Suicide behavior as a quantitative trait and its genetic background

INTRODUCTION

Studies have not given yet a clear answer what is the genetic background of suicidal predisposition. The associations between polymorphisms of the TPH1 and 5-HTTLPR genes and violent suicidal behavior was revealed with the least inconsistencies.

METHOD

We selected 10 "strong candidate genes" and 35 SNPs, SLC6A4 and ACP1 for replication study. We searched associations between precisely described suicidal phenotype in 825 affective patients and polymorphisms of selected neurobiological pathways genes as well as their interactions that constitute suicidal risk.

RESULTS

The results confirm the role of TPH1, TPH2, 5HT2A, CRHR1 and ACP1 variants in the risk of suicidal behavior.

LIMITATIONS

In our study we analyzed limited number of candidate genes and only one of them is linked to lithium mechanism of action. We had no data on pharmacological treatment of investigated patients and its relation to the time of suicide attempt.

CONCLUSION

Our results indicate that polymorphisms of various signaling pathways are involved in the pathogenesis of suicidal behavior. Non-genetic factors are also involved in the risk of suicidal attempts.

A Lack of Correlation between Brain-Derived Neurotrophic Factor Serum Level and Verbal Memory Performance in Healthy Polish Population

Brain derived neurotrophic factor (BDNF) is considered to be connected with memory and learning through the processes of long term synaptic potentiation and synaptic plasticity. The aim of the study was to examine the relationship between precursor BDNF (proBNDF) and mature BDNF (mBDNF) serum levels and performance on Rey Auditory-Verbal Learning Test (RAVLT) in 150 healthy volunteers. In addition, we have verified the relationships between serum concentration of both forms of BDNF and RAVLT with sociodemographic and lifestyle factors.We found no strong evidence for the correlation of proBDNF and mBDNF serum levels with performance on RAVLT in healthy Polish population in early and middle adulthood. We observed the mBDNF serum concentration to be higher in women compared with men. Moreover, we revealed higher mBDNF level to be connected with lower body mass index (BMI). In turn, the results of RAVLT correlated with sociodemographic and lifestyle factors, such as: age, education, gender, BMI and smoking.

Association study of functional polymorphisms in interleukins and interleukin receptors genes: IL1A, IL1B, IL1RN, IL6, IL6R, IL10, IL10RA and TGFB1 in schizophrenia in Polish population

Schizophrenia has been associated with a large range of autoimmune diseases, with a history of any autoimmune disease being associated with a 45% increase in risk for the illness. The inflammatory system may trigger or modulate the course of schizophrenia through complex mechanisms influencing neurodevelopment, neuroplasticity and neurotransmission. In particular, increases or imbalance in cytokine before birth or during the early stages of life may affect neurodevelopment and produce vulnerability to the disease. A total of 27 polymorphisms of IL1N gene: rs1800587, rs17561; IL1B gene: rs1143634, rs1143643, rs16944, rs4848306, rs1143623, rs1143633, rs1143627; IL1RN gene: rs419598, rs315952, rs9005, rs4251961; IL6 gene: rs1800795, rs1800797; IL6R gene: rs4537545, rs4845617, rs2228145, IL10 gene: rs1800896, rs1800871, rs1800872, rs1800890, rs6676671; IL10RA gene: rs2229113, rs3135932; TGF1B gene: rs1800469, rs1800470; each selected on the basis of molecular evidence for functionality, were investigated in this study. Analysis was performed on a group of 621 patients with diagnosis of schizophrenia and 531 healthy controls in Polish population. An association of rs4848306 in IL1B gene, rs4251961 in IL1RN gene, rs2228145 and rs4537545 in IL6R with schizophrenia have been observed. rs6676671 in IL10 was associated with early age of onset. Strong linkage disequilibrium was observed between analyzed polymorphisms in each gene, except of IL10RA. We observed that haplotypes composed of rs4537545 and rs2228145 in IL6R gene were associated with schizophrenia. Analyses with family history of schizophrenia, other psychiatric disorders and alcohol abuse/dependence did not show any positive findings. Further studies on larger groups along with correlation with circulating protein levels are needed.

FKBP5 polymorphism is associated with major depression but not with bipolar disorder

BACKGROUND

Altered activity of hypothalamus-pituitary-adrenal glands (HPA) axis in response to stress underlies the pathogenesis of mood disorders such as depression and bipolar disorder. Chaperone proteins regulate sensitivity of glucocorticoid receptor (GR) to steroids. We hypothesized that genetic variants within the FKBP5 - gene encoding co-chaperone protein essential in GR signaling - may influence the susceptibility to major depressive disorder and bipolar disorder.

METHODS

In the study participated 528 bipolar patients, 218 patients with major depressive disorder and 742 subjects from control group. Genotypes for eight FKBP5 polymorphisms (rs1360780, rs755658, rs9470080, rs4713916, rs7748266, rs9296158, rs9394309, rs3800373) were established by TagMan SNP Genotyping Assays (Applied Biosystems). Linkage disequilibrium analysis for FKBP5 gene was done in Haploview. Gene-gene interactions between FKBP5 and NR3C1 polymorphisms (reported previously) were analyzed using the multidimensionality-reduction method (MDR).

