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M Rietschel

Publications and source records attributed to M Rietschel.

At least 37 records · Page 2Linked to original sources
PubMed2001

A genome screen for genes predisposing to bipolar affective disorder detects a new susceptibility locus on 8q.

Bipolar affective disorder (BPAD), also known as manic depressive illness, is a severe psychiatric disorder characterized by episodes of mania and depression. It has a lifetime prevalence of approximately 1% in all human populations. In order to identify chromosomal regions containing genes that play a role in determining susceptibility to this psychiatric condition, we have conducted a complete genome screen with 382 markers (average marker spacing of 9.3 cM) in a sample of 75 BPAD families which were recruited through an explicit ascertainment scheme. Pedigrees were of German, Israeli and Italian origin, respectively. Parametric and non-parametric linkage analysis was performed. The highest two-point LOD score was obtained on 8q24 (D8S514; LOD score = 3.62), in a region that has not attracted much attention in previous linkage studies of BPAD. The second best finding was seen on 10q25-q26 (D10S217; LOD score = 2.86) and has been reported in independent studies of BPAD. Other regions showing 'suggestive' evidence for linkage localized to 1p33-p36, 2q21-q33, 3p14, 3q26-q27, 6q21-q22, 8p21, 13q11 and 14q12-q13. In addition, we aimed at detecting possible susceptibility loci underlying genomic imprinting by analyzing the autosomal genotype data with the recently developed extension of the GENEHUNTER program, GENEHUNTER-IMPRINTING. Putative paternally imprinted loci were identified in chromosomal regions 2p24-p21 and 2q31-q32. Maternally imprinted susceptibility genes may be located on 14q32 and 16q21-q23.

Bipolar Disorder↗
PubMed2001

Lack of association between a functional polymorphism of the cytochrome P450 1A2 (CYP1A2) gene and tardive dyskinesia in schizophrenia.

Tardive dyskinesia (TD) is a common side effect of long-term medication with typical neuroleptics. TD presents itself by abnormal involuntary movements and may lead to a potentially disabling and chronic clinical course. A vast majority of patients suffering from schizophrenia are smokers. Smoking has been reported to induce the activity of the CYP1A2 enzyme, which is an established metabolic pathway within the disposition of antipsychotics. Recently, a C-->A genetic polymorphism in the first intron of the CYP1A2 gene was reported to influence CYP1A2 activity in smokers. Subsequently, a pharmacogenetic study in 85 U.S. patients with schizophrenia (44 smokers, 41 individuals with unknown smoking status) showed the C/C genotype to be associated with higher TD severity (measured by the Abnormal Involuntary Movement Scale, AIMS) than the A/C or A/A genotype. This finding prompted us to investigate whether this effect was also present in a larger German sample of 119 patients with schizophrenia (82 smokers, 37 individuals with unknown smoking status). However, we could not replicate the reported association. The median AIMS scores did not differ between individuals with the A/A, A/C, or C/C genotypes. In an additional analysis, we compared the genotypic and allelic distribution among individuals grouped according to the criteria established by Schooler and Kane [1982: Arch Gen Psychiatry 39:486-487] (persistent TD vs. absent TD). We did not observe a differential genotypic or allelic distribution between the two diagnostic groups. Thus, our results do not support the hypothesis that the C-->A polymorphism in the CYP1A2 gene is involved in the etiology of TD in the German population.

Adult↗
PubMed2001

No evidence for linkage by transmission disequilibrium test analysis of microsatellite marker D22S278 and schizophrenia in a Palestinian Arab and in a German population.

