Fine-mapping scan of bipolar disorder susceptibility loci in Latino pedigrees.

We previously identified bipolar disorder (BD) susceptibility loci on 8q24, 14q32, and 2q12-14 in a genome-wide nonparametric linkage screen in a Latino cohort. We now perform a fine mapping analysis using a dense map of additional SNPs to identify BD susceptibility genes within these regions. One thousand nine hundred and thirty-eight individuals with Latino ancestry (880 individuals with BD Type I or Schizoaffective, Bipolar Type) from 416 Latino pedigrees from the United States, Mexico, Costa Rica, and Guatemala were genotyped with 3,074 SNPs to provide dense coverage of the 8q24 (11.5 cM), 14q32 (7.5 cM), and 2q12-14 (6.5 cM) chromosomal loci. Single-marker association tests in the presence of linkage were performed using the LAMP software. The top linkage peak (rs7834818; LOD = 5.08, p = 3.30E - 5) and associated single marker (rs2280915, p = 2.70E - 12) were located within FBXO32 on 8q24. On chromosome 2, the top linkage peak (rs6750326; LOD = 5.06, p = 3.50E - 5) and associated single marker (rs11887088, p = 2.90E - 6) were located in intragenic regions near ACTR3 and DPP10. None of the additional markers in the region around chromosome 14q32 met significance levels for linkage or association. We identified six SNPs on 2q12-q14 and one SNP in FBXO32 on 8q24 that were significantly associated with BD in this Latino cohort.

Replication of genome-wide association study (GWAS) susceptibility loci in a Latino bipolar disorder cohort.

OBJECTIVES: Recent genome-wide association studies (GWASs) have identified numerous putative genetic polymorphisms associated with bipolar disorder (BD) and/or schizophrenia (SC). We hypothesized that a portion of these polymorphisms would also be associated with BD in the Latino American population. To identify such regions, we tested previously identified genetic variants associated with BD and/or SC and ancestral haploblocks containing these single nucleotide polymorphisms (SNPs) in a sample of Latino subjects with BD. METHODS: A total of 2254 Latino individuals were genotyped for 91 SNPs identified in previous BD and/or SC GWASs, along with selected SNPs in strong linkage disequilibrium with these markers. Family-based single marker and haplotype association testing was performed using the PBAT software package. Empirical P-values were derived from 10 000 permutations. RESULTS: Associations of eight a priori GWAS SNPs with BD were replicated with nominal (P≤.05) levels of significance. These included SNPs within nuclear factor I A (NFIA), serologically defined colon cancer antigen 8 (SDCCAG8), lysosomal associated membrane protein 3 (LAMP3), nuclear factor kappa B subunit 1 (NFKB1), major histocompatibility complex, class I, B (HLA-B) and 5'-nucleotidase, cytosolic II (NT5C2) and SNPs within intragenic regions microRNA 6828 (MIR6828)-solute carrier family 7 member 14 (SLC7A14) and sonic hedgehog (SHH)-long intergenic non-protein coding RNA 1006 (LINC01006). Of the 76 ancestral haploblocks that were tested for associations with BD, our top associated haploblock was located in LAMP3; however, the association did not meet statistical thresholds of significance following Bonferroni correction. CONCLUSIONS: These results indicate that some of the gene variants found to be associated with BD or SC in other populations are also associated with BD risk in Latinos. Variants in six genes and two intragenic regions were associated with BD in our Latino sample and provide additional evidence for overlap in genetic risk between SC and BD.

Identification of circadian gene variants in bipolar disorder in Latino populations.

