Environmental vulnerability factors such as adverse childhood experiences in interaction with genetic risk variants, e.g., the serotonin transporter gene linked polymorphic region (5-HTTLPR), are assumed to play a role in the development of anxiety and affective disorders.
There is some evidence suggesting that a polymorphism of variable number of tandem repeats (VNTR) in the second intron of the serotonin transporter (5-HTT) gene and another variation which lies 1.2 kb upstream of the promoter of the gene (5-HTTLPR) are associated with affective disorders.
In particular, the presence of one or two copies of the short (s) allele of the 5-HTTLPR polymorphism has been associated with reduced serotonin transporter expression and function, and vulnerability to affective disorders.
Although the serotonin transporter length polymorphic region (5-HTTLPR) polymorphism is an extensively-investigated genetic marker of anxiety related personality traits (neuroticism and harm avoidance) and affective disorders, effect sizes in meta-analyses are small, if present at all, and all available primary studies to date lack mandatory statistical power.
Therefore, SERT knockout mice can be used as a tool to study 5-HTTLPR-related variations in personality and may be the etiology of affective disorders.
Further, 2 genetic polymorphisms: the 5-HTTLPR and the brain-derived neurotrophic factor (BDNF) Val66Met polymorphisms were not directly associated with familial risk for affective disorder and did not predict illness onset.
A deletion polymorphism in the serotonin transporter-linked polymorphic region (5-HTTLPR) has been associated with vulnerability to affective disorders, yet the mechanism by which this gene confers vulnerability remains unclear.
Negative affect such as depression and anxiety has been reported to be associated with morbidity and mortality, and polymorphisms of the serotonin transporter (5HTT) gene may be associated with such affect disorders.
Analysis did not show any statistically significant differences in the mean levels of anxiety, and mood disorders in women in relation to genotypes of the 5-HTTLPR (SLC6A4) polymorphism and the 30-bp VNTR polymorphism in the MAO A promoter region.
There is evidence for an association between two different polymorphisms of the human serotonin transporter gene (5-HTT) and the personality trait of neuroticism and affective disorder.
A functional polymorphism within the serotonin transporter gene (5-HTTLPR) has been reported to modulate emotionality and risk for affective disorders.
The alleged association between the serotonin-transporter-linked polymorphic region (5-HTTLPR) and amygdala activation forms a cornerstone of the common view that carrying the short allele of this polymorphism is a potential risk factor for affective disorders.
an association was found between 5-HTTLPR polymorphism and scores on three MMPI scales: Psychopathic deviance, Paranoia and Schizophrenia in patients with affective disorders and S chizophrenia in normal subjects.
Two hundred and thirty inpatients affected by mood disorders (160 bipolar and 70 major depressive disorder) were assessed by the Operational Criteria checklist for psychotic illness (OPCRIT) and were also typed for the 5-HTTLPR variants using PCR techniques.
Positive associations of the 5-HTTLPR polymorphism with mood disorders, anxiety-related personality traits, autism and late-onset Alzheimer's disease have been published, although some non replications were also reported.
A functional polymorphism (a 44-base pair insertion (L)/deletion (S)) in the promoter of the gene encoding the serotonin transporter (5-HTTLPR), associated with mood disorders, has been inconsistently associated with suicidality.
The serotonin transporter gene promoter polymorphism (5-HTTLPR) has been repeatedly associated with antidepressant response in mood disorder patients, but findings are not consistent across studies.
Considering the allele-specific sensitivity of SLC6A4 methylation to SLEs, this study may help clarify the role of SLC6A4 in the development of affective disorders.
In the present study, we evaluated the impact of the BDNF Val66Met polymorphism on individual differences in personality traits in a sample of healthy volunteers in relation to other common gene variants thought to be involved in the pathophysiology of affective disorders, such as the serotonin transporter promoter polymorphism (5-HTTLPR) and a variable number of tandem repeat polymorphism of the dopamine transporter gene (DAT VNTR).