GWA study data mining and independent replication identify cardiomyopathy-associated 5 (CMYA5) as a risk gene for schizophrenia.

We conducted data-mining analyses using the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) and molecular genetics of schizophrenia genome-wide association study supported by the genetic association information network (MGS-GAIN) schizophrenia data sets and performed bioinformatic prioritization for all the markers with P-values ≤0.05 in both data sets. In this process, we found that in the CMYA5 gene, there were two non-synonymous markers, rs3828611 and rs10043986, showing nominal significance in both the CATIE and MGS-GAIN samples. In a combined analysis of both the CATIE and MGS-GAIN samples, rs4704591 was identified as the most significant marker in the gene. Linkage disequilibrium analyses indicated that these markers were in low LD (3 828 611-rs10043986, r(2)=0.008; rs10043986-rs4704591, r(2)=0.204). In addition, CMYA5 was reported to be physically interacting with the DTNBP1 gene, a promising candidate for schizophrenia, suggesting that CMYA5 may be involved in the same biological pathway and process. On the basis of this information, we performed replication studies for these three single-nucleotide polymorphisms. The rs3828611 was found to have conflicting results in our Irish samples and was dropped out without further investigation. The other two markers were verified in 23 other independent data sets. In a meta-analysis of all 23 replication samples (family samples, 912 families with 4160 subjects; case-control samples, 11 380 cases and 15 021 controls), we found that both markers are significantly associated with schizophrenia (rs10043986, odds ratio (OR)=1.11, 95% confidence interval (CI)=1.04-1.18, P=8.2 × 10(-4) and rs4704591, OR=1.07, 95% CI=1.03-1.11, P=3.0 × 10(-4)). The results were also significant for the 22 Caucasian replication samples (rs10043986, OR=1.11, 95% CI=1.03-1.17, P=0.0026 and rs4704591, OR=1.07, 95% CI=1.02-1.11, P=0.0015). Furthermore, haplotype conditioned analyses indicated that the association signals observed at these two markers are independent. On the basis of these results, we concluded that CMYA5 is associated with schizophrenia and further investigation of the gene is warranted.

Integrating genetic, functional genomic, and bioinformatics data in a systems biology approach to complex diseases: application to schizophrenia.

The search for DNA alterations that cause human disease has been an area of active research for more than 50 years, since the time that the genetic code was first solved. In the absence of data implicating chromosomal aberrations, researchers historically have performed whole genome linkage analysis or candidate gene association analysis to develop hypotheses about the genes that most likely cause a specific phenotype or disease. Whereas whole genome linkage analysis examines all chromosomal locations without a priori predictions regarding what genes underlie susceptibility, candidate gene association studies require a researcher to know in advance the genes that he or she wishes to test (based on their knowledge of a disease). To date, very few whole genome linkage studies and candidate gene studies have produced results that lead to generalizable findings about common diseases. One factor contributing to this lack of results has certainly been the previously limited resolution of the techniques. Recent technological advances, however, have made it possible to perform highly informative whole genome linkage and association analyses, as well as whole genome transcription (transcriptome) analysis. In addition, for the first time we can detect structural DNA aberrations throughout the genome on a fine scale. Each of these four approaches has its own strengths and weaknesses, but taken together, the results from an integrated analysis can implicate highly promising novel candidate genes. Here, we provide an overview of the integrated methodology that we have used to combine high-throughput genetic and functional genomic data with bioinformatics data that have produced new insights into the potential biological basis for schizophrenia. We believe that the potential of this combined approach is greater than that of a single mode of discovery, particularly for complex genetic diseases.

Evidence for genetic heterogeneity between clinical subtypes of bipolar disorder.