BACKGROUND: Variations in circadian genes can impact biological rhythms. Given the rhythm disturbances that characterize bipolar disorder (BD), genes encoding components of molecular clocks are good candidate genes for the illness. METHODS: A family based association analysis of circadian gene single nucleotide polymorphisms (SNPs) and BD was conducted in Latino pedigrees. 884 individuals from 207 pedigrees (473BP phenotype and 411 unaffected family members) were genotyped. Family based single marker association testing was performed. Ancestral haplotypes (SNPs found to be in strong LD defined using confidence intervals) were also tested for association with BD. RESULTS: Multiple suggestive associations between circadian gene SNPs and BD were noted. These included CSNK1E (rs1534891, p=0.00689), ARNTL (rs3789327, p=0.021172), CSNK1D (rs4510078, p=0.022801), CLOCK (rs17777927, p=0.031664). Individually, none of the SNPs were significantly associated with BD after correction for multiple testing. However, a 4-locus CSNK1E haplotype encompassing the rs1534891 SNP (Z-score=2.685, permuted p=0.0076) and a 3-locus haplotype in ARNTL (Z-score=3.269, permuted p=0.0011) showed a significant association with BD. LIMITATIONS: Larger samples are required to confirm these findings and assess the relationship between circadian gene SNPs and BD in Latinos. CONCLUSIONS: The results suggest that ARNTL and CSKN1E variants may be associated with BD. Further studies are warranted to assess the relationships between these genes and BD in Latino populations.

A national cohort study of the association between the polytrauma clinical triad and suicide-related behavior among US Veterans who served in Iraq and Afghanistan.

OBJECTIVES: We examined the association of posttraumatic stress disorder (PTSD), traumatic brain injury, and chronic pain-the polytrauma clinical triad (PCT)-independently and with other conditions, with suicide-related behavior (SRB) risk among Operation Enduring Freedom (OEF; Afghanistan) and Operation Iraqi Freedom (OIF) veterans. METHODS: We used Department of Veterans Affairs (VA) administrative data to identify OEF and OIF veterans receiving VA care in fiscal years 2009-2011; we used International Classification of Diseases, Ninth Revision, Clinical Modification codes to characterize 211652 cohort members. Descriptive statistics were followed by multinomial logistic regression analyses predicting SRB. RESULTS: Co-occurrence of PCT conditions was associated with significant increase in suicide ideation risk (odds ratio [OR] = 1.9; 95% confidence interval [CI]=1.5, 2.4) or attempt and ideation (OR=2.6; 95% CI=1.5, 4.6), but did not exceed increased risk with PTSD alone (ideation: OR=2.3; 95% CI=2.0, 2.6; attempt: OR=2.0; 95% CI=1.4, 2.9; ideation and attempt: OR=1.8; 95% CI=1.2, 2.8). Ideation risk was significantly elevated when PTSD was comorbid with depression (OR=4.2; 95% CI=3.6, 4.8) or substance abuse (OR=4.7; 95% CI = 3.9, 5.6). CONCLUSIONS: Although PCT was a moderate SRB predictor, interactions among PCT conditions, particularly PTSD, and depression or substance abuse had larger risk increases.

A genome-wide linkage scan of bipolar disorder in Latino families identifies susceptibility loci at 8q24 and 14q32.

A genome-wide nonparametric linkage screen was performed to localize Bipolar Disorder (BP) susceptibility loci in a sample of 3757 individuals of Latino ancestry. The sample included 963 individuals with BP phenotype (704 relative pairs) from 686 families recruited from the US, Mexico, Costa Rica, and Guatemala. Non-parametric analyses were performed over a 5 cM grid with an average genetic coverage of 0.67 cM. Multipoint analyses were conducted across the genome using non-parametric Kong & Cox LOD scores along with Sall statistics for all relative pairs. Suggestive and significant genome-wide thresholds were calculated based on 1000 simulations. Single-marker association tests in the presence of linkage were performed assuming a multiplicative model with a population prevalence of 2%. We identified two genome-wide significant susceptibly loci for BP at 8q24 and 14q32, and a third suggestive locus at 2q13-q14. Within these three linkage regions, the top associated single marker (rs1847694, P = 2.40 × 10(-5)) is located 195 Kb upstream of DPP10 in Chromosome 2. DPP10 is prominently expressed in brain neuronal populations, where it has been shown to bind and regulate Kv4-mediated A-type potassium channels. Taken together, these results provide additional evidence that 8q24, 14q32, and 2q13-q14 are susceptibly loci for BP and these regions may be involved in the pathogenesis of BP in the Latino population.

