Biomedical subjects

Elena Michaelovsky

Publications and source records attributed to Elena Michaelovsky.

9 recordsLinked to original sources

PubMed2006

Association of the serotonin transporter promotor polymorphism with suicide attempters with a high medical damage.

Serotonergic neurotransmission has been implicated in suicidal behavior, including inconsistent results concerning the serotonin transporter promoter polymorphism (5-HTTLPR). Here, we analyzed the 5-HTTLPR in suicide attempters (n=85). Comparing the presence of SS with SL+LL genotypes showed a significantly higher prevalence of the SS genotype in suicide attempters with high medical damage scores (chi2=9.054, df=1, p=0.0026). The results suggest that the S-allele may predispose for suicidal behavior characterized by high determination.

Adult↗

PubMed2006

Association of the low-activity COMT 158Met allele with ADHD and OCD in subjects with velocardiofacial syndrome.

Velocardiofacial syndrome (VCFS) is caused by a microdeletion in chromosome 22 and is a risk factor for the development of schizophrenia and other psychiatric disorders. The catechol-O-methyltransferase (COMT), residing in the 22q11.2 microdeletion region, is a major candidate gene for genetic susceptibility to neuropsychiatric disorders in VCFS. Individuals with VCFS carrying the low-activity allele (COMTL) are expected to have the lowest possible COMT activity since they have only a single copy of the gene. We explored the possibility that COMTL is associated with psychiatric disorders commonly found in VCFS. Fifty-five unrelated individuals with VCFS underwent psychiatric evaluation and were genotyped for the COMT 158Val/Met polymorphism coding for COMT high/low-activity alleles. The COMTL allele was significantly more prevalent in VCFS subjects with attention deficit hyperactivity disorder (ADHD) (73.9% vs. 33.3%, OR 5.67, chi2=7.76, p=0.005) and obsessive-compulsive disorder (OCD) (78.6% vs. 33.3%, OR 7.33, chi2=7.24, p=0.007) than in the control group (VCFS subjects without OCD, ADHD and schizophrenia/schizoaffective (SZ/SZaff) disorder). The results of this study suggest that greatly reduced COMT activity, as expected in VCFS COMTL individuals may be a risk factor for psychiatric sequelae in this population. Future longitudinal studies focusing on additional COMT polymorphic sites and other candidate genes from the deleted region will elucidate the molecular pathways leading to schizophrenia and other psychiatric disorders in VCFS.

Adolescent↗

PubMed2005

COMT Val158Met polymorphism in schizophrenia with obsessive-compulsive disorder: a case-control study.

This is the first study of a possible molecular genetic basis for schizophrenia with obsessive-compulsive disorder (OCD). We performed a case-control association study of the catechol-O-methyltransferase (COMT) Val158Met polymorphism in schizophrenia-OCD patients, OCD and healthy controls. One hundred and thirteen schizophrenia-OCD patients, 79 OCD patients and 171 control subjects were genotyped for the Val(158)Met polymorphism in the COMT gene. There was no significant difference in allele and genotype distribution of the COMT gene between schizophrenia-OCD patients and healthy controls. The low-activity Met allele and Met/Met genotype were more frequent in OCD men than in schizophrenia-OCD and control individuals. This difference, however, was not statistically significant following correction for multiple comparisons. These results do not support the hypothesis that the COMT Val158Met gene polymorphism is associated with liability to schizophrenia-OCD.

Case-Control Studies↗

PubMed2005

Haplotype analysis of the COMT-ARVCF gene region in Israeli anorexia nervosa family trios.