RESULTS

We have observed an association between five FKBP5 polymorphisms (rs1360780, rs9470080, rs4713916, rs9296158 and rs9394309) and major depressive disorder (p=0.011; p=0.007, p=0.038; p=0.030; p=0.018, respectively), but not bipolar disorder. In linkage disequilibrium analysis we found that seven FKBP5 polymorphisms build haplotype block (rs3800373, rs755658, rs9296158, rs7748266, rs1360780, rs9394309, rs9470080, respectively). We observed that two haplotype combinations (ACATTGT and CCACTAT) were significantly more frequent in the MDD patients than in controls (p=0.014 and p=0.043). We have not observed such an association for BD patients. We have found that interaction between rs9470080 of FKBP5 and rs6198 of NR3C1 influences MDD risk.

LIMITATIONS

The main limitations of this study include low power and limited sample size of MDD patients.

CONCLUSIONS

Single markers and haplotypes of FKBP5 gene and the interaction with glucocorticoid receptor gene (NR3C1) may influence MDD predisposition.

Glucocorticoid receptor polymorphism is associated with major depression and predominance of depression in the course of bipolar disorder

BACKGROUND

A strong association has been found between dysregulation of hypothalamic-pituitary-adrenal (HPA) axis and depression and bipolar disorder. Glucocorticoid receptor is one of the involved receptors and its gene has been recognized as a candidate gene for major depressive disorder and bipolar disorder. Therefore, we investigated if polymorphism of the glucocorticoid receptor gene (NR3C1), involved in the regulation of HPA axis, may alter susceptibility as well as the course of major depressive disorder and bipolar disorder.

METHODS

In the study we included 514 patients with bipolar disorder and 193 patients with major depressive disorder. Consensus diagnosis by at least two psychiatrists was made, according to DSM-IV (Diagnostic and Statistical Manual of Mental Disorders) criteria, using SCID (Structured Clinical Interview for DSM Disorders). Control group consisted of 732 healthy subjects. Genotyping for eight NR3C1 polymorphisms was done with use of TaqMan SNP (single nucleotide polymorphism) Genotyping Assays. Linkage disequilibrium analysis was done in Haploview.

RESULTS

We have found three polymorphisms (rs6198, rs6191 and rs33388) to be associated with major depressive disorder (MDD) and the same polymorphisms were associated with the predominance of depressive symptoms in the course of bipolar disorder. In linkage disequilibrium analysis we observed two haplotype blocks, however, none of those shows involvement in susceptibility to MDD or bipolar disorder.

LIMITATIONS

The main limitation of this study is relatively small sample size of MDD patients group.

CONCLUSIONS

Polymorphisms of NR3C1 gene analyzed in this study may modify susceptibility to major depressive disorder and seem to influence the course of bipolar disorder.

FYN kinase gene: another glutamatergic gene associated with bipolar disorder?

Several genes of the glutamatergic system have been implicated in both schizophrenia and bipolar disorder. The Src family tyrosine kinase FYN plays a key role in the interaction between brain-derived neurotrophic factor and glutamatergic receptor N-methyl-D-aspartate. Although no association between FYN gene polymorphisms and schizophrenia has been demonstrated, in our previous paper we found an association between FYN polymorphisms and cognitive test performance in schizophrenic patients. The aim of this study was to find a possible association of three polymorphisms of the FYN gene with bipolar disorder. We analyzed 425 bipolar patients and 518 control subjects. Genotypes of three analyzed polymorphisms, i.e. rs706895 (-93A/G in the 5'-flanking region), rs6916861 (Ex12+894T/G in the 3'-UTR) and rs3730353 (IVS10+37T/C in intron 10) were established by PCR-RFLP. A significant association was found between rs6916861 T/G and rs3730353 T/C polymorphisms of the FYN gene and bipolar disorder. These results were also significant in the subgroups of bipolar I and early-onset (<18 years) bipolar disorder patients. No association with -93 A/G polymorphism was found. Haplotype analysis revealed that rs6916861 T/G and rs3730353 T/C polymorphisms are in linkage disequilibrium (r(2) = 0.86, D' = 0.93 with 95% CI = 0.9-0.97). The results suggest that the glutamatergic FYN gene may be associated with bipolar disorder, particularly with type I illness and early age of onset.

Chronic Paranoid Psychosis and Dementia Following Interferon-α Treatment of Hepatitis C: A Case Report

Low-dose interferon-alpha is a standard therapy for hepatitis C. Psychotic disorders have been described as a rare complication of such treatments that resolve with its termination. Here, we present a patient without significant risk factors for interferon-alpha-induced serious mental disorders who developed a psychotic disorder with a cognitive impairment achieving the level of dementia after seven months of interferon-alpha therapy. The disturbances have persisted for three years despite cessation of interferon and introduction of antipsychotic treatment. The possibility of severe neuropsychiatric adverse effects of interferon-alpha therapy in a susceptible individual may necessitate regular psychiatric consultations during the treatment.