A survey of perceived barriers and attitudes toward mental health care among OEF/OIF veterans at VA outpatient mental health clinics.

OBJECTIVE: In an effort to improve our understanding of perceived treatment barriers among veterans of Operations Enduring Freedom and Iraqi Freedom (OEF/OIF) relative to other era veterans, the current study examined veteran attitudes and beliefs about mental health treatment and treatment-seeking, and perceived patient and institution-level logistical barriers to care. METHOD: A survey was conducted among 434 Combat veterans seeking care in nine Veterans Affairs mental health care outpatient clinics. RESULTS: When compared to Vietnam and Gulf War veterans, OEF/OIF veterans were significantly more likely to endorse negative treatment attitudes as possible barriers to care. OEF/OIF veterans were also more likely than Vietnam veterans to endorse conflicting work demands as a potential barrier, although this was the only logistical barrier for which OEF/OIF veterans' responses differed significantly from those of veterans of other eras. Among OEF/OIF veterans, older veterans were more likely than younger veterans to endorse barriers related to cost and time commitments. CONCLUSIONS: These findings suggest an important role for outreach and engagement strategies that address attitudinal barriers to treatment utilization among veteran populations.

Suggestive evidence for association between L-type voltage-gated calcium channel (CACNA1C) gene haplotypes and bipolar disorder in Latinos: a family-based association study.

OBJECTIVES: Through recent genome-wide association studies (GWASs), several groups have reported significant association between variants in the calcium channel, voltage-dependent, L-type, alpha 1C subunit (CACNA1C) and bipolar disorder (BP) in European and European-American cohorts. We performed a family-based association study to determine whether CACNA1C is associated with BP in the Latino population. METHODS: This study included 913 individuals from 215 Latino pedigrees recruited from the USA, Mexico, Guatemala, and Costa Rica. The Illumina GoldenGate Genotyping Assay was used to genotype 58 single-nucleotide polymorphisms (SNPs) that spanned a 602.9-kb region encompassing the CACNA1C gene including two SNPs (rs7297582 and rs1006737) previously shown to associate with BP. Individual SNP and haplotype association analyses were performed using Family-Based Association Test (version 2.0.3) and Haploview (version 4.2) software. RESULTS: An eight-locus haplotype block that included these two markers showed significant association with BP (global marker permuted p = 0.0018) in the Latino population. For individual SNPs, this sample had insufficient power (10%) to detect associations with SNPs with minor effect (odds ratio = 1.15). CONCLUSIONS: Although we were not able to replicate findings of association between individual CACNA1C SNPs rs7297582 and rs1006737 and BP, we were able to replicate the GWAS signal reported for CACNA1C through a haplotype analysis that encompassed these previously reported significant SNPs. These results provide additional evidence that CACNA1C is associated with BP and provides the first evidence that variations in this gene might play a role in the pathogenesis of this disorder in the Latino population.

A case control study of the implementation of change model versus passive dissemination of practice guidelines for compliance in monitoring for metabolic syndrome.

We developed an intervention to improve compliance with guidelines for monitoring metabolic syndrome and compared compliance prior to intervention and three times post-intervention at three community mental health clinics in Texas. One test clinic received intervention and two other clinics served as controls. Fifty random charts were reviewed from each clinic for three specific, 1-2 weeks periods over the course of 18 months. There were significant improvements in the ordering of labs, the presence of lab results in the chart, and documentation of blood pressure, body mass index and waist circumference in the intervention clinic over time in comparison to the control clinics. Documented evidence of physician action with respect to out of range values remained low. Metabolic monitoring is a multi-step process. Removing barriers, creating specific procedures, and dedicating staff resources can improve compliance with monitoring.

