Cross-sensitization among stressors, drugs of abuse and illness episodes was deemed to be supported by the induction of a series of transcription factors, such as the proto-oncogene c-fos that subsequently alter gene expression by binding at DNA sites and inducing mRNAs for substances that may exert effects over long time periods.
We have recently shown that the expression of spermidine/spermine N1-acetyltransferase (SAT1) is downregulated across the brains of suicide completers, and that its expression is influenced by genetic variations in the promoter. Several promoter polymorphisms in SAT1, including rs6526342, have been associated with suicide and other psychiatric disorders, and display haplotype-specific effects on expression. However, these effects cannot explain total variability in SAT1 expression, and other regulatory mechanisms, such as epigenetic factors, may also be at play.
INTRODUCTION: HTR2A gene has been the subject of numerous studies in psychiatric genetics because LSD, which resembles serotonin causes psychosis and atypical antipsychotic drugs target the HTR2A receptor. However, evidence for the role of HTR2A polymorphism(s) in schizophrenia (SCZ) and bipolar disorder (BD) has been elusive. We hypothesized that epigenetic dysregulation of HTR2A may be involved in psycho-pathogenesis and analyzed promoter DNA methylome and expression of HTR2A in SCZ, BD and control subjects.
A principal weakness of evidence-based psychiatry is that it does not account for the individual variability in therapeutic response among individuals with the same diagnosis. The aim of personalized psychiatry is to remediate this shortcoming and to use predictors to select treatment that is most likely to be beneficial for an individual. This article reviews the evidence that genetic variation, environmental exposures, and gene-environment interactions shape mental illness and influence treatment outcomes, with a primary focus on depression.