Linkage for a schizophrenia susceptibility locus on chromosome region 22q12-q13 was initially suggested by independent studies from two groups and confirmed in a combined analysis of data for the microsatellite marker D22S278 in multiply affected schizophrenic families derived from 11 independent research groups worldwide. In addition to these reports of linkage to schizophrenia on chromosome 22, bipolar disorder has also been linked to markers in this chromosomal region. We now report results from an analysis of 223 Palestinian Arab trios from three different centers in Israel and Palestine using the allele-wise extended transmission disequilibrium test for multiallelic markers. No evidence for linkage is observed in the entire group or in any of the three centers (entire group: chi-square = 5.59, P = 0.78, df = 9; Afula: chi-square = 6.51, P = 0.48, df = 7; Bethlehem: chi-square = 14.11, P = 0.12, df = 9; Beersheva: chi-square = 7.04, P = 0.32, df = 6). Additionally, we examined D22S278 in a group of 114 schizophrenic German triads and failed to observe evidence for linkage (chi-square = 8.13, P = 0.42, df = 8df).

Alleles↗
PubMed2001

Caught in the trio trap? Potential selection bias inherent to association studies using parent-offspring trios.

During the last years, the validity of classic case control studies in psychiatric genetic research has been increasingly under question due to the risk of population stratification problems inherent to this type of association study. By consequence, the application of family-based association studies using parent-offspring trios has been strongly advocated. Recently, however, in a study comparing clinical characteristics between index patients from parent-offspring trios and singleton patients with bipolar affective disorder, the question was raised whether a systematic neglect of case control association studies could lead to a selection bias of susceptibility genes. In a similar approach, we compared demographic and clinical characteristics of 122 singleton bipolar patients with those of 54 bipolar patients derived from parent-offspring trios. The singleton patients did not only present with a higher age of onset, but also with a higher frequency of suicidal behavior and a higher familial loading for suicidality. These findings suggest that the genetic mechanism for disease might be different between trio-based and classic case control samples, where patients are examined whose parents are not available for genetic studies. Thus, giving up case control designs for the sake of family-based association studies could be at the risk of selecting against several genetically determined factors.

Adult↗
PubMed2001

A family-based study of the Cys23Ser 5HT2C serotonin receptor polymorphism in schizophrenia.

The 5HT2C receptor has a high affinity for clozapine, a nontypical neuroleptic, and has therefore been postulated to play a role in mediating negative symptoms and neuroleptic response in schizophrenia. In the current study, the Cys23Ser 5HT2C serotonin receptor polymorphism was examined for linkage to schizophrenia by genotyping 207 nuclear families consisting of both parents and schizophrenic child and using the transmission disequilibrium test to examine possible preferential transmission of these alleles from 68 heterozygous mothers to their ill child. No evidence was obtained for preferential transmission of the Cys23Ser 5HT2C alleles in schizophrenia in either of the two main ethnic groups examined (German and Palestinian Arab) or in the combined cohort (TDT chi-square = 0.00, NS).

Adolescent↗
PubMed2001

Major psychoses symptomatology: factor analysis of 2241 psychotic subjects.

Current nosography classifies major psychoses as separate disorders, but their symptomatological presentation during illness episodes largely overlaps and diagnoses may change during a lifetime. Few analyses of major psychoses symptomatology have been performed so far because of the large number of subjects needed to obtain stable factors. The purpose of this study was, therefore, to identify the symptomatologic structure common to major psychoses based on lifetime symptoms. Two thousand and forty-one inpatients affected by schizophrenic (n=1008), bipolar (n=563), major depressive (n=352), delusional (n=108) and psychotic not otherwise specified disorder (n=210) were rated for lifetime symptoms using the Operational Criteria Checklist for Psychotic Illness (OPCRIT) and included in a factorial analysis. Four factors were obtained, the first consisted of excitement symptoms, the second comprised psychotic features (delusions and hallucinations), the third comprised depression and the fourth disorganization. When scored by the OPCRIT checklist, major psychoses symptomatology is composed of excitement, depressive, delusion and disorganization symptoms.

Adult↗
PubMed2001

Affective symptomatology in schizophrenia: a risk factor for tardive dyskinesia?

Affective symptomatology has repeatedly been suggested to confer susceptibility to tardive dyskinesia (TD). In our sample of 174 schizophrenic patients a history of depressive symptoms was not associated with the occurrence of TD, whereas manic symptomatology was significantly associated with the absence of TD. Thus, our data suggest that affective symptomatology cannot unambiguously be considered to predispose to TD.

