Biomedical subjects

Amos Frisch

Publications and source records attributed to Amos Frisch.

16 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

Obsessive-compulsive disorder in patients with velocardiofacial (22q11 deletion) syndrome.

The study of neurogenetic microdeletion syndromes provides an insight into the developmental psychopathology of psychiatric disorders. The aim of the study was to evaluate the prevalence of psychiatric disorders, especially obsessive-compulsive disorder (OCD), in patients with velocardiofacial syndrome (VCFS), a 22q11 microdeletion syndrome. Forty-three subjects with VCFS of mean age 18.3 +/- 10.6 years were comprehensively assessed using semi-structured psychiatric interview and the Yale-Brown obsessive compulsive scale (Y-BOCS). Best estimate diagnoses were made on the basis of information gathered from subjects, parents, teachers, and social workers. Fourteen VCFS subjects (32.6%) met the DSM-IV criteria for OCD. OCD had an early age of onset and generally responded to fluoxetine treatment. It was not related to mental retardation. The most common obsessive-compulsive symptoms were contamination, aggression, somatic worries, hoarding, repetitive questions, and cleaning. Sixteen of the 43 patients (37.2%) had attention-deficit/hyperactivity disorder (ADHD), and 7 (16.2%) had psychotic disorder. The results of our study suggest that there is a strong association between VCFS and early-onset OCD. This finding may be significant in the understanding of the underlying genetic basis of OCD.

Adolescent↗

PubMed2004

Genetic, developmental, and physical factors associated with attention deficit hyperactivity disorder in patients with velocardiofacial syndrome.

Velocardiofacial syndrome (VCFS) is a relatively common developmental neuropsychiatric syndrome caused by a 22q11 microdeletion. There is an extensive variability in the phenotypic expression of this disease. The most common psychiatric disorder in VCFS is attention-deficit/hyperactivity disorder (ADHD), affecting 35-55% of patients. This study investigated the association of familial, developmental, and physical factors with the occurrence of ADHD in 51 patients with nonfamilial VCFS. Twenty-one patients (41.2%) were diagnosed with ADHD. There was a significantly greater prevalence of ADHD in the first-degree relatives of the patients with ADHD than in those without (OR = 5.9, 95% CI = 1.6-22.1, P = 0.006). No differences were noted between the ADHD and non-ADHD groups in mean Obstetric Complication Scale Score, gestational age, birth weight, age at first words, walking, and achieving bowel control. The two groups also had similar IQ scores (total, verbal, and performance) and had a similar average degree of severity of facial dysmorphism and cardiac and cleft anomalies. These findings indicate that ADHD in VCFS has a genetic contribution and the patients' VCFS-related developmental factors and physical illnesses play a lesser role.

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

Specific mutations in the HEXA gene among Iraqi Jewish Tay-Sachs disease carriers: dating of founder ancestor.

The incidence of Tay-Sachs disease (TSD) carriers, as defined by enzyme assay, is 1:29 among Ashkenazi Jews and 1:110 among Moroccan Jews. An elevated carrier frequency of 1:140 was also observed in the Iraqi Jews (IJ), while in other Israeli populations the world's pan-ethnic frequency of approximately 1:280 has been found. Recently a novel mutation, G749T, has been reported in 38.7% of the IJ carriers (24/62). Here we report a second novel HEXA mutation specific to the IJ TDS carriers: a substitution of cytosine 1351 by guanosine (C1351G), resulting in the change of leucine to valine in position 451. This mutation was found in 33.9% (21/62) of the carriers and in none of 100 non-carrier IJ. In addition to the two specific mutations, 14.5% (9/62) of the IJ carriers bear a known "Jewish" mutation (Ashkenazi or Moroccan) and 11.3% (7/62) carry a known "non-Jewish" mutation. In 1 DNA sample no mutation has yet been detected. To investigate the genetic history of the IJ-specific mutations (C1351G and G749T), the allelic distribution of four polymorphic markers (D15S131, D15S1025, D15S981, D15S1050) was analyzed in IJ heterozygotes and ethnically matched controls. Based on linkage disequilibrium, recombination factor (theta) between the markers and mutated loci, and the population growth correction, we deduced that G749T occurred in a founder ancestor 44.8 +/- 14.2 generations (g) ago [95% confidence interval (CI) 17.0-72.6 g] and C1351G arose 80.4 +/- 35.9 g ago (95% CI 44.5-116.3 g). Thus, the estimated dates for introduction of mutations are: 626 +/- 426 A.D. (200-1052 A.D.) for G749T and 442 +/- 1077 B.C. (1519 B.C. to 635 A.D.) for C1351G.

Founder Effect↗

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↗

PubMed2003

Methylphenidate treatment for attention-deficit/hyperactivity disorder in children and adolescents with velocardiofacial syndrome: an open-label study.