We performed a genome-wide association study of 6447 bipolar disorder (BD) cases and 12 639 controls from the International Cohort Collection for Bipolar Disorder (ICCBD). Meta-analysis was performed with prior results from the Psychiatric Genomics Consortium Bipolar Disorder Working Group for a combined sample of 13 902 cases and 19 279 controls. We identified eight genome-wide significant, associated regions, including a novel associated region on chromosome 10 (rs10884920; P=3.28 × 10-8) that includes the brain-enriched cytoskeleton protein adducin 3 (ADD3), a non-coding RNA, and a neuropeptide-specific aminopeptidase P (XPNPEP1). Our large sample size allowed us to test the heritability and genetic correlation of BD subtypes and investigate their genetic overlap with schizophrenia and major depressive disorder. We found a significant difference in heritability of the two most common forms of BD (BD I SNP-h2=0.35; BD II SNP-h2=0.25; P=0.02). The genetic correlation between BD I and BD II was 0.78, whereas the genetic correlation was 0.97 when BD cohorts containing both types were compared. In addition, we demonstrated a significantly greater load of polygenic risk alleles for schizophrenia and BD in patients with BD I compared with patients with BD II, and a greater load of schizophrenia risk alleles in patients with the bipolar type of schizoaffective disorder compared with patients with either BD I or BD II. These results point to a partial difference in the genetic architecture of BD subtypes as currently defined.

Controlled comparisons of clomipramine and fluoxetine in the treatment of obsessive-compulsive disorder. Behavioral and biological results.

Treatment with fluoxetine hydrochloride was compared with treatment with clomipramine hydrochloride in two groups of patients with obsessive-compulsive disorder using two different experimental designs. In the first group of 11 patients with obsessive-compulsive disorder studied using a randomized, double-blind, crossover design, treatment with fluoxetine for 10 weeks was found to produce therapeutic effects similar to treatment with clomipramine for 10 weeks. There were significantly fewer total side effects reported during fluoxetine than clomipramine treatment. Drug tapering and placebo substitution in the 4-week crossover interval phase led to substantial relapses in obsessive-compulsive disorder symptoms and depression. Furthermore, responses to the second drug took as long to occur as responses to the first drug, although both drugs are thought to act by a common mechanism, serotonin uptake inhibition. A second group of 21 patients with obsessive-compulsive disorder that had been previously stabilized on clomipramine treatment with at least partial benefit were crossed over to fluoxetine treatment in a double-blind fashion. After 10 weeks of fluoxetine administration, most patients manifested behavioral rating scores of obsessive-compulsive disorder and depressive symptoms that were comparable with precrossover ratings completed during clomipramine treatment. A significant exacerbation in obsessive-compulsive disorder and depression ratings as well as a similar lag in therapeutic efficacy were also noted in this second cohort of patients with obsessive-compulsive disorder. Platelet 5-HT concentrations were reduced 95% during both clomipramine and fluoxetine treatment periods. These results suggest that fluoxetine may represent a viable alternative to clomipramine in the treatment of obsessive-compulsive disorder, although further studies with larger sample sizes are needed.

Return of symptoms after discontinuation of clomipramine in patients with obsessive-compulsive disorder.

To evaluate the need for maintenance drug therapy in patients with obsessive-compulsive disorder, the authors assessed 21 patients with obsessive-compulsive disorder who manifested sustained improvement during 5 to 27 months of clomipramine treatment and who agreed to participate in a double-blind discontinuation study. Of 18 patients who completed the study, 16 had substantial recurrence of obsessive-compulsive symptoms by the end of the 7-week placebo period. In addition, 11 had a significant increase in depressive symptoms. Treatment duration before discontinuation of clomipramine was not related to the frequency or severity of obsessive-compulsive or depressive symptom appearance. These findings suggest that prolonged drug treatment may be warranted for obsessive-compulsive disorder.

Obsessive-compulsive disorder in patients with schizophrenia or schizoaffective disorder.