Can medication management coordinators help improve continuity of care after psychiatric hospitalization?

OBJECTIVE: This demonstration project examined whether medication management coordinators enhanced continuity of care from inpatient facilities to an outpatient public mental health clinic. METHODS: From 2004 to 2008, patients (N=325) hospitalized with schizophrenia or schizoaffective or bipolar disorder enrolled in a medication management program before discharge or at their first clinic appointment. Medication management coordinators supplemented existing clinic practices by identifying recently hospitalized patients, providing inpatient and outpatient prescribing clinicians with patients' complete medication history, meeting with patients for six months postdischarge to assess clinical status and provide medication education, and advocating guideline-concordant prescribing. Recently discharged patients (N=345) assigned to a different outpatient clinic within the same agency served as the comparison group. Intent-to-treat, repeated-measures analyses for mixed models compared the groups' number of hospital admissions, hospital days, and medication appointments kept and use of nurse or case manager contact hours and emergency or crisis services during the 12 months before enrollment, the six-month intervention, and the six-month follow-up period. RESULTS: After discharge, individuals enrolled in medication management were more likely than comparison patients to attend outpatient appointments, and they had more medication visits and nurse or case manager treatment hours than the comparison group. Use of hospital and crisis or emergency services by all patients decreased. Almost one-third of patients never attended an outpatient appointment after hospital discharge. CONCLUSIONS: Although this program succeeded in improving continuity of care, additional interventions may be required to reduce rehospitalization and crisis care.

Barriers to, and strategies for, starting a long acting injection clinic in a community mental health center.

As many as 50% of patients with schizophrenia do not take oral antipsychotic medications as prescribed, yet long acting injections are rarely utilized. Community agencies that serve this population are often over-burdened and poorly funded. There are negative attitudes on the part of both physicians and consumers about injections. Transportation and logistics are often problematic. We describe the unique opportunity provided by the need for bi-weekly or monthly injections to establish a recovery-oriented group around injection visits. Our approach discusses methods and resources to help overcome some of the common barriers by establishing advocates within the agency, establishing necessary infrastructure, providing education for consumers, providers, and staff, sharing information about successful outcomes with clinic staff and working through billing issues. We also recommend public advocacy on the part of the clinic and consumers to work with state funding sources to change regulations that may limit appropriate clinical care.

Factors in second-generation antipsychotic switching patterns in a national sample of older veterans with schizophrenia.

OBJECTIVE: A 2004 consensus statement by the American Psychiatric Association and other groups noted that metabolic side effects of second-generation antipsychotics require monitoring. To reduce risk, prescribers may consider factors differentially associated with development of metabolic abnormalities, such as age, gender, and race-ethnicity. As part of a study of older patients with schizophrenia (50-102 years), this study evaluated factors associated with antipsychotic switches and switches that incurred a greater or lesser metabolic risk. METHODS: Administrative data were analyzed for a national cohort of 16,103 Veterans Health Administration patients with schizophrenia receiving second-generation antipsychotics. Multinomial logistic regression predicted the likelihood of switches from 2002 to 2003 and again from 2004 to 2005. RESULTS: At baseline nearly half the patients (45%) had a diagnosis of hypertension, a third (34%) had dyslipidemia, and 15% had a diagnosis of obesity. In both periods diabetes was associated with switches to lower-risk antipsychotics, and older patients were likely to experience neutral or no switches. Women were more likely to experience switches to higher-risk antipsychotics in 2004-2005. CONCLUSIONS: General medical conditions potentially associated with antipsychotic-related metabolic concerns were common; however, half of these patients were prescribed medication that made them liable to developing metabolic problems. Modest evidence suggests that metabolic considerations became a higher priority during the study. Future research should investigate the differential impact of antipsychotics on metabolic dysregulation for women and elderly patients. Findings underscore the need to monitor metabolic parameters of older patients taking antipsychotics.

