Differential methylation of imprinting genes and MHC locus in 22q11.2 deletion syndrome-related schizophrenia spectrum disorders.

OBJECTIVES: 22q11.2 deletion syndrome (DS) is the strongest known genetic risk for schizophrenia. Methylome screening was conducted to elucidate possible involvement of epigenetic alterations in the emergence of schizophrenia spectrum disorders (SZ-SD) in 22q11.2DS. METHODS: Sixteen adult men with/without SZ-SD were recruited from a 22q11.2DS cohort and underwent genome-wide DNA methylation profile analysis. Differentially methylated probes (DMPs) and regions (DMRs) were analysed using the ChAMP software. RESULTS: The DMPs (p-value <10-6) and DMRs (p-valueArea <0.01) were enriched in two gene sets, 'imprinting genes' and 'chr6p21', a region overlapping the MHC locus. Most of the identified imprinting genes are involved in neurodevelopment and located in clusters under imprinting control region (ICR) regulation, including PEG10, SGCE (7q21.3), GNAS, GNAS-AS1 (20q13.32) and SNHG14, SNURF-SNRPN, SNORD115 (15q11.2). The differentially methylated genes from the MHC locus included immune HLA-genes and non-immune genes, RNF39, PPP1R18 and NOTCH4, implicated in neurodevelopment and synaptic plasticity. The most significant DMR is located in MHC locus and covered the transcription regulator ZFP57 that is required for control and maintenance of gene imprinting at multiple ICRs. CONCLUSIONS: The differential methylation in imprinting genes and in chr6p21-22 indicate the neurodevelopmental nature of 22q11.2DS-related SZ and the major role of MHC locus in the risk to develop SZ.

V-groove-shaped silicon-on-insulator photopolarized activated modulator (SOIP2AM): a polarizing transistor.

In this paper, we present the design of a silicon optoelectronic device capable of speeding up processing capabilities. The data in this device are electronic, while the modulation control is optical. It can be used as a building block for the development of optical data processing by silicon-based processors based on typical microelectronics manufacturing processes. A V-groove-based structure fabricated as part of the device allows obtaining enhanced sensitivity to the polarization of the photonic control signal and thus allows obtaining a polarization-sensitive modulator.

Risk gene-set and pathways in 22q11.2 deletion-related schizophrenia: a genealogical molecular approach.

The 22q11.2 deletion is a strong, but insufficient, "first hit" genetic risk factor for schizophrenia (SZ). We attempted to identify "second hits" from the entire genome in a unique multiplex 22q11.2 deletion syndrome (DS) family. Bioinformatic analysis of whole-exome sequencing and comparative-genomic hybridization array identified de novo and inherited, rare and damaging variants, including copy number variations, outside the 22q11.2 region. A specific 22q11.2-haplotype was associated with psychosis. The interaction of the identified "second hits" with the 22q11.2 haploinsufficiency may affect neurodevelopmental processes, including neuron projection, cytoskeleton activity, and histone modification in 22q11.2DS-ralated psychosis. A larger load of variants, involved in neurodevelopment, in combination with additional molecular events that affect sensory perception, olfactory transduction and G-protein-coupled receptor signaling may account for the development of 22q11.2DS-related SZ. Comprehensive analysis of multiplex families is a promising approach to the elucidation of the molecular pathophysiology of 22q11.2DS-related SZ with potential relevance to treatment.

Runs of homozygosity, copy number variation, and risk for depression and suicidal behavior in an Arab Bedouin kindred.

OBJECTIVES: Inbreeding increases the probability of homozygosity of deleterious alleles. Inbreeding and runs of homozygosity (ROH) are associated with an increased risk for disease phenotypes, including schizophrenia and other psychiatric disorders. The effects of inbreeding, ROH, homozygous deletions, and other copy number variations (CNVs) on risk for depression and suicide attempt (SA) were quantified in an Arab Bedouin Kindred. METHODS: We carried out genetic analyses of 439 individuals from an Arab kindred with high rates of depression and suicidal behavior. We obtained complete ascertainment of SAs and first-degree relatives of individuals who have attempted or died by suicide. RESULTS: We found extensive regions of ROH. On average, 5% of the genome is covered by ROH for these individuals, two-fold higher than ROH rates for individuals from populations of European ancestry. Inbreeding and total length of ROH were not associated with risk for depression or attempt. For CNVs, an increased number of duplications more than 500 kb was associated with an increased risk for attempt (odds ratio: 2.9; P=0.01; 95% confidence interval: 1.3-6.6). Although not significant after correction for multiple testing, the risk for SA appears to increase with copy number for a CNV on chromosome 9p24.1. This possibility is intriguing because the CNV covers GLDC, which encodes glycine dehydrogenase that binds to glycine, a co-agonist at N-methyl-D-aspartate glutamate receptors, and is involved in glutamatergic neurotransmission. CONCLUSION: Our findings add to the growing evidence of genetic risk factors that act pleiotropically to increase the risk for several neuropsychiatric disorders, including depression and SA, irrespective of ancestry.