BACKGROUND: Velocardiofacial syndrome (VCFS) is a common microdeletion syndrome associated with psychiatric morbidity and developmental disabilities. Although attention-deficit/hyperactivity disorder (ADHD) is the most common psychiatric problem associated with VCFS, there are no reports on methylphenidate treatment in this patient population. Indeed, clinicians have commonly avoided the use of methylphenidate in children with VCFS because of concerns about ineffectiveness or psychotic exacerbation. METHOD: Forty subjects of mean +/- SD age 11.0 +/- 5.0 years with VCFS were assessed for DSM-IV diagnoses using the Schedule for Affective Disorders and Schizophrenia for School-Aged Children, Present and Lifetime Version, and its extended ADHD module (K-SADS-P-ADHD). Those found to have comorbid ADHD were treated with methylphenidate, 0.3 mg/kg once daily. Treatment efficacy was evaluated after 4 weeks with the K-SADS-P-ADHD, the Conners' Abbreviated Teacher Questionnaire, and the Conners' Continuous Performance Test. Side effects were evaluated with a modified version of the Barkley Side Effects Rating Scale. RESULTS: Of the 18 subjects (45%) diagnosed with ADHD, 12 agreed to participate in the study. Their ADHD symptoms, both behavioral and cognitive, improved significantly with treatment. None of the patients showed clinical worsening or psychotic symptoms. Side effects were usually mild and did not warrant discontinuation of methylphenidate. The most common side effects were anorexia and depressive-like symptoms. CONCLUSION: This open-label study indicates that methylphenidate is effective and safe in patients with VCFS. Therefore, its current limited use in this population seems to be unjustified. Larger, controlled clinical and pharmacogenetic studies are needed to confirm these findings.

Adolescent↗

PubMed2002

Association of tetralogy of Fallot with a distinct region of del22q11.2.

Congenital heart defects (CHDs) appear in greater frequency among relatives of patients and in individuals with DiGeorge syndrome (DGS) or velo-cardio-facial syndrome (VCFS). A majority of these patients and part of the apparently nonsyndromic CHD patients with conotruncal defects manifest hemizygous deletions within chromosome 22q11.2 (del22q11). We tested myocardial tissues of 31 CHD patients, 21 with tetralogy of Fallot (TOF) and 10 with a double-chamber right ventricle (DCRV). DNA isolated from tissues removed at corrective surgery was analyzed for homo- or heterozygosity of nine polymorphic short tandem repeat (STR) markers along the 22q11.2 region. DNA from the blood of 45 healthy individuals represented the general population. Ten of the 21 TOF patients (48%) showed homozygosity for three or more consecutive markers, indicating deletions of various sizes. No such indication was found for DCRV patients. Heterozygosity for markers D22S1648, D22S941, and D22S944 was lower in the TOF group than in normal controls, defining a minimal critical region (MCR) for the deletion. Our findings support an association between TOF and hemizygosity in 22q11.2, suggesting a distinct region, between markers D22S1638 and COMT, that may harbor TOF susceptibility genes.

Adult↗

PubMed2002

Genetics of suicidal behavior: candidate association genetic approach.

Suicidal behavior runs in families and seemed to be genetically determined in part and independent of the presence of psychiatric disorders. This review presents the current knowledge of candidate gene association studies in the field of suicidology. Concordance for monozygotic twins is about 13% Vs. 0.7% in dizygotics. It seems that there is a relationship to intermediate phenotypes such as impulsivity and aggression. The problem of studying complex traits and of ethnic stratification in heterogeneous population are major concerns in studying genetics of suicide. Family-based methods is one of the strategies to overcome stratification. We found a possible association of tryptophane hydroxylase gene polymorphism with depression and serotonin transporter promoter gene to violence traits by family-based methods. Recent data from the study of COMT. MAO and serotonin receptors genes polymorphisms are controversial at this stage. Future directions for research includes alternative phenotypes, endo-phenotypes and genome scan.

Adolescent↗

PubMed2002

Heritability, genetics and association findings in anorexia nervosa.

Anorexia nervosa (AN) is a severe psychiatric disorder, characterized by a combination of abnormal eating behavior and weight regulation with disturbances of attitudes toward body weight and shape. Prevalence is estimated at 1/1000, but with a high prevalence of the partial syndrome and a 10% mortality rate. This article reviews the findings concerning the heritability and the contributing genes of the disorder, with a focus on candidate genes. In family studies, a higher frequency of AN and BN was found among relatives of AN probands. The heritability rate was estimated at 0.71, similar to twin studies, which estimate 0.58-0.76. The search for genes responsible for the disorder focuses on the monoaminergic and peptidergic systems that are related to appetite and weight regulation. So far, for serotonin and dopamine there are no consistent findings in association studies of AN. However, in an Israeli study, an association was found between susceptibility for AN and the COMT gene, which is involved in monoamine metabolism. Another Israeli study found a relation between AN and the gene encoding for the potassium channel (hSKCa3), which is involved in regulation of neuronal activity. In the endocrine system an unequivocal finding was described of an association to the gene encoding the receptor for beta-estrogen. In the appetite and weight regulation system an association was described between AN and a marker of the uncoupling protein-2 and -3 chromosomal region, raising the likelihood that the mutation within the gene is close to a positive marker. To conclude, although there is a strong familial component in AN, so far the search for candidate genes has not been fruitful and further large scale prospective and adoption studies are needed to confirm genetic factors. We hope that relative studies using a wide genome scan, as well as subtyping the different types of AN, will bring us closer to understanding of the heritability of AN and enable the development of improved means of prevention and treatment.

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↗