A triptofán-hidroxiláz-2 gén polimorfizmusainak pszichogenetikai és molekuláris biológiai vizsgálata = Psychiatric and molecular biological aspects of the tryptophan hydroxylase-2 gene polymorphisms

A gyermekpszichiátriai gyakorlatban gyakran együttesen előforduló kórképek közös illetve egyedi genetikai rizikó faktorait elemeztük a figyelemhiányos hiperaktivitási zavar (ADHD: Attention Deficit Hyperactivity Disorder), a Tourette-szindróma (TS) és a kényszerbetegség (OCD: Obsessive Compulsive Disorder) összehasonlító genetikai vizsgálata során. E három kórkép közös neurobiológiai háttere feltehetően az agyi gátló körök funkciózavara illetve fejlődésbeli elmaradása, mely az ADHD impulzív tüneteit, a TS akaratlan mozgásait és hangadásit, illetve az OCD kényszer gondolatait és cselekvéseit okozza. Kandidáns gének a monoamin (dopamin és szerotonin) rendszerek elemeiből kerültek ki a bazális ganglionok és a prefrontális kortex érintettsége miatt. Közös genetikai rizikó faktorként a dopamin transzporter gén polimorfizmusának 10 ismétlődést tartalmazó allélját azonosítottuk. Ez a megfigyelés alátámasztja a dopamin neurotranszmisszió fontosságát a viselkedésgátlásban a bazális ganglionok szintjén mindhárom pszichiátriai zavarban. Egyedi genetikai rizikó faktorként a triptofán-hidroxiláz 2 gén rs4290270 polimorfizmusának A-allélja szerepelhet kényszergondolatok körében, mely a szerotonerg rendszer meghatározó szerepére mutat rá OCD-ben. ADHD betegek körében végzett farmakogenetikai elemzésünk a karboxilészteráz 1 gén jövőbeli vizsgálatára hívja fel a figyelmet, mivel a csökkent enzimaktivitású Glu-allélt hordozó betegek alacsonyabb metilfenidát adag mellett értek el tünetjavulást. | Comparative genetic analyses of Attention Deficit Hyperactivity Disorder (ADHD), Tourette-syndrome (TS), and Obsessive Compulsive Disorder (OCD) aimed to reveal common and specific genetic risk factors in these child psychiatric disorders. A common neurobiological origin is presumed, as the impulsivity in ADHD, the involuntary movements and vocalizations in TS, the obsessions and compulsions in OCD reflect immature inhibitory control of the thalamocortical circuits. Candidate genes were selected from the dopaminergic and serotonergic systems, because of their modulatory effects on the basal ganglia and prefrontal cortex. The 10-repeat allele of the dopamine transporter polymorphism was identified as a common genetic risk factor. This observation supports the importance of dopamine neurotransmission in the inhibitory control of the basal ganglia in all these three neurodevelopmental disorders. The A-allele of the rs4290270 polymorphism in the tryptophan hydroxylase 2 gene appeared as a specific genetic risk factor at obsession symptoms, which underlines the involvement of serotonergic system in OCD. Our pharmacogenetic studies of methylphenidate response pointed to the carboxylesterase 1 gene polymorphism, because ADHD patients carrying the low activity Glu-allele required less methylphenidate for achieving symptom reduction

A D4-es dopamin receptor gén 5' régiójának haplotípus szerkezete: molekuláris és pszichiátriai vonatkozások = Haplotype structure of the 5' region of the D4 dopamine receptor gene: molecular and psychiatric aspects