Pharmacogenetics of citalopram-related side effects in children with depression and/or anxiety disorders.

Pharmacogenetic approach to antidepressant (AD) response is a promising avenue toward individualizing AD treatment. This is particularly relevant in pediatric populations because of concerns about the suicide risk of serotonin selective reuptake inhibitors (SSRIs), resulting in a black-box warning. However, to date, no specific gene or polymorphism has been consistently implicated as a marker of AD side effect (SE) in the pediatric population. The aim of this study was to examine the association between polymorphisms in genes related to the serotonergic system and citalopram SE's in children and adolescents with major depressive disorder (MDD)/dysthymia and/or anxiety disorders. Outpatients (N = 87, 44 % males), aged 7-18 years with a DSM-IV-TR diagnosis of MDD/dysthymia and/or an anxiety disorder were treated in an 8-week open trial with 20-40 mg/day of citalopram. SE's were rated using a questionnaire devised specifically for this study. Association analysis between known/candidate genetic variants in three genes (5-HTR2A, 5-HTR1Dß, 5-HTR2C) and SE's was conducted. Agitation was more common in boys than girls (male:female 42.1 vs. 18.7 %, χ 2 = 5.61, df = 1, p = 0.018). Subjects with 5-HTR1Dß CC genotype showed more agitation vs. both CG and GG genotypes (CC:CG:GG 71.4 vs. 33.3 vs. 18.1 %, χ 2 = 8.99, df = 2, p = 0.011). The 5-HTR1Dß CC genotype was associated with more reports of agitation. It has been suggested that agitation may be an intermediate phenotype to suicidal behavior. Thus, it seems that 5-HTR1Dß polymorphism may be involved in citalopram-related agitation in children and adolescents treated for depression and/or anxiety.

CHRNA5/A3/B4 Variant rs3743078 and Nicotine-Related Phenotypes: Indirect Effects Through Nicotine Craving.

OBJECTIVE: Nicotine craving is considered an important element in the persistence of cigarette smoking, but little is known about the role of craving in the widely recognized association between variants mapped to the neuronal nicotinic acetylcholine receptor (CHRN) genes on chromosome 15 and nicotine phenotypes. METHOD: The associations between CHRNA5-CHRNA3-CHRNB4 variants and cigarettes per day (CPD), the Fagerström Test for Nicotine Dependence (FTND), and craving were analyzed in data from 662 lifetime smokers from an Israeli adult Jewish household sample. Indirect effects of genotype on nicotine phenotypes through craving were formally tested using regression and bootstrapping procedures. RESULTS: At CHRNA3, allele G of rs3743078 was associated with increased craving, CPD, and FTND scores: Participants with one or two copies of the G allele had, on average, higher scores on the craving scale (p = .0025), more cigarettes smoked (p = .0057), and higher scores on the FTND (p =.0024). With craving in the model, variant rs3743078 showed a significant indirect effect through craving on CPD (p = .0026) and on FTND score (p = .0024). A sizeable proportion of the total rs3743078 effect on CPD (56.4%) and FTND (65.2%) was indirect through craving. CONCLUSIONS: These results suggest that nicotine craving may play a central role in nicotine use disorders and may have utility as a therapeutic target.

Thymic and bone marrow output in individuals with 22q11.2 deletion syndrome.

