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Biomedical subjects

Patrick F Sullivan

Publications and source records attributed to Patrick F Sullivan.

At least 19 recordsLinked to original sources

Functional Annotation of the Major Histocompatibility Complex Locus.

The human major histocompatibility complex (MHC) locus has the greatest density of disease-associations in the human genome, including links to over 100 polygenic disorders. Its complex haplotype structure, rich gene density, and high degree of linkage disequilibrium combine to make deciphering the gene regulatory logic of the MHC locus extremely challenging. Employing complementary high-throughput CRISPR interference (CRISPRi) and activation (CRISPRa) epigenetic screens coupled with single-cell transcriptome profiling across three distinct human cell types, we identified hundreds of new connections between cis -regulatory elements (CREs) and their target genes in this locus. These CRE-gene links are largely cell type-specific and act as enhancers. Additionally, some CREs have complex features, including harboring both active and repressive histone marks, lacking chromatin accessibility, targeting multiple genes, or acting as silencers. Computational methods fail to predict a majority of these CRE-gene connections. These findings emphasize the potential for functional perturbation experiments to dissect complex loci and reveal shared and cell type-specific regulatory mechanisms relevant to genomics of complex diseases. Collectively, this study provides a unique resource for understanding the complex regulatory landscape within the MHC locus and supports the need for creating new models that encompass CRE-gene interactions, cell type-specific gene expression, and disease genetics in the noncoding genome.

Journal Article↗

Associations of Genetic Liability to Six Psychiatric Disorders With Cardiometabolic Diseases.

IMPORTANCE: Individuals with psychiatric disorders have increased risk of cardiometabolic diseases (CMDs). Evaluating how psychiatric genetic liability relates to CMD may clarify mechanisms. OBJECTIVE: Identify genetic overlap between psychiatric disorders and CMDs independent of cross-disorder pleiotropy, BMI, and smoking. DESIGN SETTING AND PARTICIPANTS: Three Northern European cohorts (the Swedish Twin Registry, the Estonian Biobank, and the Norwegian Mother, Father and Child Cohort Study [MoBa]) totaling 355,159 individuals. Associations with CMDs were estimated as adjusted odds ratios (AORs) from logistic models mutually adjusted for all psychiatric PRSs and in models additionally adjusting for body mass index (BMI) and smoking. Cohort-specific AORs were pooled by inverse-variance weighting. MAIN OUTCOMES AND MEASURES: Exposures were PRSs for attention-deficit/hyperactivity disorder (ADHD), major depressive disorder (MDD), anxiety disorder, posttraumatic stress disorder (PTSD), bipolar disorder, and schizophrenia. Outcomes were diagnoses of CMDs (hyperlipidemia, obesity, type 2 diabetes, hypertensive diseases, arteriosclerosis, ischemic heart disease, heart failure, thromboembolic disease, cerebrovascular disease, and arrhythmias), ascertained from electronic health records. RESULTS: The MDD PRS was associated with increased risk of all CMDs across analyses (AORs ranged from 1.13 [95% CI, 1.10-1.15] for heart failure to 1.02 [95% CI, 1.00-1.05] for arrhythmias). The ADHD PRS was associated with increased risk of all CMDs (AOR ranged from 1.11 [95% CI, 1.09-1.12] for obesity to 1.02 [95% CI, 1.01-1.03] for hyperlipidemia), however associations where attenuated when adjusting for BMI and smoking (lifestyle adjusted AOR for obesity: 1.03 [95% CI, 1.02-1.05]). When not mutually adjusting for all psychiatric PRSs, anxiety disorder and PTSD PRSs were associated with all CMDs; these associations diminished after adjustment. The bipolar and schizophrenia PRSs were inversely associated with most CMDs (AOR for schizophrenia PRS and obesity, 0.93 [95% CI, 0.92-0.94]). CONCLUSIONS AND RELEVANCE: Associations between psychiatric PRSs and CMDs diverged: ADHD, MDD, anxiety disorder, and PTSD PRSs were positively associated with CMDs, whereas bipolar and schizophrenia PRSs were inversely associated. Genetic liability to MDD showed robust associations with CMDs independent of cross-disorder pleiotropy, BMI, and smoking status, whereas associations between the ADHD PRS and CMDs were largely attenuated after adjustment for BMI and smoking.