Adult↗
PubMed2001

Familial occurrence of tardive dyskinesia.

OBJECTIVE: Familial occurrence of tardive dyskinesia (TD) and schizophrenia has been hypothesized to confer risk to the development of TD. We investigated these hypotheses in a large patient sample applying standardized methods for phenotype characterization. METHOD: Two hundred and twenty-two patients with a diagnosis of schizophrenia or schizoaffective disorder were assessed for TD and for family history of schizophrenia or schizoaffective disorder. Thirty-nine patients had 40 affected first-degree family members, one patient having two first-degree relatives. Of these, 17 pairs and one triplet were personally examined. RESULTS: 1) There was a tendency for TD in the affected relatives to be associated with the TD status of the index-patient; this finding was unrelated to age and doses of neuroleptic medication. 2) No association between a family history of schizophrenia or schizoaffective disorder and TD was found. CONCLUSION: A family history of TD might represent a risk factor for TD, whereas a family history of schizophrenia does not.

Adult↗
PubMed2001

A possible susceptibility locus for bipolar affective disorder in chromosomal region 10q25--q26.

In an attempt to identify susceptibility loci for bipolar affective disorder, we are currently conducting a systematic genome screen with highly polymorphic microsatellite markers at an average marker spacing of 10 cM in a series of 75 families, comprising 66 families from Germany, eight families from Israel, and one family from Italy. The families were ascertained through index cases with bipolar affective disorder. The distribution of diagnoses is as follows: 126 individuals with bipolar I disorder, 40 with bipolar II disorder, 14 with schizoaffective disorder of the bipolar type, 40 individuals with recurrent unipolar depression, 51 with a minor psychiatric diagnosis, and two individuals with a diagnosis of schizophrenia. One hundred and seventy-one individuals are unaffected. Here, we present results from chromosome 10. Linkage analyses using a total of 33 microsatellite markers with parametric and non-parametric methods provided evidence for linkage at chromosomal region 10q25--q26. The highest two-point LOD score (2.86, theta = 0.05) was obtained for D10S217 using a dominant genetic model and a broad definition of affection status. The GENEHUNTER program localized the putative susceptibility locus within a ca 15-cM interval between markers D10S1483 and D10S217 with a maximum NPL(all) score of 3.12 (P = 0.0013). Positive linkage findings that have been reported by two independent studies further support the hypothesis of a susceptibility gene for bipolar affective disorder on 10q25-q26.

Bipolar Disorder↗
PubMed2001

Variability of 5-HT2C receptor cys23ser polymorphism among European populations and vulnerability to affective disorder.

Substantial evidence supports a role for dysfunction of brain serotonergic (5-HT) systems in the pathogenesis of major affective disorder, both unipolar (recurrent major depression) and bipolar.(1) Modification of serotonergic neurotransmission is pivotally implicated in the mechanism of action of antidepressant drugs(2) and also in the action of mood stabilizing agents, particularly lithium carbonate.(3) Accordingly, genes that code for the multiple subtypes of serotonin receptors that have been cloned and are expressed in brain,(4) are strong candidates for a role in the genetic etiology of affective illness. We examined a structural variant of the serotonin 2C (5-HT2C) receptor gene (HTR2C) that gives rise to a cysteine to serine substitution in the N terminal extracellular domain of the receptor protein (cys23ser),(5) in 513 patients with recurrent major depression (MDD-R), 649 patients with bipolar (BP) affective disorder and 901 normal controls. The subjects were drawn from nine European countries participating in the European Collaborative Project on Affective Disorders. There was significant variation in the frequency of the HT2CR ser23 allele among the 10 population groups included in the sample (from 24.6% in Greek control subjects to 9.2% in Scots, chi(2) = 20.9, df 9, P = 0.01). Logistic regression analysis demonstrated that over and above this inter-population variability, there was a significant excess of HT2CR ser23 allele carriers in patients compared to normal controls that was demonstrable for both the MDD (chi(2) = 7.34, df 1, P = 0.006) and BP (chi(2) = 5.45, df 1, P = 0.02) patients. These findings support a possible role for genetically based structural variation in 5-HT2C receptors in the pathogenesis of major affective disorder.