BACKGROUND: The 22q11.2 deletion syndrome (22q11.2DS) is a congenital multisystem anomaly characterized by typical facial features, palatal anomalies, congenital heart defects, hypocalcemia, immunodeficiency, and cognitive and neuropsychiatric symptoms. The aim of our study was to investigate T- and B-lymphocyte characteristics associated with 22q11.2DS. METHODS: Seventy-five individuals with 22q11.2DS were tested for T and B lymphocytes by examination of T-cell receptor rearrangement excision circles (TRECs) and B-cell κ-deleting recombination excision circles (KRECs), respectively. RESULTS: The 22q11.2DS individuals displayed low levels of TRECs, while exhibiting normal levels of KRECs. There was a significant positive correlation between TREC and KREC in the 22q11.2DS group, but not in controls. Both TREC and KREC levels showed a significant decrease with age and only TREC was low in 22q11.2DS individuals with recurrent infections. No difference in TREC levels was found between 22q11.2DS individuals who underwent heart surgery (with or without thymectomy) and those who did not. CONCLUSION: T-cell immunodeficiency in 22q11.2DS includes low TREC levels, which may contribute to recurrent infections in individuals with this syndrome. A correlation between T- and B-cell abnormalities in 22q11.2DS was identified. The B-cell abnormalities could account for part of the immunological deficiency seen in 22q11.2DS.

Hyperactive auditory processing in Williams syndrome: Evidence from auditory evoked potentials.

The neurophysiologic aberrations underlying the auditory hypersensitivity in Williams syndrome (WS) are not well defined. The P1-N1-P2 obligatory complex and mismatch negativity (MMN) response were investigated in 18 participants with WS, and the results were compared with those of 18 age- and gender-matched typically developing (TD) controls. Results revealed significantly higher amplitudes of both the P1-N1-P2 obligatory complex and the MMN response in the WS participants than in the TD controls. The P1-N1-P2 complex showed an age-dependent reduction in the TD but not in the WS participants. Moreover, high P1-N1-P2 complex was associated with low verbal comprehension scores in WS. This investigation demonstrates that central auditory processing is hyperactive in WS. The increase in auditory brain responses of both the obligatory complex and MMN response suggests aberrant processes of auditory encoding and discrimination in WS. Results also imply that auditory processing may be subjected to a delayed or diverse maturation and may affect the development of high cognitive functioning in WS.

Childhood adversity moderates the effect of ADH1B on risk for alcohol-related phenotypes in Jewish Israeli drinkers.

Childhood adversity and genetic variant ADH1B-rs1229984 have each been shown to influence heavy alcohol consumption and disorders. However, little is known about how these factors jointly influence these outcomes. We assessed the main and additive interactive effects of childhood adversity (abuse, neglect and parental divorce) and the ADH1B-rs1229984 on the quantitative phenotypes 'maximum drinks in a day' (Maxdrinks) and DSM-Alcohol Use Disorder (AUD) severity, adjusting for demographic variables, in an Israeli sample of adult household residents (n = 1143) evaluated between 2007 and 2009. Childhood adversity and absence of the protective ADH1B-rs1229984 A allele were associated with greater mean Maxdrinks (mean differences: 1.50; 1.13, respectively) and AUD severity (mean ratios: 0.71; 0.27, respectively). In addition, childhood adversity moderated the ADH1B-rs1229984 effect on Maxdrinks (P < 0.01) and AUD severity (P < 0.05), in that there was a stronger effect of ADH1B-rs1229984 genotype on Maxdrinks and AUD severity among those who had experienced childhood adversity compared with those who had not. ADH1B-rs1229984 impacts alcohol metabolism. Therefore, among those at risk for greater consumption, e.g. those who experienced childhood adversity, ADH1B-rs1229984 appears to have a stronger effect on alcohol consumption and consequently on risk for AUD symptom severity. Evidence for the interaction of genetic vulnerability and early life adversity on alcohol-related phenotypes provides further insight into the complex relationships between genetic and environmental risk factors.

Parental alcohol history differentially predicts offspring disorders in distinct subgroups in Israel.