Journal Article↗

Genome-wide copy number variation association study in anorexia nervosa.

This study represents the first large-scale investigation of rare (<1% population frequency) copy number variants (CNVs) in anorexia nervosa (AN). Large, rare CNVs are reported to be causally associated with anthropometric traits, neurodevelopmental disorders, and schizophrenia, yet their role in the genetic basis of AN is unclear. Using genome-wide association study (GWAS) array data from the Anorexia Nervosa Genetics Initiative (ANGI), which included 7414 AN case and 5044 controls, we investigated the association of 67 well-established syndromic CNVs and 178 pleiotropic disease-risk dosage-sensitive CNVs with AN. To identify novel CNV regions (CNVRs) that increase the risk of AN, we conducted genome-wide association studies with a focus on rare CNV-breakpoints (CNV-GWAS). We found no net enrichment of rare CNVs, either deletions or duplications, in AN, and none of the well-established syndromic or pleiotropic CNVs had a significant association with AN status. However, the CNV-GWAS found 21 nominally associated CNVRs that contribute to AN risk, covering protein-coding genes implicated in synaptic function, metabolic/mitochondrial factors, and lipid characteristics, like the CD36 (7q21.11) gene, which transports long-chain fatty acids into cells. CNVRs intersecting genes previously related to neurodevelopmental traits include deletions of NRXN1 intron 5 (2p16.3), IMMP2L (7q31.1), and PTPRD (9p23). Overall, given that our study is well powered to detect the CNV burden level reported for schizophrenia, we can conclude that rare CNVs have a limited role in the etiology of AN, as reported for bipolar disorder. Our nominal associations for the 21 discovered CNVRs are consistent with AN being a metabo-psychiatric trait, as demonstrated by the common genetic architecture of AN, and we provide association results to allow for replication in future research.

Humans↗

NCAM1 and neurocognition in schizophrenia.

BACKGROUND: Alterations in neurocognition may be fundamental to schizophrenia and may be endophenotypes. Neural cell adhesion molecule 1 (NCAM1, aliases NCAM and CD56) may be a candidate gene for schizophrenia or for neurocognition in schizophrenia as supported by linkage and functional findings. METHODS: Subjects were 641 patients with schizophrenia who participated in the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) clinical trial. Neurocognition was assessed at study baseline. Nine NCAM1 single nucleotide polymorphisms (SNPs) were blindly genotyped. Analysis of covariance was used to test for single SNP associations and haplotype regression for multilocus associations. RESULTS: As there were suggestions of population stratification, all analyses were conducted stratified by inferred ancestry. In the "Europe only" stratum, there were nominally significant associations with five contiguous SNPs (rs1943620, rs1836796, rs1821693, rs686050, rs584427) with the strongest association at rs1836796 (p = .007). Via permutation testing, the probability of obtaining five consecutive statistically significant SNPs with p-values <or= .05 was p = .0044. These results were robust to examination of model assumptions. Haplotype analyses did not identify significant haplotype associations. CONCLUSIONS: Although it is essential to see if these findings replicate in additional samples, we suggest that NCAM1 deserves further scrutiny for its relevance to clinical and etiological aspects of schizophrenia.

Adult↗

Variation in leaf physiology of Salix arctica within and across ecosystems in the High Arctic: test of a dual isotope (Delta13C and Delta18O) conceptual model.