Public-academic partnerships: tools for mental health agencies to evaluate research protocols.

Research involving community mental health center clients, resources, or both can affect clinical care, administrative processes, and costs. To help agencies identify and quantify these effects, a stakeholder group examined and discussed a range of protocols and then developed questionnaires and rating scales for agency use. The purpose of these materials is to make explicit the risks, costs, and benefits of a research protocol so an agency can make informed decisions about protocol approval and implementation. The goal of this work was to promote the conduct of appropriate research in community mental health settings while reducing risks to the agency and its clientele.

Association of serotonin transporter promoter gene polymorphism (5-HTTLPR) with depression in Costa Rican schizophrenic patients.

Depression and suicidal behavior are frequently observed in patients with schizophrenia. The serotonin transporter protein regulates serotonergic signaling at synapses and is encoded by a single gene (SLC6A4; Locus Link ID: 6532), located at 17q11.1-q12 with two polymorphic variants (the short and the long allele). The short allele of serotonin transporter gene has been associated with depression and suicidality in individuals who suffered negative life events and with depression in individuals with chronic psychosis.. Subjects were recruited from a genetic study of schizophrenia conducted in Costa Rica. The authors replicated their previous research, using a more narrow phenotype (only schizophrenic subjects) and a more ethnically homogenous sample (only Costa Rican schizophrenic individuals who were not included in the previous study). The authors hypothesized that subjects with at least one copy of the serotonin transporter promoter gene polymorphism (5-HTTLPR) "s" allele would have a greater history of lifetime depression and suicidability rate than those who had an "l/l" genotype. The authors analyzed 155 subjects with a DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition) diagnosis of schizophrenia (73% male, age at interview 38.3, SD = 11.23). The genotype distribution was "ss" 58 (37%), "sl" 69 (45%), and "ll" 28 (18%). In the secondary analysis, the authors explored association of the "s" allele with lifetime history of suicide behavior in 173 subjects (18 more subjects than primary analysis because schizophrenic individuals were included regardless of history of depression). The authors found that subjects carrying at least one short allele had a significant increased lifetime risk for depressive syndromes (chi(2) = 5.4, df = 1, P = 0.02; odds ratio [OR] = 2.7, 95% confidence interval [CI] = 1.15-6.3). No association was found for suicidal behavior in the same sample (chi(2) = 0.928, P = 0.629). In conclusion, the genotype at the 5-HTTLPR promoter polymorphic locus increases the risk of developing major depression but not suicidal behavior during the course of the schizophrenia in these patients. Due to the small sample size, these results should be followed by definitive replication.

Substance use disorder comorbidity with schizophrenia in families of Mexican and Central American ancestry.

OBJECTIVES: The aims of this study were to estimate the frequency and course of substances use disorders in Latino patients with schizophrenia and to ascertain risk factors associated with substance use disorders in this population. METHOD: We studied 518 subjects with schizophrenia recruited for a genetic study from the Southwest United States, Mexico, and Central America (Costa Rica and Guatemala). Subjects were assessed using structured interviews and a best estimate consensus process. Logistic regression, chi(2), t test, Fisher's exact test, and Yates' correction, as appropriate, were performed to assess the sociodemographic variables associated with dual diagnosis. We defined substance use disorder as either alcohol or substance abuse or dependence. RESULTS: Out of 518 patients with schizophrenia, 121 (23.4%) had substance use disorders. Comorbid substance use disorders were associated with male gender, residence in the United States, immigration of Mexican men to the United States, history of depressive syndrome or episode, and being unemployed. The most frequent substance use disorder was alcohol abuse/dependence, followed by marijuana abuse/dependence, and solvent abuse/dependence. CONCLUSION: This study provides data suggesting that depressive episode or syndrome, unemployment, male gender, and immigration of Mexican men to the United States were factors associated with substance use disorder comorbidity in schizophrenia. Binary logistic regression showed that country of residence was associated with substance use disorder in schizophrenic patients. The percentage of subjects with comorbid substance use disorders was higher in the Latinos living in the United States compared with subjects living in Central America and Mexico.