Anorexia nervosa (AN) is a severe and complex psychiatric disorder with a significant genetic contribution. Previously, we found an association between AN and the 158Val/Met polymorphism of the catechol-O-methyltransferase (COMT) gene in a family-based study of 51 Israeli AN trios. In the present study, we extended the original sample to include 85 family trios [66 AN restricting (AN-R) and 19 bingeing/purging (AN-BP) subtype] and performed a family-based transmission disequilibrium test (TDT) analysis for five SNPs in the COMT and two in the adjacent ARVCF gene. Association was found between AN-R and several SNPs in the COMT-ARVCF region including the 158Val/Met polymorphism. TDT analysis of 5-SNP haplotypes in AN-R trios revealed an overall statistically significant transmission disequilibrium (P < 0.001). Specifically, haplotype B [COMT-186C-408G-472G(158Val)-ARVCF-659C(220Pro)-524T(175Val)] was preferentially transmitted (P < 0.001) from parents of AN-R patients to their affected daughters, while haplotype A [COMT-186T-408C-472A(158Met)-ARVCF-659T(220Leu)-524C(175Ala)] was preferentially (P = 0.01) not transmitted. Haplotype B was associated with increased risk (RR 3.38; 0.95CI 1.98-6.43) while haplotype A exhibited a protective effect (RR 0.40; 0.95CI 0.21-0.70) for AN-R. Preferential transmission of the risk alleles and haplotypes from the parents was mostly contributed by the fathers. No significant transmission disequilibrium of alleles or haplotypes was found for AN-BP trios. The risk and protective haplotypes may carry molecular variations in the COMT gene or its vicinity that are relevant to the pathophysiology of restrictive anorexia nervosa in the Israeli-Jewish population.

Adolescent↗

PubMed2005

Dual contribution of NR2B subunit of NMDA receptor and SK3 Ca(2+)-activated K+ channel to genetic predisposition to anorexia nervosa.

Since identification of the genetic component in anorexia nervosa (AN), genes that partake in serotonergic and dopaminergic systems and in hormonal and weight regulation have been suggested as potential candidates for AN susceptibility. We propose another set of candidate genes. Those are genes that are involved in the signaling pathway using NMDA-R and SK channels and have been suggested as possible effectors of NMDA-R driven signaling. The role of NMDA-R in the etiology of schizophrenia has already been substantiated on various levels. Several studies based on population and family groups have implicated SK3 in schizophrenia and more recently in AN as well. Our study group consisted of 90 AN family trios. We examined the transmission of two potentially functional polymorphisms, 5073T>G polymorphism in the gene encoding the NR2B subunit of NMDA-R and CAG repeats in the coding region of SK3 channel gene. Using HHRR and TDT approaches, we found that both polymorphisms were preferentially transmitted to AN offspring (TDT yielded chi(2)=5.01, p=0.025 for NR2B 5073G alleles and chi(2)=11.75, p<0.001 for SK3 L alleles including >19 repeats). Distribution analysis of the combined NR2B/SK3 genotypes suggests that the contribution of both polymorphisms to AN risk is independent and cumulative (OR=2.44 for NR2B GG genotype and OR=3.01 for SK3 SL and LL genotypes, and OR=6.8 for the combined NR2B/SK3 genotypes including high-risk alleles). These findings point to the contribution of genes associated with the NMDA-R signaling pathway to predisposition and development of AN.

Adolescent↗

PubMed2004

CAG repeat polymorphism within the KCNN3 gene is a significant contributor to susceptibility to anorexia nervosa: a case-control study of female patients and several ethnic groups in the Israeli Jewish population.

The human small-conductance Ca(2+)-activated potassium channel gene KCNN3 has been involved in mechanisms underlying neuronal function and plasticity. A multiallelic CAG repeat polymorphism within the KCNN3 has been associated with schizophrenia and bipolar disorder. We have previously reported in a family-based study that longer CAG repeats are preferentially transmitted to patients with anorexia nervosa (AN). The present study extends the analysis of KCNN3 allele distribution to a larger series of AN female patients and control groups, incorporating information on ethnicity and co-morbidities associated with AN. The data analysis is presented while considering separately the two alleles of each individual, namely a minor (shorter) and a major (longer) allele. This study has found that the KCNN3 allele distribution in the general Israeli population does not differ significantly in at least four Jewish ethnic groups of Ashkenazi, North African, Iraqi, and Yemenite origin. These have been used as control groups in a matched case-control analysis that has demonstrated a significant over-representation of KCNN3 alleles with longer CAG repeats among AN patients (P < 0.001 for the major allele and P = 0.035 for allele sum). Under dichotomization, a significantly higher prevalence of the L allele (>19 repeats) has been observed among AN patients (P < 0.001). While considering AN and co-morbid phenotypes, a tendency towards longer (L) alleles has been observed in the subset of patients with obsessive-compulsive disorder (OCD) co-morbidity. These findings further implicate KCNN3 as a significant contributor to predisposition to AN.