Napjaink egyik fő kutatási területe a poligénes rendellenességek (pl. pszichiátriai betegségek) genetikai hátterének elemzése. Munkánk során a Tourette-szindróma kialakulásában szerepet játszó genetikai tényezőket vizsgáltuk. Elsőként a D4-es dopamin receptor gén 5? nem kódoló régiójának polimorfizmusait elemeztük, mivel az itt található variációknak feltehetően hatása van a génexpresszióra, a D4-es dopamin receptor pedig a terápiás tapasztalatok alapján szerepet játszik a kórkép kifejlődésében. Munkánk első fő mérföldköve ezen polimorfizmusok (120 bp duplikáció, -616CG, -615AG és -521CT SNP polimorfizmusok) vizsgálatára alkalmas hatékony genotipizáló és haplotipizáló eljárások kidolgozása volt. Az SNP-ket a nagyobb megbízhatóság kedvéért két módszerrel elemeztük, a haplotípust direkt molekuláris technikákkal határoztuk meg. Mivel a Tourette-szindróma genetikai háttere meglehetősen komplex, a szerotonerg neurotranszmisszió fontosabb genetikai polimorfizmusait is bevontuk munkánkba. Egy új típusú variáció, a génszám polimorfizmus (CNV) vizsgálatára alkalmas technikákat is beállítottunk. Megállapítottuk, hogy a MAOA gén 5? régiójában lévő ismétlődési polimorfizmus asszociációt mutat a betegséggel. Emellett a kórkép jellegzetes tünete, a ticek súlyossága és a dopamin transzporter 3? polimorfizmusa között sikerült statisztikailag szignifikáns összefüggést kimutatni. Ezen polimorfizmusok a betegség genetikai rizikófaktorai lehetnek. | One of the most thoroughly investigated topics of today?s genetic research is the analysis of the background of complex, multifactorial (e.g. psychiatric) diseases. The goal of project was the study of those genetic components that might play a role in the development of Tourette-syndrome. The major target of our experiments was the variants in the 5? region of the dopamine D4 receptor gene, as these polymorphisms are supposed to contribute to gene expression regulation. The first milestone of our work was the elaboration of efficient techniques for the investigation of the genotype and haplotype of the 120 bp duplication, -616CG, -615AG and -521CT polymorphisms localized in this region. For higher reliability two independent methods were used for SNP analysis, the haplotype was determined by direct molecular techniques. As the background of Tourette-syndrome is rather complex, candidate genes of the serotonerg system were also involved in the study. Moreover novel methods were elaborated for the analysis of copy number variation (CNV) polymorphisms. It was demonstrated that 5? repeat polymorphism of the MAOA gene showed association with the illness, and connection was showed between a characteristic symptom, tic severity and the 3? polymorphism of dopamine transporter gene as well. Consequently these polymorphisms and genes might be genetic risk factors of Tourette-syndrome

Neurológiai és pszichiátriai betegségek in vitro modellezése indukált pluripotens őssejtek felhasználásával: fókuszban az Alzheimer-kór és a szkizofrénia

Over the past decade we witnessed the birth of a new scientific area that lies at the borders of developmental biology, stem cell biology, basic and clinical neuroscience. In vitro disease modeling refers to the approach that exploits the capacity of stem cells for self-renewal and pluripotency by generating specific cell types that are relevant for a given disorder. Based on this method, neurological and psychiatric disorders can be investigated by differentiating stem cells into neurons in a dish, and studying the relevant neuronal populations affected in the pathophysiology of the disorder in terms of specific cellular phenotypes. The advent of induced pluripotent stem cells (IPSCs) has made it possible to reprogram IPSCs from somatic cells of patients carrying specific genetic risk variants, and to analyze the in vitro cellular findings in the context of the clinical picture. Pluripotent stem cell based disease modeling offers an alternative solution for invasive and mostly not performable central nervous system biopsies in neuropsychiatric disorders, and is an appealing laboratory method for studying biomarkers of these disorders and for future drug development. This review summarizes the pluripotent stem cell based disease modeling literature in two important neuropsychiatric disorders, Alzheimer's disease and schizophrenia

Polymorphism in the serotonin receptor 2a (HTR2A) gene as possible predisposal factor for aggressive traits