Leaf carbon isotope discrimination (Delta(13)C) varies with the balance between net photosynthesis (A) and stomatal conductance (g ( s )). Inferences that can be made with Delta(13)C are limited, as changes could reflect variation in A and/or g ( s ). Investigators have suggested that leaf delta(18)O enrichment above source water (Delta(18)O) may enable differentiation between sources of variation in Delta(13)C, as leaf Delta(18)O varies with transpiration rate (E), which is closely correlated with g ( s ) when leaves experience similar leaf to air vapor pressure differences. We examined leaf gas exchange of Salix arctica at eight sites with similar air temperatures and relative humidities but divergent soil temperatures and soil water contents near Pituffik, Greenland (76 degrees N, 38 degrees W). We found negative correlations at the site level between g ( s ) and Delta(18)O in bulk leaf tissue (r (2) = 0.62, slope = -17.9 per thousand/mol H(2)O m(-2) s(-1), P = 0.02) and leaf alpha-cellulose (r (2) = 0.83, slope = -11.5 per thousand mol H(2)O m(-2) s(-1), P < 0.01), consistent with the notion that leaf water enrichment declines with increasing E. We also found negative correlations at the site-level between intrinsic water-use efficiency (iWUE) and Delta(13)C in bulk leaf tissue (r (2) = 0.65, slope = -0.08 per thousand/mumol CO(2) /mol H(2)O, P = 0.02) and leaf alpha-cellulose (r (2) = 0.50, slope = -0.05 per thousand/[mumol CO(2) /mol H(2)O], P = 0.05). When increasing Delta(13)C was driven by increasing g ( s ) alone, we found negative slopes between Delta(13)C and Delta(18)O for bulk leaf tissue (-0.664) and leaf alpha-cellulose (-1.135). When both g ( s ) and A (max) increased, we found steeper negative slopes between Delta(13)C and Delta(18)O for bulk leaf tissue (-2.307) and leaf alpha-cellulose (-1.296). Our results suggest that the dual isotope approach is capable of revealing the qualitative contributions of g ( s ) and A (max) to Delta(13)C at the site level. In our study, bulk leaf tissue was a better medium than leaf alpha-cellulose for application of the dual isotope approach.

Arctic Regions↗

Haplotypes spanning SPEC2, PDZ-GEF2 and ACSL6 genes are associated with schizophrenia.

Chromosome 5q22-33 is a region where studies have repeatedly found evidence for linkage to schizophrenia. In this report, we took a stepwise approach to systematically map this region in the Irish Study of High Density Schizophrenia Families (ISHDSF, 267 families, 1337 subjects) sample. We typed 289 SNPs in the critical interval of 8 million basepairs and found a 758 kb interval coding for the SPEC2/PDZ-GEF2/ACSL6 genes to be associated with the disease. Using sex and genotype-conditioned transmission disequilibrium test analyses, we found that 19 of the 24 typed markers were associated with the disease and the associations were sex-specific. We replicated these findings with an Irish case-control sample (657 cases and 414 controls), an Irish parent-proband trio sample (187 families, 564 subjects), a German nuclear family sample (211 families, 751 subjects) and a Pittsburgh nuclear family sample (247 families, 729 subjects). In all four samples, we replicated the sex-specific associations at the levels of both individual markers and haplotypes using sex- and genotype-conditioned analyses. Three risk haplotypes were identified in the five samples, and each haplotype was found in at least two samples. Consistent with the discovery of multiple estrogen-response elements in this region, our data showed that the impact of these haplotypes on risk for schizophrenia differed in males and females. From these data, we concluded that haplotypes underlying the SPEC2/PDZ-GEF2/ACSL6 region are associated with schizophrenia. However, due to the extended high LD in this region, we were unable to distinguish whether the association signals came from one or more of these genes.

Chromosomes, Human, Pair 5↗

[Genetics in eating disorders: extending the boundaries of research].