OBJECTIVE: The authors evaluated the frequency of DSM-III-R obsessive-compulsive disorder in patients with a primary diagnosis of schizophrenia or schizoaffective disorder. METHOD: Patients with schizophrenia (N = 52) or schizoaffective disorder (N = 25) were evaluated for the presence of obsessions and compulsions by means of the Structured Clinical Interview for DSM-III-R, the Yale-Brown Obsessive Compulsive Scale, chart review, and contact with the treating clinicians. RESULTS: Six (7.8%) of the 77 patients met the DSM-III-R criteria for both obsessive-compulsive disorder and schizophrenia or schizoaffective disorder. CONCLUSIONS: These findings suggest that obsessive-compulsive disorder occurs in a substantial percentage of patients with schizophrenia or schizoaffective disorder. The addition of medications targeted at obsessive-compulsive disorder may be beneficial to these patients but requires systematic evaluation.

Controlled comparison of buspirone and clomipramine in obsessive-compulsive disorder.

Eighteen outpatients with obsessive-compulsive disorder were treated with either buspirone, a partial serotonin agonist, or clomipramine, a serotonin uptake inhibitor, in a double-blind, random-assignment study. Both drugs led to statistically significant and similar improvements in scores on the Yale-Brown Obsessive-Compulsive Rating Scale and other obsessive-compulsive and depression scales. This preliminary result warrants further exploration with a larger sample and other serotonergic agents.

Summary of the Third World Congress on Psychiatric Genetics.

A summary of the proceedings of the third world congress on psychiatric genetics is presented. The meeting was held in New Orleans on October 2-5, 1993 and brought together researchers from around the world. The International Society of Psychiatric Genetics sponsored and organized this meeting. Rapid advances of the last few years were reviewed and discussed in terms of their impact on the evolution of experimental design. The importance of definition of heritable clinical phenotypes, and the need to continue to enhance analytic methods were stressed as a priority for the field.

Association between homozygosity at the COMT gene locus and obsessive compulsive disorder.

A functional polymorphism in the coding region of the catechol O-methyltransferase (COMT) gene has been reported in previous studies to be associated with obsessive compulsive disorder (OCD), particularly in males [Karayiorgou et al., 1997, 1999]. Using a family-based population analysis, we attempted to replicate these findings in a group of 72 OCD patient/parent trios collected from Buffalo, New York, and Toronto, Canada. Analysis of allele and genotype frequencies using the haplotype relative risk (HRR) and transmission disequilibrium test (TDT) did not identify an association between a particular allele and OCD as had been previously reported. Furthermore, no evidence was found to support the findings of a gender-based association for COMT when the patients and the parents of the same gender were compared. However, our genotype results (n = 72) demonstrate a tendency for association between homozygosity at the COMT locus and OCD (homozygosity analysis: chi(2) = 5.66, P = 0.017; genotypic analysis: chi(2) = 5.78, P = 0.056). Although these findings do not replicate the previous reports, they do provide limited support to demonstrate a trend for homozygosity at the COMT locus in the OCD patients and, in turn, further implicate a potential role for COMT in the genetic etiology of OCD. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:721-724, 2000.

Review of the putative association of dopamine D2 receptor and alcoholism: a meta-analysis.

Eight recent studies have focused on the putative association of the dopamine D2 receptor (DRD2) gene and alcoholism. In this report, these studies are reviewed and the data and findings are examined in a meta-analysis. Four reports find a statistically significant increased risk for alcoholism in subjects carrying the A1 allele and 4 failed to observe a significant increase in risk. Overall, our meta-analysis of the results from all 8 studies supported a statistically significant association between the A1 allele of DRD2 and alcoholism, with an apparent increase in relative risk associated with increased severity of alcoholism. These results must be interpreted cautiously because the A1 allele of DRD2 varies significantly in frequency from one population to another. This variability in the population frequency of the A1 allele could result in an apparent association resulting from unrelated population differences. These findings support the need for carefully designed studies that minimize the ethnic heterogeneity of the subject and control populations.

Selection of homogeneous populations for genetic study: the Portugal genetics of psychosis project.