Aggressive manifestations and their consequences are a major issue of mankind, highlighting the need for understanding the contributory factors. Still, aggression-related genetic analyses have so far mainly been conducted on small population subsets such as individuals suffering from a certain psychiatric disorder or a narrow-range age cohort, but no data on the general population is yet available. In the present study, our aim was to identify polymorphisms in genes affecting neurobiological processes that might explain some of the inter-individual variation between aggression levels in the non-clinical Caucasian adult population. 55 single nucleotide polymorphisms (SNP) were simultaneously determined in 887 subjects who also filled out the self-report Buss-Perry Aggression Questionnaire (BPAQ). Single marker association analyses between genotypes and aggression scores indicated a significant role of rs7322347 located in the HTR2A gene encoding serotonin receptor 2a following Bonferroni correction for multiple testing (p = 0.0007) both for males and females. Taking the four BPAQ subscales individually, scores for Hostility, Anger and Physical Aggression showed significant association with rs7322347 T allele in themselves, while no association was found with Verbal Aggression. Of the subscales, relationship with rs7322347 was strongest in the case of Hostility, where statistical significance virtually equaled that observed with the whole BPAQ. In conclusion, this is the first study to our knowledge analyzing SNPs in a wide variety of genes in terms of aggression in a large sample-size non-clinical adult population, also describing a novel candidate polymorphism as predisposal to aggressive traits

A dopamin és a szerotonin rendszer promoter polimorfizmusainak molekuláris biológiája és pszichogenetikai vonatkozásai = Molecular biology and psychogenetic aspects of the promoter polymorphisms in the dopaminergic and serotonergic systems

A dopamin rendszer közismerten kulcsszerepet játszik a kognitív funkciókban, ezért a dopaminerg neurotranszmisszió komponensei a pszichogenetikai kutatások középpontjában állnak. Jelen vizsgálatunkban molekuláris biológiai eszközökkel részletesen jellemeztük a dopamin D4-es receptor (DRD4) promoter régiójának polimorfizmusait. Megállapítottuk, hogy a DRD4 promoter 120 bázispár duplikáció transzkripciót csendesítő (silencer) hatású, valamint bizonyítottuk, hogy a duplikáció hiánya a figyelemhiányos hiperaktivitási zavar (ADHD) rizikófaktora. Kimutattuk továbbá, hogy a DRD4 gén 3. exonjában előforduló ismétlési polimorfizmus 7-es alléljával rendelkező egészséges felnőtt személyek átlagos teljesítménye alacsonyabb a kitartó figyelmet igénylő feladatokban a 7-es allélal nem rendelkező társaikhoz viszonyítva. A dopamint bontó COMT alacsonyabb aktivitású (magasabb dopamin szint) Met-variánsát egyes adatok a jobb felnőttkori kognitív teljesítménnyel hozzák összefüggésbe, a korai életszakaszra azonban kevés az adat. Külföldi kollaborációban kimutattuk, hogy a COMT Met/Met genotípusú csecsemők figyelme kevésbé terelhető el, mint a Val/VAl genotípusúaké az úgynevezett "Freeze-Frame" próbákban. Vizsgáltuk továbbá a hipnotikus fogékonyságot, mely vonás összefüggésben áll a kognitív figyelmi szűréssel, és kimutattuk, hogy a COMT Met allél növeli a hipnózis iránti érzékenységet felnőttkorban. Eredményeink hozzájárulnak a kognitív funkciók molekuláris alapjainak mélyebb megértéséhez. | The central role of the dopamine system in cognitive functions is well known, thus components of the dopaminergic neurotransmission is a key topic in psychogenetic studies. In the present study molecular biological methods were used for detailed characterization of polymorphisms in the promoter region of the dopamine D4 receptor. Our results indicate that the 120 basepair duplication in the promoter region of the DRD4 has a transcriptional silencer effect, and the lack of the duplication is a risk factor of attention deficit hyperactivity disorder (ADHD). Moreover, we demonstrated that cognitive performance of healthy adults was lower in sustained attention tasks if they carried the 7-repeat allele of the DRD4 gene. The high activity Met-variant of the COMT was previously shown to associate with better cognitive performance in healthy adults, however, data from earlier age is limited. In international collaboration we found that infants with the Met/Met genotype were significantly less distractible in Freeze-Frame trials than infants with the Val/Val genotype. We also investigated hypnotic susceptibility, a trait in close connection with selective attention, in adults, and found an association with the COMT Val/Met polymorphism. These results support a better understanding of the molecular basis of cognitive functions