Neurocognitive endophenotypes for bipolar disorder identified in multiplex multigenerational families.

CONTEXT: Although genetic influences on bipolar disorder are well established, localization of genes that predispose to the illness has proven difficult. Given that genes predisposing to bipolar disorder may be transmitted without expression of the categorical clinical phenotype, a strategy for identifying risk genes is to identify and map quantitative intermediate phenotypes or endophenotypes. OBJECTIVE: To adjudicate neurocognitive endophenotypes for bipolar disorder. DESIGN: All participants underwent diagnostic interviews and comprehensive neurocognitive evaluations. Neurocognitive measures found to be heritable were entered into analyses designed to determine which test results are impaired in affected individuals, are sensitive to the genetic liability for the illness, and are genetically correlated with affection status. SETTING: Central valley of Costa Rica; Mexico City, Mexico; and San Antonio, Texas. PARTICIPANTS: Seven hundred nine Latino individuals participated in the study. Of these, 660 were members of extended pedigrees with at least 2 siblings diagnosed as having bipolar disorder (n = 230). The remaining subjects were community control subjects drawn from each site who did not have a personal or family history of bipolar disorder or schizophrenia. MAIN OUTCOME MEASURE: Neurocognitive test performance. RESULTS: Two of the 22 neurocognitive variables were not significantly heritable and were excluded from subsequent analyses. Patients with bipolar disorder were impaired on 6 cognitive measures compared with nonrelated healthy controls. Nonbipolar first-degree relatives were impaired on 5 of these, and the following 3 tests were genetically correlated with affection status: Digit Symbol Coding Task, Object Delayed Response Task, and immediate facial memory. CONCLUSION: This large-scale extended pedigree study of cognitive functioning in bipolar disorder identifies measures of processing speed, working memory, and declarative (facial) memory as candidate endophenotypes for bipolar disorder.

Social and clinical comparison between schizophrenia and bipolar disorder type I with psychosis in Costa Rica.

INTRODUCTION: Schizophrenia (SC) and bipolar disorder (BP) are two of the most severe and incapacitating mental disorders. It has been questioned whether these two conditions designate distinct illnesses with different etiologies or whether they represent different ends of a clinical spectrum with a common etiology. MATERIALS AND METHODS: This study compares social and clinical characteristics of 84 SC and 84 BP subjects from the Costa Rican Central Valley (CRCV) using information from the DIGS, FIGS and psychiatric records. Each of these subjects had a best estimate lifetime consensus diagnosis of either bipolar type I or SC. RESULTS: Subjects with SC differed from subjects with BP in social adjustment measures like marital and employment status, and number of children. Both groups were very similar in years of education, age of onset of their illness, history of other psychiatric co-morbidities, and treatment received. DISCUSSION: The high percentage of psychosis in the BP group (97.6%) may largely explain the similarities found between groups in their clinical characteristics. CONCLUSION: The differences in social and functional decline support the original dichotomy described by Kraepelin based on chronicity and periodicity between these two psychotic disorders.

Heritability of age of onset of psychosis in schizophrenia.

Schizophrenia is a genetically complex illness with heterogeneous clinical presentation, including variable age of onset. In this study, the heritability, or proportion of variation in age of onset of psychotic symptoms due to genetic factors, was estimated using a maximum likelihood method. The subjects were 717 members of families with more than one member affected with schizophrenia from Mexican and Central American populations. Age of onset of psychosis was determined by best-estimate consensus diagnosis based on the Diagnostic Interview for Genetic Studies, Family Interview for Genetic Studies, and each subject's medical records. Mean age of onset was 21.44 years (SD 8.07); 20.55 years for males (SD 6.90), and 22.67 for females (SD 9.34). Variance components were estimated using a polygenic model in the SOLAR software package. The sex of the participant was a significant covariate (P = 0.010) accounting for 0.02 of the total variance in age of onset. The heritability of age of onset of psychosis was 0.33 (SE = 0.09; P = 0.00004). These findings suggest that genetic factors significantly contribute to the age of onset of psychotic symptoms in individuals with schizophrenia and that sex influences this trait as well.