Amino Acid Substitution↗
PubMed2001

[Pharmacogenetic strategies].

Factors influencing treatment outcome to medication include previous history of response to medication, duration of illness, ethnicity, and gender; as well as genetic factors. These genetic factors influence pharmacokinetic and pharmacodynamic effects of specific drugs such as absorption, metabolism, elimination, transport across the blood-brain barrier, and drug-target interactions. The detection of individual genetic differences in response to medication may lead to important new strategies for the treatment of psychiatric disorders. With the advent of molecular biology individual differences can be determined on the molecular level. The awareness of the importance of pharmacogenetic factors has recently led to numerous studies seeking association between genetic variants and treatment-outcome. The results however, are partially inconsistent. One of the main reasons for this inconsistency may be accounted by heterogeneity of study designs. As in genetic studies of complex phenotypes, several replications are required before a result can be accepted, first 'guidelines' have been proposed to make those studies comparable. These 'guidelines' and study results will be presented.

Antipsychotic Agents↗
PubMed2001

Serotonin receptor gene HTR3A variants in schizophrenic and bipolar affective patients.

Serotonin receptor genes have always been considered excellent candidate genes in the aetiology of neurogenetic diseases. In this study, we assessed sequence variations of the HTR3A gene. For this purpose, we established exon-specific primers and analysed DNA samples from 165 unrelated individuals including 70 schizophrenic patients, 48 patients with bipolar affective disorder and 47 healthy control persons using polymerase chain reaction/single-strand conformational polymorphism analysis. We discovered six sequence variants, five of which represent polymorphisms. These polymorphisms could not be associated with schizophrenia and bipolar affective disorder (P = 0.055-1). We also detected a missense mutation in exon 9 in a schizophrenic patient at a conserved position (Pro391Arg). To determine the incidence of this substitution an extended set of 358 schizophrenic patients and 155 control individuals was investigated. The Pro391Arg mutation was not detected in these schizophrenic patients and controls screened. However, a second missense mutation (Arg344His) was detected in one schizophrenic patient, but not in any of the controls. These results suggest that the observed mutations in HTR3A are rare and therefore do not play a major role in the aetiology of the disorder. Further studies are needed to support the hypothesis that HTR3A may contribute to the schizophrenia in these patients.

Adult↗
PubMed2001

Association between the 5' UTR variant C178T of the serotonin receptor gene HTR3A and bipolar affective disorder.

Serotonin receptor type 3 is a ligand-gated ion channel implicated in behavioural disorders. Our objective was to identify nucleotide variants in a specific portion of the 5' region of the serotonin receptor gene (HTR3A) containing upstream open reading frames (uORFs) and to investigate their effect on bipolar disease. Mutations in uORFs have been recently shown to cause disease by changing expression on the translational level. We identified one polymorphism, C195T, and one missense mutation, C178T (Pro16Ser) within an upstream open reading frame. No significant association was found between the C195T polymorphism and bipolar affective disorder. A significant association was, however, found between the variant C178T in 156 patients with bipolar disorder compared to 156 healthy controls (P = 0.00016). To investigate the relevance of this variant on gene expression, luciferase reporter constructs containing the C178T (Pro16Ser) allele were established and compared to the C178T plus C195T and wild-type alleles. Reporter constructs containing the C178T (Pro16Ser) allele drove 245% and 138% expression compared to the wild-type allele. These findings show that the C178T(Pro16Ser) variant in HTR3A may represent a functional variant and affect the susceptibility to bipolar disorder.

5' Untranslated Regions↗
PubMed2000

No association between the dopamine D3 receptor Bal I polymorphism and schizophrenia in a family-based study of a Palestinian Arab population.