Association between dopaminergic polymorphisms and borderline personality traits among at-risk young adults and psychiatric inpatients

Background: In the development of borderline personality disorder (BPD) both genetic and environmental factors have important roles. The characteristic affective disturbance and impulsive aggression are linked to imbalances in the central serotonin system, and most of the genetic association studies focused on serotonergic candidate genes. However, the efficacy of dopamine D2 receptor (DRD2) blocking antipsychotic drugs in BPD treatment also suggests involvement of the dopamine system in the neurobiology of BPD.Methods: In the present study we tested the dopamine dysfunction hypothesis of impulsive self- and other-damaging behaviors: borderline and antisocial traits were assessed by Structured Clinical Interview for Diagnosis (SCID) for DSM-IV in a community-based US sample of 99 young adults from low-to-moderate income families. For the BPD trait analyses a second, independent group was used consisting of 136 Hungarian patients with bipolar or major depressive disorder filling out self-report SCID-II Screen questionnaire. In the genetic association analyses the previously indicated polymorphisms of the catechol-O-methyl-transferase (COMT Val158Met) and dopamine transporter (DAT1 40 bp VNTR) were studied. In addition, candidate polymorphisms of the DRD2 and DRD4 dopamine receptor genes were selected from the impulsive behavior literature.Results: The DRD2 TaqI B1-allele and A1-allele were associated with borderline traits in the young adult sample (p = 0.001, and p = 0.005, respectively). Also, the DRD4 -616 CC genotype appeared as a risk factor (p = 0.02). With severity of abuse accounted for in the model, genetic effects of the DRD2 and DRD4 polymorphisms were still significant (DRD2 TaqIB: p = 0.001, DRD2 TaqIA: p = 0.008, DRD4 -616 C/G: p = 0.002). Only the DRD4 promoter finding was replicated in the independent sample of psychiatric inpatients (p = 0.007). No association was found with the COMT and DAT1 polymorphisms.Conclusions: Our results of the two independent samples suggest a possible involvement of the DRD4 -616 C/G promoter variant in the development of BPD traits. In addition, an association of the DRD2 genetic polymorphisms with impulsive self-damaging behaviors was also demonstrated. © 2010 Nemoda et al; licensee BioMed Central Ltd

Genetikai és környezeti hatások kölcsönhatása a csecsemőkori kötődés alakulásában = Interaction of genetic and environmental influences in the development of infant attachment