Molecular genetic studies of psychiatric disorders must face the possibility that despite the significant contribution of genetic factors to the expression of syndromes like schizophrenia, these syndromes may be a heterogeneous collection of genetic and non-genetic illnesses. These illnesses may be etiologically distinct from each other and still share many clinical features in common. Linkage studies of families with multiple affected members tend to favor the selection of genetic forms of a syndrome but can still represent a heterogeneous set of different genetic illnesses. To limit the potential genetic heterogeneity of a study sample, we selected a population that was geographically isolated and was historically relatively genetically homogeneous. We then assessed the relative level of homogeneity utilizing a surname analysis of the population of the Azores, mainland Portugal, rural USA, and urban USA. The average number of families with the same last name corrected for population size in the Azores is 30.88, in Coimbra it is 21.42, compared to 1.13 in a rural American population and 0.38 in an urban American population. The results of this analysis indicate that the Azores have the highest degree of homogeneity, and mainland Portugal has a high degree of homogeneity.

Detection of expansion regions in Portuguese bipolar families.

We have studied 24 families with multiple affected members with bipolar disorder to test the hypothesis that in those families clinically showing genetic anticipation [Macedo et al., 1999] we would find large repeat expansions. The families meeting inclusion criteria had a minimum of two affected members over two generations and showed marked anticipation both in terms of age of onset and disease severity. We used the repeat expansion detection (RED) method to test patients (n = 24) and controls from these families and unrelated controls (n = 53). We also genotyped patients and family members from two families with large expansions at the known expansion loci on chromosomes 13, 17, and 18. The RED method revealed a higher number of large expansions in patients compared with controls (t-test; P < 0.0055: Mann-Whitney U; P = 0.02). The patients with the largest expansions were typed at the specific loci on chromosomes 13, 17, and 18 and the chromosome 18 expansion locus segregated with disease in one family, and a second family showed segregation with the expansion located at the SCA8 locus on chromosome 13. Genetic anticipation had been analyzed in this cohort of families, with correction for potential ascertainment bias, possible proband effects, cohort effects, regression to the mean, gender effects, and maternal vs. paternal transmission. None of these potential confounds appeared to account for the observed anticipation. We also identified that the presence of large expansions in affected family members derives primarily from two families from the genetically isolated Azores population. One family shows segregation with the chromosome 18 locus, whereas the other family segregates with expansions at the SCA8 locus. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:854-857, 2000.

Evidence for linkage disequilibrium between the alpha 7-nicotinic receptor gene (CHRNA7) locus and schizophrenia in Azorean families.

Recent studies have suggested that the alpha 7-nicotinic receptor gene (CHRNA7) may play a role in the pathogenesis of schizophrenia. The alpha 7-nicotinic receptor gene (CHRNA7) is involved in P50 auditory sensory gating deficits, and the genomic locus for this gene lies in the chromosome 15q13-14 regions. The human gene is partially duplicated (exons 5-10) with four novel upstream exons. The marker D15S1360 has been shown to be significantly linked with the phenotype of abnormal P50 suppression in schizophrenia families. The marker L76630 is 3 kb in the 3' direction from the last exon of the CHRNA7 gene and is located in the duplicated region. The function of the two L76630 copies is unknown. We genotyped three polymorphic markers D15S1360, D15S165, and L76630 that are localized in a genomic fragment containing the CHRNA7 in 31 Azorean schizophrenia families/trios (including 41 schizophrenia individuals and 97 unaffected families members). An overall analysis utilizing the family-based association test revealed significant linkage disequilibrium between L76630 and schizophrenia (P = 0.0004). Using the extended transmission disequilibrium test and limiting the analysis to one triad per family, transmission disequilibrium of D15S1360 was near significance (P = 0.078). The 15q13 region overlaps with the location of two well-known genomically imprinted disorders: Angelman syndrome and Prader-Willi syndrome. Therefore, we investigated maternal and paternal meioses. We found significant transmission disequilibrium for D15S1360 through paternal transmission (P = 0.0006) in our schizophrenia families. The L76630 marker showed a significant disequilibrium in maternal transmissions (P = 0.028). No parent-of-origin effect was found in D15S165. Overall, our results suggest that the CHRNA7 may play a role in schizophrenia in these families. A parent of origin effect may be present and requires further study.