Several recent meta-analyses appear to show a weak but significant effect of both forms of the gly/ser DRD3 polymorphism in conferring risk for schizophrenia. Since most studies have employed the artifact-prone case-control design, we thought it worthwhile to examine the role of this polymorphism using a robust family-based strategy in an ethnic group not previously systematically studied in psychiatric genetics, Palestinian Arabs. We failed to obtain any evidence in 129 Palestinian triads, using the haplotype relative risk (allele frequency: Pearson chi-square = 0.009, P > 0.1, df = 1, n = 258 alleles) or transmission disequilibrium test design (chi-square = 0.38, P > 0.1, n = 86 families) for association/linkage (or increased homozygosity) of the DRD3 Bal I polymorphism to schizophrenia in our sample. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:778-780, 2000.

Alleles↗
PubMed2000

Association between a functional polymorphism in the monoamine oxidase A gene promoter and major depressive disorder.

Various polymorphisms of the X-chromosomal monoamine oxidase A (MAO-A) gene were investigated for association with affective disorders. However, none of the studied variants could consistently be associated with either major depressive or bipolar affective disorder. Recently, a positive association between panic disorder and a novel functional repeat polymorphism in the MAO-A gene promoter, with the longer alleles being more active, was reported. Since monoaminergic neurotransmission is supposed to play an important role in affective disorders, we investigated a potential association of this polymorphism with major depressive illness in a sample of 146 unrelated patients of German descent and a control group of 101 individuals with a negative life history for affective disorders. Similarly to the recent findings in panic disorder, we observed a significantly increased frequency of genotypes containing only long alleles in female patients with recurrent major depression in comparison with age- and sex-matched controls. Thus, our data suggest that an excess of high-activity MAO-A gene promoter alleles resulting in an elevated MAO-A activity is a risk factor for major depressive disorder in females. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:801-803, 2000.

Adult↗
PubMed2000

Decreased frontal lobe ratio of N-acetyl aspartate to choline in familial schizophrenia: a proton magnetic resonance spectroscopy study.

Neuropathological and neuroimaging studies suggest neuronal dysfunction in schizophrenia. N-acetyl aspartate (NAA) is a useful marker of neuronal dysfunction that can be measured with magnetic resonance spectroscopy (MRS). In the present study NAA, choline (Cho), phospho-creatine ((P)Cr), inositol containing compounds and glutamine/glutamate (Glx) were assessed in the left frontal lobe and basal ganglia of subjects with familial schizophrenia, family members with mixed psychiatric diagnoses, unaffected family members, and community controls. Concentrations of metabolites were analyzed and expressed as ratios. NAA/Cho, NAA/(P)Cr and Glx containing compounds showed a negative correlation with age in the frontal lobe. After covarying for age, subjects with schizophrenia had a significant reduction in the left frontal lobe NAA/Cho ratio compared with unaffected family members (P=0.018) as well as with community non-familial (P=0.037) controls. These MRS observations support the hypothesis of a disease-related neuronal deficit in the frontal lobe of schizophrenic patients, and relatively normal basal ganglia.

Adult↗
PubMed2000

Association study of the tryptophan hydroxylase gene and bipolar affective disorder using family-based internal controls.

The tryptophan hydroxylase (TPH) gene encodes for the rate-limiting enzyme of the serotonin metabolism and, therefore, has to be considered a major candidate for association studies in affective disorders. Recently, an association between this gene and bipolar affective disorder has been reported in a French population. We sought to replicate this finding in a German sample. Allele frequencies of a biallelic polymorphism (A218C) of the TPH gene were determined in 95 bipolar I patients and their parents. Preferential transmission of alleles from heterozygous parents to bipolar offspring was tested with the "transmission disequilibrium test" (TDT), which eliminates the contribution of population stratification to an association finding. Our sample yielded a power >90% to detect the originally reported effect. Neither allele 218A nor allele 218C were preferentially transmitted from heterozygous parents to bipolar offspring. Our results, therefore, do not support the hypothesis that the TPH gene is involved in the etiology of bipolar disorder.

Adult↗