OBJECTIVE: To review the recent literature relevant to genetic research in eating disorders and to discuss unique issues which are crucial for the development of a genetic research project in eating disorders in Brazil. METHOD: A computer literature review was conducted in the Medline database between 1984 and may 2005 with the search terms "eating disorders", "anorexia nervosa", "bulimia nervosa", "binge eating disorder", "family", "twin" and "molecular genetic" studies. RESULTS: Current research findings suggest a substantial influence of genetic factors on the liability to anorexia nervosa and bulimia nervosa. Genetic research with admixed populations should take into consideration sample size, density of genotyping and population stratification. Through admixture mapping it is possible to study the genetic structure of admixed human populations to localize genes that underlie ethnic variation in diseases or traits of interest. CONCLUSIONS: The development of a major collaborative genetics initiative of eating disorders in Brazil and South America would represent a realistic possibility of studying the genetics of eating disorders in the context of inter ethnic groups, and also integrate a new perspective on the biological etiology of eating disorders.

Anorexia Nervosa↗

Recurrence risks for schizophrenia in a Swedish national cohort.

OBJECTIVE: Recurrence risk estimates for schizophrenia are fundamental to our understanding of this complex disease. Widely cited estimates are from small/older samples. If these estimates are biased upwards, then the rationale for molecular genetic studies of schizophrenia may not be as solid. METHOD: We created a population-based, Swedish national cohort by linking two Swedish national registers into a relational database (the Swedish Hospital Discharge Register and the Multi-Generation Register). Affection was defined as the lifetime presence of at least two in-patient hospitalizations with a core schizophrenia diagnosis. RESULTS: Merging the Swedish national registers created a population-based cohort of 7,739,202 individuals of known parentage. The lifetime prevalence of the narrow definition of schizophrenia was 0.407% and we estimated that one in every 79 extended Swedish families had been impacted by schizophrenia. The proportion of affected families with multiple affected members was 3.81%. Recurrence risk estimates for all relative types were strikingly similar to those reported in smaller and older studies. For example, we estimated lambda(sibs) at 8.55 [95% confidence interval (CI) 7.86-9.57] compared with a literature estimate of 8.6. CONCLUSIONS: In the largest and most comprehensive sample yet studied, we confirm the accepted estimates of recurrence risks for schizophrenia, and provide more accurate estimates of recurrence risks of schizophrenia in relatives, an estimate of the familial impact of schizophrenia, and the multiplex proportion (essential for gauging the generalizability of findings from multiplex pedigrees). These data may be valuable for planning and interpreting genetic studies of schizophrenia.

Adolescent↗

Extensions to the modeling of initiation and progression: applications to substance use and abuse.

Twin data can provide valuable insight into the relationship between the stages of phenomena such as disease or substance abuse. Initiation of substance use may be caused by factors that are the same as, partially shared with, or completely independent of those that cause progression from use to abuse. Comparison of rates of progression among the cotwins of twins who do vs. do not initiate provides indirect information about the relationship between initiation and progression. Existing models for this relationship have been difficult to extend because they are usually expressed in terms of explicit integrals. In this paper, the problem is overcome by regarding the analysis of twin data on initiation and progression as a special case of missing data, in which individuals who do not initiate are regarded as having missing data on progression measures. Using the general framework for the analysis of ordinal data with missing values available in Mx makes extensions that include other variables much easier. The effects of continuous covariates such as age on initiation and progression becomes simple. Also facilitated are the examination of initiation and progression in two or more substances, and transition models with two or more steps. The methods are illustrated with data on the effects of cohort on liability to cannabis use and abuse, bivariate analysis of tobacco use and dependence and cannabis use and abuse, and the relationships between initiation of smoking, regular smoking and nicotine dependence. Other suitable applications include the relationship between symptoms and diagnosis, such as fears and the progression to phobia.

Age Factors↗

A dopamine transporter polymorphism is a risk factor for borderline personality disorder in depressed patients.

