Genetic Association of the PERIOD3 (Per3) Clock Gene with Bipolar Disorder.

Objective: Circadian rhythms have been linked to psychiatric disorders such as Depression and Bipolar Disorder (BD). Given previous evidences of sleep/circadian disturbances as well as the genetic susceptibility for BD, we decided to investigate the possible link between the PERIOD3 (Per3) circadian gene and BD.

Methods: This is a genetic association case (BD) vs.

Association between the Catechol O-methyltransferase (COMT) Val158met polymorphism and different dimensions of impulsivity.

Background: Impulsivity is a multidimensional construct which has been associated with dopaminergic neurotransmission. Nonetheless, until this moment, few studies addressed the relationship between different types of impulsivity and the single nucleotide polymorphism caused by a substitution of valine (val) with methionine (met) in the 158 codon of the Catechol-o-Methyltransferase gene (COMT-val158met). The present study aimed to investigate the association between val158met COMT polymorphism and impulsive behavior measured by two neuropsychological tests.

Association between tryptophan hydroxylase-2 gene and late-onset depression.

Objective: The aim of this study was to examine the association between polymorphisms (SNP) in the tryptophan hydroxylase-2 (TPH2) gene and late-onset depression (LOD) in the Brazilian population.

Methods: We genotyped 8 tag SNPs in the TPH2 gene in 84 outpatients with LOD and 79 individuals belonging to the comparison group to investigate an association between the TPH2 gene and LOD.

Results: Our findings suggested an association between tag SNP rs4565946 heterozygous C/T (p = 0.

The role of BDNF genetic polymorphisms in bipolar disorder with psychiatric comorbidities.

Background: Bipolar disorder (BD) is a complex disorder where genetic factors play a major role in its etiology. Probably, no other axis I diagnosis has a co-morbidity prevalence as high as BD. Since BDNF is involved in different ways in various psychiatric disorders we hypothesized that its genetic polymorphisms could be associated with the co-morbidity phenomenon in BD.

Association study of tryptophan hydroxylase 2 gene polymorphisms in bipolar disorder patients with panic disorder comorbidity.

Frequent comorbidity between panic disorder (PD) and mood disorders has been widely reported in clinical and epidemiological studies and, recently, an increasing attention has been paid to the cooccurrence of PD and bipolar disorder (BD). Several studies have shown that an imbalance of serotonin activity could be related to panic symptoms. Tryptophan hydroxylase 2 (TPH2) are plausible candidates for the association with PD.