OBJECTIVE: The association between alcoholism in parents and related disorders in their offspring is well established in cultures with intermediate/high alcohol consumption, but not in those with low consumption, such as Israel. This study investigated differences in parental transmission of alcohol problems and related psychopathology between immigrants from the former Soviet Union (FSU) to Israel and other Israelis-two Israeli subgroups with differing alcohol consumption behaviors and social norms. METHOD: A total of 1,347 adults from a household sample were interviewed. Regression analyses were used to examine associations between parental alcohol problems and participant disorders: alcohol, nicotine, and cannabis use disorders (AUD, NUD, CUD); antisocial personality disorder (ASPD); major depressive disorder (MDD); and posttraumatic stress disorder (PTSD). We also examined the associations of parental alcohol problems with participant disorders characterized with two latent factors: externalizing (EXT: AUD, NUD, CUD, ASPD) and internalizing (INT: MDD, PTSD). Differential parental transmission of alcohol problems in FSU (n = 315) and non-FSU (n = 1,032) Israelis was examined with statistical interaction. RESULTS: Among emigrants from the FSU, parental alcohol problems predicted AUD, NUD, CUD, ASPD, PTSD, EXT, and INT (mean ratios = 1.38-4.83). In non-FSU Israelis, parental alcohol problems predicted only ASPD and PTSD (mean ratios = 1.08-4.09). Significant interactions were observed for AUD, CUD, PTSD, and EXT; each relationship was stronger in FSU Israelis and null (AUD, CUD, EXT) or less robust (PTSD) in other Israelis. CONCLUSIONS: Parental alcohol problems were related to substance use and psychiatric disorders differently in FSU and other Israelis, two groups with different alcohol consumption levels and drinking norms. We propose that, in social contexts that vary in the degree to which they constrain alcohol behavior, underlying genetic predispositions may manifest as different disorders.

Alcohol consumption mediates the relationship between ADH1B and DSM-IV alcohol use disorder and criteria.

OBJECTIVE: A single nucleotide variation in the alcohol dehydrogenase 1B (ADH1B) gene, rs1229984, produces an ADH1B enzyme with faster acetaldehyde production. This protective variant is associated with lower alcohol consumption and lower risk for alcohol use disorders (AUDs). Based on the premise that faster ADH1B kinetics decreases alcohol consumption, we formally tested if the association between ADH1B variant rs1229984 and AUDs occurs through consumption. We also tested whether the association between rs1229984 and each of the 11 Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), AUD criteria occurs through consumption. METHOD: A total of 1,130 lifetime drinkers from an Israeli household sample were assessed with a structured interview and genotyped for rs1229984 (protective allele frequency = 0.28). Logistic regression evaluated the association between rs1229984 and each phenotype (AUDs, 11 individual DSM-IV criteria). For phenotypes significantly related to rs1229984, the effect through consumption was tested with logistic regression and bootstrapping. RESULTS: ADH1B rs1229984 was significantly associated with AUDs and six criteria, with odds ratios ranging from 1.32 to 1.96. The effect through consumption was significant for these relationships, explaining 23%-74% of the total ADH1B effect. CONCLUSIONS: This is the first study to show that ADH1B rs1229984 is related to 6 of the 11 DSM-IV AUD criteria and that alcohol consumption explained a significant proportion of these associations and the association of ADH1B with AUDs. Better understanding of the relationship between ADH1B and the DSM-IV AUD criteria, including effects through consumption, will enhance our understanding of the etiologic model through which AUDs can occur.

Parental psychopathology moderates the influence of parental divorce on lifetime alcohol use disorders among Israeli adults.

BACKGROUND: Parental divorce and psychopathology are well-documented risk factors for alcohol use disorders (AUD) in the United States and other countries where divorce is common and per capita total alcohol consumption is moderate to high. However, little is known about these relationships in countries where divorce and alcohol problems are less common, such as Israel. METHODS: Israeli adult household residents (N=797) age 21-45 were interviewed in person between 2007 and 2009. Logistic regression models were used to examine main and additive interaction effects of parental divorce and psychopathology on lifetime DSM-IV AUD, adjusting for age, gender, and ethnicity. RESULTS: Parental divorce (OR=2.18, p≤0.001) and parental psychopathology (OR=1.61, p≤0.01) were independently associated with lifetime AUD and, when considered together, showed significant interaction (p=0.026). Specifically, the effect of divorce on AUD was only significant among those who also reported parental psychopathology. CONCLUSIONS: This is the first study showing the influence of parental divorce and psychopathology on risk for AUD among Israeli adults, where both divorce and AUD are less common than in the United States. Alcohol prevention and treatment professionals should recognize that children who experience parental divorce and/or psychopathology could be more vulnerable to later developing AUD than those whose parents remain together and without psychopathology.

Association of COMT and PRODH gene variants with intelligence quotient (IQ) and executive functions in 22q11.2DS subjects.