Long repeat tracts at SCA8 in major psychosis.

Expansion at a recently identified unstable trinucleotide repeat on chromosome 13q21 has been reported as the molecular cause for spinocerebellar ataxia type 8 (SCA8). The trinucleotide repeat, which consists of a [CTA]n repeat and adjacent [CTG]n repeat, was reported to have a pathogenic range of 107-127 CTG repeats (or 110-130 combined CTA and CTG repeats) in a large ataxia kindred. This repeat region was also cloned by our group from a bipolar affective disorder (BPAD) patient, who has approximately 600 combined repeats, and large alleles (>100 repeats) were reported to be present in 0.7% of controls and 1.5% of major psychosis patients (n = 710 and n = 1,120, respectively). We have followed up these findings by screening three new samples of BPAD and schizophrenia (SCZ) patients and controls, including 272 individuals from 14 BPAD families from Sweden, 130 individuals from 32 SCZ and BPAD families/trios from the Azores Islands, and 206 SCZ individuals from the United Kingdom and Ireland, and 219 matched controls. We found large repeat alleles above the SCA8 pathogenic range in individuals from 3 of 32 Azorean pedigrees and in 1 of 206 SCZ individuals from the United Kingdom, and repeat alleles within the SCA8 pathogenic range in 1 of 14 Swedish families. Although the rarity of major psychosis patients carrying the SCA8 expansion mutation would require a much larger sample size to reach statistical significance, these results support the previously reported observation of increased occurrence of large repeats at SCA8 in major psychosis. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:873-876, 2000.

Current issues in the pharmacologic management of obsessive compulsive disorder.

In spite of significant advances in the development of behavioral and pharmacologic strategies for the treatment of obsessive compulsive disorder, little is known about the comparative efficacy and safety of those treatments. In addition, questions about the dose and duration in maintenance treatment remain unknown. This article reviews current issues in the pharmacologic management of patients with obsessive compulsive disorder.

Olanzapine therapy in treatment-resistant psychotic mood disorders: a long-term follow-up study.

BACKGROUND: Recent studies suggest a role for the atypical antipsychotic olanzapine in the acute treatment of psychotic mood disorders, but long-term data are unavailable. The purpose of this naturalistic study was to determine the long-term effectiveness and tolerability of olanzapine as add-on therapy in psychotic mood disorders. METHOD: Hospital records were reviewed for 125 inpatients at the state psychiatric hospital in Buffalo, N.Y., who received at least 6 weeks of add-on olanzapine treatment for psychotic mood disorders (schizoaffective disorders [bipolar and depressive type], bipolar disorders [I, II, and NOS], and major depressive disorder). A group of schizophrenic patients served as a control group (N = 50). Baseline measures, including age, gender, number of hospitalizations in the 2 years prior to olanzapine treatment, concomitant medications, the Clinical Global Impressions scale (CGI), and the Global Assessment of Functioning-Equivalent (GAF-EQ) and Kennedy Axis V psychological impairment, violence, social skills, and activities of daily living subscale scores, were obtained. Follow-up information was obtained from the patients at least 6 months after initiation of olanzapine or by chart review and discussion with the treating psychiatrist. Patients with a diagnosis of psychotic mood disorders were compared with patients with the non-affective psychotic disorder (schizophrenia) on a variety of outcome measures. RESULTS: Follow-up information was available on 102 patients (82%). Mean follow-up was 15 months; 50 (49%) of the 102 patients remained on olanzapine treatment at follow-up (32 psychotic mood disorder, 18 schizophrenic). The primary reason for discontinuation in both groups was lack of response. Both the psychotic mood disorder and schizophrenic groups had comparable outcomes on the CGI and GAF-EQ. Improvement on the Kennedy Axis V psychological impairment and social skills subscales was seen only in the psychotic mood disorders group (p < .01); both groups showed significant (p < .02) improvement in the violence subscale. Sustained mood-stabilizing effect was evident in only 7/27 (26%) of the psychotic mood disorders patients continuing on add-on olanzapine treatment at follow-up. CONCLUSION: Lack of response was the primary reason for discontinuation of add-on olanzapine in both groups. Mood symptoms predicted a better response to add-on olanzapine in patients with psychotic mood disorders on selective outcome measures. However, only 26% of the patients with psychotic mood disorders sustained a clinically meaningful mood-stabilizing effect with add-on olanzapine treatment at follow-up.