BACKGROUND: Borderline personality disorder (BPD) is often co-morbid with major depression and may complicate its treatment. We were interested in differences in genetic and developmental risk factors between depressed patients with or without a co-morbid BPD. METHOD: Out-patients with major depressive disorder were recruited for two treatment trials. Assessment of depressed patients included the assessment of personality disorders, developmental risk factors and DNA samples for genetic analyses. RESULTS: In each study there was a significant association between the 9-repeat allele of the dopamine transporter (DAT1) and BPD, with odds ratios (OR) > 3 and p < or = 0.02. This association remained significant when developmental risk factors for BPD (childhood abuse and neglect and borderline temperament) were also included in the analyses. The OR was even larger in the depressed patients aged > or = 35 years (OR 9.31, p = 0.005). CONCLUSION: This replicated association in depressed patients between the 9-repeat allele of DAT1 and BPD may provide clues to understanding the neurobiology of BPD. The finding that the association is larger in the older depressed patients, suggests that the 9-repeat allele may be associated with a poorer prognosis BPD, rather than a young adult limited variant of BPD.

Adult↗

Evaluating the comparability of gene expression in blood and brain.

The availability of an accessible tissue whose gene expression profile is similar to more inaccessible CNS tissues has the potential to advance research in neuropsychiatric disorders. We conducted secondary data analysis of transcriptional profiling of 79 human tissues for 33,698 genes using the Affymetrix U133A microarray augmented with a custom microarray (Affymetrix GNF1H), which were produced by the Genomics Institute of the Novartis Research Foundation (http://symatlas.gnf.org). Our analyses suggested that: (a) on a transcriptome level, whole blood shares significant gene expression similarities with multiple CNS tissues; (b) the median non-parametric correlation between transcripts present in both whole blood and CNS was around 0.5; (c) this correlation of 0.5 was intermediate relative to all tissues in the Novartis data set--less than for the maximum achievable value of 0.85, less than a set of immune tissues (0.64), comparable to a heterogeneous set of somatic tissues (0.57) but greater than muscle (0.48) and peripheral nervous system tissues (0.36); (d) about half of a set of candidate genes relevant to schizophrenia were expressed in both whole blood and prefrontal cortex; and (e) the expression levels of many classes of biologically relevant processes were not significantly different between whole blood and prefrontal cortex. These analyses suggest that gene expression in whole blood is neither perfectly correlated and useful nor perfectly uncorrelated and useless with gene expression in multiple brain tissues. This suggests that the cautious and thoughtful use of peripheral gene expression may be a useful surrogate for gene expression in the CNS when it has been determined that the relevant gene is expressed in both.

Brain↗

TAMAL: an integrated approach to choosing SNPs for genetic studies of human complex traits.

UNLABELLED: Investigators conducting studies of the molecular genetics of complex traits in humans often need rationally to select a set of single nucleotide polymorphisms (SNPs) from the hundreds or thousands available for a candidate gene. Accomplishing this requires integration of genomic data from distributed databases and is both time-consuming and error-prone. We developed the TAMAL (Technology And Money Are Limiting) web site to help identify promising SNPs for further investigation. For a given list of genes, TAMAL identifies SNPs that meet user-specified criteria (e.g. haplotype tagging SNPs or SNP predicted to lead to amino acid changes) from current versions of online resources (i.e. HapMap, Perlegen, Affymetrix, dbSNP and the UCSC genome browser). AVAILABILITY: TAMAL is a platform independent web-based application available free of charge at http://neoref.ils.unc.edu/tamal. SUPPLEMENTARY INFORMATION: http://neoref.ils.unc.edu/tamal/.

Chromosome Mapping↗

Premorbid predictors of chronic fatigue.