Vizsgáltuk a genetikai és a környezeti tényezők hatásait, valamint a gén-környezet kölcsönhatást a korai kötődés jellemzőire. Fontosabb eredményeink: 1. A családi genotípusok és az öröklésmenet vizsgálatával megerősítettük az elsőszülött csecsemők DRD4 genotípusának és anyához való kötődésének asszociációját. A kötődés és a szülői DRD4 genotípusok között nincs összefüggés (Gervai et al., 2005). 2. Kimutattuk, hogy a BCsV elsőszülött csecsemők szülőkhöz való kötődése között szignifikáns egyezés van, és az apához való kötődés biztonsága összefügg a csecsemő DRD4 genotípusával (Tóth et al., előkészületben). 3. Kimutattuk, hogy a szerotonin transzporter gén 5-HTTLPR genotípusa nem függ össze a kötődéssel, de a DRD4 genotípussal együtt hat az idegenfélelem mértékére (Lakatos et al., 2003). 4. Kidolgoztuk a magyar kisgyermekes családokban a jelentős életesemények súlyozásának módját (Danis et al., elfogadva). Becsültük a környezeti stressz mértékét a csecsemők első életévére (Danis et al., előkészületben). 5. Kimutattuk a dezorganizált kötődés és az atipikus anyai viselkedés kapcsolatát és felfedeztük a csecsemők DRD4 genotípusának módosító hatását. A DRD4 gén 7-ismétlésű változatának hiányában az anyai atipikus viselkedés összefügg a dezorganizált kötődéssel, a 7-ismétlésű változatot hordozó csecsemők azonban érzéketlenek az anyai viselkedés atipikusságára. Az eredményeket közlő cikket meghívták a Social Neuroscience különszámába (Gervai et al., közlésre benyújtva). | The research concerned genetic and environmental effects on infant attachment, and gene-environment interactions. 1. We confirmed the association of firstborn infants? DRD4 genotype and attachment to the mother by examining family genotypes and the pattern of allele transmissions. Parental DRD4 genotypes were not associated with infant attachment (Gervai et al., 2005). 2. We found a significant association between infant attachment to the parents. Further, security of attachment to the father was associated with the infant?s DRD4 genotype (Tóth et al., in prep). 3. The 5-HTTLPR repeat polymorphism of the serotonin transporter promoter region was not associated with infant attachment, but together with the DRD4 genotype it affected the degree of stranger fear (Lakatos et al., 2003). 4. We obtained Hungarian weights for significant life events in families with young children (Danis et al., accepted). Using these, we estimated life-stress for the first year of infants? life (Danis et al., in prep). 5. We found an association between disorganized attachment and atypical maternal behavior, which was moderated by infant genotype. In the absence of the DRD4 7-repeat allele, atypical maternal behavior was strongly related to infant disorganization, but infants with the 7-repeat allele were insensitive to maternal atypical behavior. The paper describing the results was invited for publication in Social Neuroscience (Gervai et al., submitted)

Potential salivary biomarkers and their genetic effects in a pilot study of adolescent boys with externalizing problems.

AIMS: Beside the well-known stress response marker cortisol, salivary alpha-amylase is receiving increasing attention. Numerous studies have investigated the potential biomarker properties of cortisol mirroring abnormal hypothalamic-pituitary-adrenal axis activity in connection to both internalizing and externalizing behavior problems. The other major physiological system involved in stress reactivity, the sympathetic nervous system activity can be also measured by the surrogate marker of salivary alpha-amylase. Most of the studies applied a stressful situation to obtain inter-individual differences in stress-reactivity, although differences in the baseline level of cortisol have been also shown in relation to externalizing problems. To test the relevance of another (easier) biomarker, we selected to study baseline circadian salivary cortisol and alpha-amylase levels among adolescent boys with externalizing problems. METHODS: Saliva samples were collected at 3 time-points (morning, noon, evening) during 3 consecutive days from 37 inpatient boys (mean age 12.4+/-1.0). Cortisol and alpha-amylase levels were measured by enzyme-linked immunosorbent and kinetic enzyme assays, respectively. Genetic variants in the hypothalamic-pituitary-adrenal axis and the norepinephrine transporter or catecholamine metabolizing enzymes were tested for potential moderating effects at these salivary biomarkers. RESULTS: Saliva cortisol showed the classical diurnal fluctuation in boys with externalizing problems (possibly from a lower morning level), but it was not modified by the presence of either conduct, oppositional defiant or attention-deficit/hyperactivity disorder. The diurnal fluctuation of the salivary alpha-amylase levels was also typical, but the presence of conduct disorder was associated with significantly lower alpha-amylase activity (p=0.024) among boys with externalizing problems. The catechol-O-methyltransferase Val158Met (rs4680) polymorphism had an additional effect on salivary alpha-amylase: boys with homozygote genotypes had lower alpha-amylase activity at all 3 time-points compared to Val/Met heterozygotes (p=0.045). CONCLUSIONS: Our preliminary data suggest that salivary alpha-amylase might be used to further characterize subgroups within externalizing problems, however, this biomarker might be modified by certain genetic polymorphisms

Attachment and temperament revisited: infant distress, attachment disorganisation and the serotonin transporter polymorphism