The 22q11.2 deletion syndrome (22q11.2DS) carries the highest genetic risk factor for the development of schizophrenia. We investigated the association of genetic variants in two schizophrenia candidate genes with executive function (EF) and IQ in 22q11.2DS individuals. Ninety two individuals with 22q11.2 deletion were studied for the genetic association between COMT and PRODH variants and EF and IQ. Subjects were divided into children (under 12 years old), adolescents (between 12 and 18 years old) and adults (older than 18 years), and genotyped for the COMT Val158Met (rs4680) and PRODH Arg185Trp (rs4819756) polymorphisms. The participants underwent psychiatric evaluation and EF assessment. Our main finding is a significant influence of the COMT Val158Met polymorphism on both IQ and EF performance. Specifically, 22q11.2DS subjects with Met allele displayed higher IQ scores in all age groups compared to Val carriers, reaching significance in both adolescents and adults. The Met allele carriers performed better than Val carriers in EF tasks, being statistically significant in the adult group. PRODH Arg185Trp variant did not affect IQ or EF in our 22q11.2DS cohort. In conclusion, functional COMT variant, but not PRODH, affects IQ and EF in 22q11.2DS subjects during neurodevelopment with a maximal effect at adulthood. Future studies should monitor the cognitive performance of the same individuals from childhood to old age.

[Pharmacogenetics and anxiety disorders: analysis of recent findings].

Anxiety disorders are chronic disorders appearing with a high frequency in the general population and causing much distress to those suffering from them. The current common treatment consists of antidepressants, primarily from the serotonin-selective-reuptake-inhibitor (SSRI) class. However, despite the relative effectiveness of these medications the patients' responses vary widely with one third not responding at all. While we do not currently have the ability to predict who will respond positively to the medication, it is hoped that genetic research will make it possible to prospectively identify responders and thus help avoid failed treatment attempts and side-effects. The field of pharmacogenetics is divided into pharmaco-kinetics (genetic factors that influence the drug metabolism in the body) and pharmco-dynamics (genetic factors that affect the response to the drug at the level of the receptors/transporters/enzymes in the target organs). Contrary to the treatment of depression, there is little research available on the pharmacogenetics of anxiety disorders and the existing research coincides with the studies on depression. The primary pharmacogenetic-dynamic findings are related to serotonergic genes of which those with the long allele of the serotonin transporter gene (5-HTTLPR) are expected to respond positively to treatment, and the same is true regarding genetic variants of several serotonin receptors. The pharmacogenetic-kinetic findings focus on the CYP450 enzyme system. The hope is that with the progression of the pharmacogenetic research new genetic variants will be discovered which, when combined with the clinical characteristics of those suffering from anxiety disorders, will enable the development of novel treatment algorithms to be customized for each patient.

Shyness discriminates between children with 22q11.2 deletion syndrome and Williams syndrome and predicts emergence of psychosis in 22q11.2 deletion syndrome.

BACKGROUND: 22q11.2 deletion syndrome (22q11.2DS) is a common neurogenetic syndrome associated with high rates of psychosis. The aims of the present study were to identify the unique temperament traits that characterize children with 22q11.2DS compared to children with Williams syndrome (WS) and typically developing (TD) controls, and to examine temperamental predictors of the emergence of psychosis in 22q11.2DS. METHODS: The temperament of 55 children with 22q11.2DS, 36 with WS, and 280 TD children was assessed using the Emotionality, Activity, Sociability (EAS) Temperament Survey, Parental Ratings. The presence of a psychotic disorder was evaluated in 49 children and adolescents with 22q11.2DS at baseline and again 5.43 ± 2.23 years after baseline temperament assessment. RESULTS: Children with 22q11.2DS scored higher on Shyness compared to WS and TD controls. Children with 22q11.2DS and WS scored higher on Emotionality and lower on Activity compared to TD controls. Shyness was more severe in older compared to younger children with 22q11.2DS. Baseline Shyness scores significantly predicted the later emergence of a psychotic disorder at follow-up, in children with 22q11.2DS. CONCLUSIONS: Our results suggest that shyness is an early marker associated with the later emergence of psychosis in 22q11.2DS.

Trauma exposure, posttraumatic stress disorder and risk for alcohol, nicotine, and marijuana dependence in Israel.