CONTEXT: Chronic fatigue syndrome is a disabling problem characterized by persistent fatigue lasting at least 6 months with a number of ancillary symptoms. Although the etiology of chronic fatiguing illness is unknown, some evidence suggests that stress may confer increased risk for development of the disorder. Moreover, subjects with chronic fatiguing illness may have distinctive personality traits, although this finding could reflect confounding by other mechanisms. OBJECTIVE: To assess the prospective association of premorbid self-reported stress and personality with chronic fatigue-like illness. DESIGN: Prospective nested case-control study in a population-based sample. SETTING: General community. PARTICIPANTS: From the Swedish Twin Registry, 19,192 twins born between January 1, 1935, and December 31, 1958. MAIN OUTCOME MEASURES: Information about current chronic fatiguing illnesses was obtained from computer-assisted telephone interviews conducted between 1998 and 2002. Self-reported stress (based on a single question) and personality scales (emotional instability and extraversion in the Eysenck Personality Inventory) were measured from 1972 to 1973 by a mailed questionnaire. Relative risks were estimated with case-control analyses (matched for age and sex) and co-twin control analyses (comparing discordant pairs). RESULTS: Higher emotional instability and self-reported stress in the premorbid period were associated with higher risk for chronic fatigue-like illness in matched case-control analyses (odds ratios, 1.72 and 1.64, respectively). In co-twin control analyses, relative risk of emotional instability decreased to 1.02 whereas that of stress increased considerably to 5.81. There was no association between extraversion and fatigue. CONCLUSIONS: Elevated premorbid stress is a significant risk factor for chronic fatigue-like illness, the effect of which may be buffered by genetic influences. Emotional instability assessed 25 years earlier is associated with chronic fatigue through genetic mechanisms contributing to both personality style and expression of the disorder. These findings suggest plausible mechanisms for chronic fatiguing illness.

Affective Symptoms↗

Prevalence, heritability, and prospective risk factors for anorexia nervosa.

CONTEXT: Anorexia nervosa (AN) is a serious mental illness with marked morbidity and mortality. OBJECTIVE: To explore the prevalence, heritability, and prospectively assessed risk factors for AN in a large population-based cohort of Swedish twins. DESIGN: During a 4-year period ending in 2002, all living, contactable, interviewable, and consenting twins in the Swedish Twin Registry (N = 31 406) born between January 1, 1935, and December 31, 1958, underwent screening for a range of disorders, including AN. Information collected systematically in 1972 to 1973, before the onset of AN, was used to examine prospective risk factors for AN. SETTING: Population-based sample of twins in Sweden. PARTICIPANTS: Cases of AN were identified as those individuals who met full DSM-IV criteria by means of clinical interview of the Swedish Twin Registry, who had a hospital discharge diagnosis of AN, or who had a cause-of-death certificate including an AN diagnosis. RESULTS: The overall prevalence of AN was 1.20% and 0.29% for female and male participants, respectively. The prevalence of AN in both sexes was greater among those born after 1945. Individuals with lifetime AN reported lower body mass index, greater physical activity, and better health satisfaction than those without lifetime AN. Anorexia nervosa was inversely associated with the development of overweight (odds ratio, 0.29; 95% confidence interval [CI], 0.16-0.54 [P<.001]). The heritability of narrowly defined DSM-IV AN (additive genetic effects) was estimated to be a(2) = 0.56 (95% CI, 0.00-0.87), with the remaining variance attributable to shared environment (c(2) = 0.05; 95% CI, 0.00-0.64) and unique environment (e(2) = 0.38; 95% CI, 0.13-0.84). Neuroticism measured about 3 decades before the diagnostic assessment was significantly associated with the development of later AN (odds ratio, 1.62; 95% CI, 1.27-2.05 [P<.001]). CONCLUSIONS: The prevalence of AN was higher in both male and female participants born after 1945. Individuals who survive AN and who no longer have body mass indexes in the AN range appear to be at lower risk for the development of overweight. Prospectively assessed neuroticism was associated with the subsequent development of AN, the liability to which is under considerable genetic influence.

Anorexia Nervosa↗

Importance of genetic influences on chronic widespread pain.