Adolescent↗

PubMed2004

Origin and spread of the 1278insTATC mutation causing Tay-Sachs disease in Ashkenazi Jews: genetic drift as a robust and parsimonious hypothesis.

The 1278insTATC is the most prevalent beta-hexosaminidase A ( HEXA) gene mutation causing Tay-Sachs disease (TSD), one of the four lysosomal storage diseases (LSDs) occurring at elevated frequencies among Ashkenazi Jews (AJs). To investigate the genetic history of this mutation in the AJ population, a conserved haplotype (D15S981:175-D15S131:240-D15S1050:284-D15S197:144-D15S188:418) was identified in 1278insTATC chromosomes from 55 unrelated AJ individuals (15 homozygotes and 40 heterozygotes for the TSD mutation), suggesting the occurrence of a common founder. When two methods were used for analysis of linkage disequilibrium (LD) between flanking polymorphic markers and the disease locus and for the study of the decay of LD over time, the estimated age of the insertion was found to be 40+/-12 generations (95% confidence interval: 30-50 generations), so that the most recent common ancestor of the mutation-bearing chromosomes would date to the 8th-9th century. This corresponds with the demographic expansion of AJs in central Europe, following the founding of the Ashkenaz settlement in the early Middle Ages. The results are consistent with the geographic distribution of the main TSD mutation, 1278insTATC being more common in central Europe, and with the coalescent times of mutations causing two other LSDs, Gaucher disease and mucolipidosis type IV. Evidence for the absence of a determinant positive selection (heterozygote advantage) over the mutation is provided by a comparison between the estimated age of 1278insTATC and the probability of the current AJ frequency of the mutant allele as a function of its age, calculated by use of a branching-process model. Therefore, the founder effect in a rapidly expanding population arising from a bottleneck provides a robust parsimonious hypothesis explaining the spread of 1278insTATC-linked TSD in AJ individuals.

Alleles↗

PubMed2003

DRD4 exon III polymorphism and response to risperidone in Israeli adolescents with schizophrenia: a pilot pharmacogenetic study.

This study examined the possible association between the polymorphism in the dopamine receptor DRD4 gene and response to risperidone among 24 Israeli Jewish adolescent inpatients with first-episode schizophrenia. Response was categorically determined by a change of >40% on the Brief Psychiatric Rating Scale (BPRS). No significant association was found between the DRD4 genotype and clinical response, although carriers of <7 repeat alleles demonstrated higher response rate (10/20 vs. 0/4, P=0.11). Studies in larger groups of adolescent schizophrenia patients are warranted to clarify the possible association between DRD4 exon III repeat alleles and the response to risperidone.

Adolescent↗

PubMedDate not supplied

Family-based association study of 5-HT(2A) receptor T102C polymorphism and suicidal behavior in Ashkenazi inpatient adolescents.

UNLABELLED: Suicidal behavior runs in families and is partially genetically determined. Since greater serotonin 5-HT(2A) receptor binding has been reported in postmortem brain and platelets of suicide victims, the 5-HT(2A) receptor gene polymorphism T102C became one of the candidate sites in the study of suicide and impulsive-aggressive traits. However, studies that examined the association of this polymorphism with suicidality have contradictory results. This study used a family-based method and one homogenous ethnic group to overcome ethnic stratification in order to test this association. METHODS: Thirty families of inpatient adolescents from Jewish Ashkenazi origin, with a recent suicide attempt, were genotyped. All subjects were interviewed for clinical diagnosis, depressive and impulsive-aggressive traits and demographic data. Allele frequencies were assessed using the Haplotype Relative Risk method for trios. RESULTS: No difference was found in allelic distribution between transmitted and non-transmitted alleles. There was no significant association of genotype with any of the clinical traits CONCLUSIONS: These preliminary results suggest that the 5-HT(2A) T102C polymorphism is unlikely to be associated with suicidal behavior and related traits in adolescent suicide attempters.

Adolescent↗