APOE-epsilon3 and APOE-219G haplotypes increase the risk for schizophrenia in sibling pairs.

To investigate the role of the apolipoprotein E (APOE) gene in schizophrenia, the authors analyzed 60 families with this mental disorder. An association in the presence of linkage test (APL) and haplotypes analysis were undertaken using the APL v1.1 software. A global allelic transmitted was significant for APOE-epsilon3 (chi(2)=6.24, p=0.01); this allele is mainly carried by female patients (chi(2)=8.33, p=0.003), whereas APOE-219G is preferentially transmitted in males (p=0.02). Furthermore, our results show that haplotypes APOE-epsilon3/APOE-219G are associated with schizophrenia (chi(2)=11.61, p=0.01). These results provide evidence that the APOE gene may play a significant role in the etiology of schizophrenia in the Mexican population.

Diagnosis of schizophrenia in latino populations: a comparison of direct interview and consensus based multi-source methods.

We determined the rates of agreement between diagnoses, using the Diagnostic Interview for Genetic Studies (DIGS) and diagnoses arrived at, using additional sources of information, to establish whether there are differences in agreement between direct interview diagnoses at US and non-US sites in comparison best estimate consensus process and to identify diagnoses that could increase diagnostic error when only the DIGS is used. DIGS diagnoses were compared with consensus diagnoses that used the same DIGS interview, plus Family Interview for Genetic Studies (FIGS) and review of medical records in 342 psychotic subjects. We found similar numbers of subjects diagnosed with schizophrenia (225 by direct interview, and 232 by consensus process). The majority of those "misdiagnosed" by direct interview had mood disorder by the consensus. Over 10% of the total subjects diagnosed by direct interview as not meeting criteria for schizophrenia had schizophrenia by consensus. There were no statistically significant differences between countries (US vs. non-US sites) in the agreement rate between direct interview diagnosis and consensus diagnosis. In conclusion, a final best-estimate process is essential to make diagnostic distinctions and to reduce diagnostic misclassifications for both research studies and in clinical practice.

A schizophrenia gene locus on chromosome 17q21 in a new set of families of Mexican and central american ancestry: evidence from the NIMH Genetics of schizophrenia in latino populations study.

OBJECTIVE: The present study investigated a new set of families of Latin American ancestry in order to detect the location of genes predisposing to schizophrenia and related psychotic disorders. METHOD: A genome-wide scan was performed for 175 newly recruited families with at least two siblings suffering from a psychotic disorder. Best-estimate consensus procedures were used to arrive at diagnoses, and nonparametric allele-sharing statistics were calculated to detect linkage. RESULTS: Genome-wide significant evidence for linkage for the phenotype of DSM-IV schizophrenia or schizoaffective disorder was found in a region on chromosome 17q21 (lod score, 3.33). A region on chromosome 15q22-23 showed suggestive evidence of linkage with this same phenotype (lod score, 2.11). Analyses using a broader model (any psychosis) yielded evidence of suggestive linkage for the 17q21 region only, and no region achieved genome-wide significance of linkage. CONCLUSIONS: The new set of 175 families of Mexican and Central American ancestry delineates two new loci likely to harbor predisposition genes for schizophrenia and schizoaffective disorder. The region with the strongest support for linkage in this sample, 17q21, has been implicated in meta-analyses of schizophrenia genome screens, but the authors found no previous reports of it as a locus for schizophrenia in specific population- or family-based studies, and it may represent the location of a schizophrenia predisposition gene (or genes) of special relevance in Mexican and Central American populations.