BACKGROUND: Substance dependence is more common among trauma-exposed individuals; however, most studies suggest that Posttraumatic Stress Disorder (PTSD) accounts for the link between trauma exposure (TE) and substance dependence. OBJECTIVES: This study examined associations between TE and substance dependence (alcohol, nicotine, and marijuana), and whether PTSD accounted for this association. METHOD: 1317 Jewish Israeli household residents completed in-person structured interviews assessing TE, PTSD, and substance (alcohol, nicotine, marijuana) dependence between 2007 and 2009. Regression analyses examined associations among TE, PTSD, and substance dependence. RESULTS: In the full sample, mean number of traumatic events was 2.7 (sd=2.2), with 83.7% experiencing at least one event. In the full sample, mean number of PTSD symptoms was 2.5 (sd=3.4), with 13.5% meeting PTSD diagnostic criteria. Prevalence of alcohol dependence was 13.4%; nicotine dependence 52.8%; and marijuana dependence 12.1%. Number of traumatic events was associated with increased odds of alcohol (OR=1.3; 95% CI=1.2-1.4) and nicotine (OR=1.2; 95% CI=1.1-1.3) dependence. Similarly, any traumatic event exposure was associated with increased odds of alcohol (OR=3.1; 95% CI=1.6-6.0) and nicotine (OR=1.9; 95% CI=1.2-2.9) dependence. PTSD symptoms were associated with increased odds of alcohol (OR=1.2; 95% CI=1.1-1.3), nicotine (OR=1.1; 95% CI=1.1-1.2), and marijuana (OR=1.1; 95% CI=1.04-1.2) dependence; similarly, a PTSD diagnosis was associated with increased odds of alcohol (OR=3.4; 95% CI=2.1-5.5), nicotine (OR=2.2; 95% CI=1.4-3.4), and marijuana (OR=2.6; 95% CI=1.2-5.9) dependence. PTSD symptoms accounted for a sizeable proportion of the TE effect on alcohol (46%) and nicotine dependence (31%). CONCLUSION: Individuals with more traumatic events had heightened risk for alcohol and nicotine dependence, and PTSD symptoms partially accounted for this risk. However, marijuana dependence was only significantly related to PTSD symptoms. Clinicians and researchers should separately assess different types of dependence among trauma-exposed individuals both with and without PTSD symptoms.

Exposure to the Lebanon War of 2006 and effects on alcohol use disorders: the moderating role of childhood maltreatment.

BACKGROUND: Civilian populations now comprise the majority of casualties in modern warfare, but effects of war exposure on alcohol disorders in the general population are largely unexplored. Accumulating literature indicates that adverse experiences early in life sensitize individuals to increased alcohol problems after adult stressful experiences. However, child and adult stressful experiences can be correlated, limiting interpretation. We examine risk for alcohol disorders among Israelis after the 2006 Lebanon War, a fateful event outside the control of civilian individuals and uncorrelated with childhood experiences. Further, we test whether those with a history of maltreatment are at greater risk for an alcohol use disorder after war exposure compared to those without such a history. METHODS: Adult household residents selected from the Israeli population register were assessed with a psychiatric structured interview; the analyzed sample included 1306 respondents. War measures included self-reported days in an exposed region. RESULTS: Among those with a history of maltreatment, those in a war-exposed region for 30+ days had 5.3 times the odds of subsequent alcohol disorders compared to those exposed 0 days (95%C.I. 1.01-27.76), controlled for relevant confounders; the odds ratio for those without this history was 0.5 (95%C.I. 0.25-1.01); test for interaction: X(2)=5.28, df=1, P=0.02. CONCLUSIONS: Experiencing a fateful stressor outside the control of study participants, civilian exposure to the 2006 Lebanon War, is associated with a heightened the risk of alcohol disorders among those with early adverse childhood experiences. Results suggest that early life experiences may sensitize individuals to adverse health responses later in life.

Biological effects of COMT haplotypes and psychosis risk in 22q11.2 deletion syndrome.