Beyond depression: citalopram for obsessive-compulsive disorder.

Obsessive-compulsive disorder (OCD) and serotonin reuptake inhibitors became inextricably joined with the discovery of their effectiveness for the treatment of OCD in 1969 and 1976. The specificity of response of OCD to serotonin reuptake inhibitors has provided an important platform for the exploration of the neurobiology of OCD. This knowledge has come from many different areas of investigation, including neuroimaging, neuroimmunology and pharmacologic challenge studies. As the research into the pharmacologic treatment of OCD has progressed, a number of serotonin reuptake inhibitors have been approved and marketed for the treatment of OCD. These agents include clomipramine, sertraline, paroxetine, fluoxetine, and fluvoxamine. Because these agents share the same mechanism of action (serotonin reuptake inhibition), choosing which agent to use must be based on other parameters. These include differences in efficacy, dosing, and side-effect profile. Citalopram, a newly marketed selective serotonin reuptake inhibitor could offer some advantages over those agents currently marketed. Theoretically, it should also be effective in the treatment of OCD. In treating depression, it has been shown to have minimal side-effects, low risk of withdrawal symptoms, and little possibility of interaction with other agents.

Comorbidity of obsessive-compulsive and psychotic symptoms: a review.

Co-occurrence of psychotic and obsessive-compulsive symptoms was first reported nearly 70 years ago. This paper reviews published reports from two perspectives: psychotic disorders with obsessive-compulsive symptoms and obsessive-compulsive disorder (OCD) with psychotic symptoms. Older investigations reported a low rate of comorbidity between these two disorders, but more-recent studies, in which systematic diagnostic criteria have been used, have suggested that the rate of co-occurrence of symptoms is higher than was previously thought. The difficulty in diagnosing patients with obsessive-compulsive and psychotic symptoms is reviewed, and the importance of this distinction for treatment and prognosis is discussed. Although the comorbid diagnosis of schizophrenia and OCD, or of OCD and psychotic features, seems to portend a worse prognosis than for either illness alone, the available data suggest that some patients with schizophrenia and OC symptoms may improve with traditional antiobsessional treatment.

Obsessive-compulsive disorder as a 5-HT subsystem-related behavioural disorder.

Involvement of the brain serotonin (5-HT) neurotransmitter system in obsessive-compulsive disorder (OCD) was originally suggested on the basis of therapeutic effects found with the semiselective serotonin uptake inhibitor, clomipramine. More recent studies directly comparing clomipramine with non-selective or norepinephrine-selective uptake inhibitors, such as desipramine or nortriptyline, as well as studies with new, more selective serotonin uptake inhibitors, including fluvoxamine and fluoxetine, have supported that hypothesis. Clomipramine's antiobsessional effect has been augmented with the serotonin precursor, L-tryptophan, or with lithium, which has prominent serotonergic effects. Patients whose OCD symptoms improved on clomipramine worsened when the drug was discontinued (regardless of duration of therapy) and improved when clomipramine was reinstituted. OCD symptoms also worsened when metergoline, a 5-HT antagonist, was given to patients who had improved with clomipramine. Metergoline given alone had no effect. Administration of m-chlorophenylpiperazine (m-CPP), a 5-HT receptor agonist, to untreated OCD patients increased their anxiety, depression, and dysphoria, and exacerbated their OC symptoms. After 4 months of clomipramine therapy, m-CPP failed to produce the same behavioural effects, suggesting an alteration of a 5-HT subsystem (possibly downregulation of some 5-HT receptors). The data reviewed suggest an important role for an abnormal brain 5-HT subsystem in patients with OCD.