Objective: This study’s aim was to evaluate whether infant disorganised attachment and infant proneness to distress exhibited differential relations to infant genetic factors as indexed by the serotonin transporter polymorphism. Background: The role of the short allele of the serotonin transporter polymorphism (5-HTTLPR) in enhancing sensitivity to fearful and negative affect has been well-established. In the current study, we used this known property of the short allele to provide a test of an important postulate of attachment theory, namely that infant attachment security or disorganisation is not a function of the infant’s proneness to distress. Methods: Participants were 39 parents and infants assessed between 12 and 18 months in the Strange Situation Procedure. Genotype categories for the 5-HTTLPR (and rs25531) were created by both the original and the reclassified grouping system; infant proneness to distress was assessed directly in the Strange Situation Procedure. We also assessed maternal behaviour at 18 months to evaluate whether any observed genetic effect indicated a passive effect through the mother. Results: Consistent with previous findings, the 5-HTTLPR short allele was significantly related to the infant’s wariness and distress, but was not related to attachment security or attachment disorganisation. In addition, maternal disrupted interaction with the infant was not related to infant genotype or infant distress. Conclusion: Results support the concept that infant proneness to distress is associated with serotonergic factors while infant attachment security or disorganisation is not a function of either 5-HTTLPR or behaviourally rated proneness to distress. © 2015 Society for Reproductive and Infant Psychology

Association of purinergic receptor P2RX7 gene polymorphisms with depression symptoms

The activation of the ATP-gated P2RX7 (purinergic receptor P2X, ligand-gated ion channel, 7) produces microglial activation, a process which has been demonstrated in depression, bipolar disorder, and schizophrenia. Emerging data over the last years highlighted the importance of P2X7 cation channel as a potential drug target for these central nervous system disorders. The Gln460Arg (rs2230912) polymorphism of the P2RX7 gene has been widely studied in mood disorders, however the results are still controversial. Therefore, we aimed to investigate the C-terminal region of this gene in major depressive and bipolar disorders (MDD and BD) by studying possibly functional, non-synonymous polymorphisms within a 7 kb long region around the Gln460Arg, including Ala348Thr (rs1718119), Thr357Ser (rs2230911), and Glu496Ala (rs3751143) variants. Since Gln460Arg is located at the 3' end of the P2RX7 gene, we included additional, potentially functional single nucleotide polymorphisms (SNPs) from the 3' untranslated region (UTR), which can be in linkage with Gln460Arg. Based on in silico search, we chose two SNPs in putative microRNA target sites which are located in consecutive positions: rs1653625 and rs1718106.P2RX7 SNPs from the C-terminal region were selected based on previous functional assays, 3' UTR variants were chosen using PolymiRTS and Patrocles databases. The genotyping of the non-synonymous SNPs was carried out by pre-designed TaqMan® kits, while the 3' UTR variants were analyzed by PCR-RFLP method. Case-control analyses were carried out between 315 inpatients with acute major depressive episode (195 MDD, 120 BD) and 406 healthy control subjects. The two subscales of the Hospital Anxiety and Depression Scale (HADS) self-report questionnaire were used for quantitative analyses, including an additional, "at-risk" population of 218 patients with diabetes mellitus. The in vitro reporter gene assays were carried out on HEK and SK-N-FI cells transiently transfected with pMIR vector constructs containing the P2RX7 3' UTR downstream of the luciferase gene.Haplotype analysis indicated a relatively high linkage between the analyzed P2RX7 SNPs. Our case-control study did not yield any association between P2RX7 gene variants and depression. However, dimensional analyses showed significant associations of the HADS depression severity scores with Gln460Arg (rs2230912) and Ala348Thr (rs1718119) in the depressed and diabetic patient groups. In the in vitro experiments, the P2RX7 3' UTR constructs with the lowest predicted binding efficiency to their miRNAs showed the highest expression of the gene. The combination of the depression-associated P2RX7 C-terminal and 3' UTR SNPs contributed to the highest depression severity score in the haplotype analysis. Based on our findings, we propose that a P2RX7 haplotype combination of the Gln460Arg and neighboring SNPs contribute to the observed genetic association with depressive symptoms