BACKGROUND: 22q11.2 deletion syndrome (22q11.2DS) is the most common genetic syndrome associated with schizophrenia. The catechol-O-methyltransferase (COMT) gene is located in the obligatory deletion region, and possible associations between COMT variants and neuropsychiatric manifestations in 22q11.2DS have been reported. The purpose of the current study was to evaluate the effect of COMT hemizygosity and molecular haplotypes on gene expression and enzyme activity and its association with psychotic symptoms in 22q11.2DS. METHODS: Lymphoblast samples were drawn from 53 individuals with 22q11.2DS and 16 typically developing control subjects. We measured COMT messenger (m)RNA and protein expression and enzyme activity using standard procedures. The presence of a psychotic disorder and cognitive deficits were also evaluated using structured testing. RESULTS: There was an approximately 50% reduction in COMT mRNA, protein, and enzyme activity levels in 22q11.2DS samples. Haplotype analysis revealed clear phenotypic differences between various Val-containing haplotypes on COMT-3' untranslated region extended mRNA, soluble COMT and membrane-bound proteins, and enzyme activity. The G variant of rs165599, a 3' untranslated region single nucleotide polymorphism, was associated with low levels of COMT expression and with the presence of psychosis and lower performance IQ scores in our 22q11.2DS sample. Finally, we demonstrate that the COMT rs74745580 "T" mutation is associated with absent soluble COMT expression and very low COMT activity in two 22q11.2DS individuals. CONCLUSIONS: Our findings confirm a robust effect of COMT hemizygosity on COMT activity and show complex interactions of variants within the COMT gene that influence COMT biology and confound conclusions based on associations with the Val158Met genotype alone.

Risk factors and the evolution of psychosis in 22q11.2 deletion syndrome: a longitudinal 2-site study.

OBJECTIVE: 22q11.2 Deletion syndrome (22q11.2DS) is associated with high rates of schizophrenia, other neuropsychiatric disorders, and cognitive deficits. The objectives of this 2-center study were to longitudinally assess the trajectories of psychiatric disorders in 22q11.2DS from childhood to adulthood, and to identify risk factors for their emergence. METHOD: A total of 125 children and adults with 22q11.2DS were evaluated at 2 time points, baseline and follow-up (4 years apart), using standardized psychiatric and cognitive measures. RESULTS: The rate of mood disorders tended to decrease during childhood and increase during late adolescence. Statistically significant predictors for the presence of a psychotic disorder as well as the severity of positive symptoms at follow-up were identical, and consisted of an anxiety disorder at baseline, lower baseline Full Scale IQ, and a greater decrease in verbal IQ scores between time points. Nine of 10 individuals with an emerging psychotic disorder had an anxiety disorder at baseline. The age of onset for a psychotic disorder was between 14 and 22 years in 82.6% of cases. CONCLUSIONS: It is important to evaluate the presence of anxiety disorders in children and adolescents with 22q11.2DS, as they are major risk factors for the emergence of psychotic disorders, which usually occur during late adolescence in this at-risk population.

Schizophrenia-like neurophysiological abnormalities in 22q11.2 deletion syndrome and their association to COMT and PRODH genotypes.

22q11.2 deletion syndrome (22q11.2DS) is a common genetic risk factor for the development of schizophrenia. We investigated two neurophysiological endophenotypes of schizophrenia - P50 sensory gating and mismatch negativity in 22q11.2DS subject and evaluated their association with catechol O-methyltransferase (COMT) and proline dehydrogenase (PRODH) genetic variants. We also assessed the association of neurophysiological measures with schizophrenia-like symptomatology in 22q11.2DS. Fifty-nine subjects, 41 with 22q11.2DS and 18 typically developing controls, participated in the study. The participants with 22q11.2DS were genotyped for the COMT Val(158)Met (rs4680) and PRODH Gln(19)Pro (rs2008720) and Arg(185)Trp (rs4819756) polymorphisms. Following psychiatric evaluation, all the participants underwent neurophysiological recordings and executive function assessment. The 22q11.2DS group showed poorer sensory gating of the P50 response than the controls. Within the 22q11.2DS group, the COMT Met allele was associated with poorer sensory gating, while both the COMT Met allele and the PRODH Pro-Arg haplotype were associated with smaller mismatch negativity amplitudes. Smaller mismatch negativity amplitudes predicted greater impairment of executive functions and greater severity of schizophrenia-like negative symptoms in 22q11.2DS. The current study demonstrates that sensory gating impairments that are typical of schizophrenia are found in 22q11.2DS subjects. Our results further suggest that COMT and PRODH genetic variations contribute to sensory gating and mismatch negativity schizophrenia-like impairments in 22q11.2DS, possibly via dopaminergic/glutamatergic networks. The associations of mismatch negativity impairments with increased severity of schizophrenia-like negative symptoms and poorer executive functions performance in our 22q11.2DS sample suggest that mismatch negativity is a potential endophenotype for schizophrenia in 22q11.2DS.