OBJECTIVE: To estimate the relative importance of genetic and environmental factors in chronic widespread pain, and to assess whether there are sex differences in the type or magnitude of these influences. METHODS: Data were collected from a national sample of twins > or = 42 years of age, all of whom were participants in the Swedish Twin Registry. The presence of chronic widespread pain was assessed via computer-assisted telephone interviews, which were conducted between 1998 and 2002, using the American College of Rheumatology criteria for fibromyalgia. No clinical examinations were performed. In preliminary analyses, probandwise concordance rates and tetrachoric correlations were calculated. Structural equation modeling was then performed to estimate additive genetic, shared environmental, and nonshared environmental sources of variability in susceptibility for the development of chronic widespread pain. RESULTS: Of 61,355 eligible twins, 44,897 individuals (73.2%) responded to the interview. Both members of 15,950 pairs responded to the items regarding pain symptoms; of these pairs, 4,170 were monozygotic, 5,881 were same-sex dizygotic, and 5,755 were opposite-sex dizygotic. The prevalence of chronic widespread pain was 4.1%, and the ratio of women to men was 3.3 to 1. Probandwise concordance rates and tetrachoric correlations suggested modest genetic influences for both women and men. Genetic and shared environmental influences explained approximately half of the total variance, with no indication of sex differences in either the type or magnitude of these influences. CONCLUSION: Individual differences in the likelihood of developing chronic widespread pain reflect modest genetic influences. There are no significant sex differences in the type or expression of the genes responsible for chronic widespread pain or in the magnitude of the relative importance of these influences on chronic widespread pain.

Chronic Disease↗

Genetic, developmental and personality correlates of self-mutilation in depressed patients.

OBJECTIVE: To examine whether the T allele of G protein beta3 (GNbeta3) is associated with self-mutilation in depressed patients. METHOD: A history of self-mutilation was systematically inquired about when recruiting depressed patients for a long-term treatment trial. Risk factors such as borderline personality disorder and childhood abuse experiences were systematically assessed, and patients were genotyped for polymorphisms of GNbeta3. RESULTS: The T allele of GNbeta3, borderline personality disorder and childhood sexual abuse were all significantly associated with self-mutilation in depressed patients. These associations were significant in both univariate and multivariate analyses, and as predicted were stronger in young depressed patients than in depressed patients of all ages. CONCLUSIONS: If the association between the T allele of GNbeta3 and self-mutilation can be replicated, this may provide clues to understanding the neurobiology of self-mutilation.

Adolescent↗

Cigarettes and oral snuff use in Sweden: Prevalence and transitions.

AIMS: To investigate the prevalence and patterns of transitions between cigarette and snus use. DESIGN: Cross-sectional study within the population-based Swedish Twin Registry. SETTING AND PARTICIPANTS: A total of 31 213 male and female twins 42-64 years old. MEASUREMENTS: Age-adjusted prevalence odds ratios (POR) and 95% confidence intervals (CIs) described the association between gender and tobacco use, while Kaplan-Meier survival methods produced cumulative incidence curves of age at onset of tobacco use. Life-time tobacco use histories were constructed using ages at onset of tobacco use and current tobacco use status. FINDINGS: Although more males reported ever smoking (64.4%) than females (61.7%), more males were former smokers (POR: 1.33, 95% CI: 1.27-1.39). Males were far more likely to use snus than females (POR: 18.0, 95% CI: 16.17-20.04). Age at onset of cigarette smoking occurred almost entirely before age 25, while the age at onset of snus use among males occurred over a longer time period. Most men began using cigarettes first, nearly one-third of whom switched to using cigarettes and snus in combination. While 30.6% of these combined users quit tobacco completely, only 7.4% quit snus and currently use cigarettes, while 47.7% quit cigarettes and currently use snus. CONCLUSIONS: Current cigarette smoking is more prevalent among Swedish women than men, while snus use is more prevalent among men. Among men who reported using both cigarettes and snus during their life-time, it was more common to quit cigarettes and currently use snus than to quit snus and currently use cigarettes. Once snus use was initiated, more men continued using snus rather than quit tobacco completely.

Adult↗

Identification of susceptibility loci for alcohol-related traits in the Irish Affected Sib Pair Study of Alcohol Dependence.

BACKGROUND: Alcoholism is a phenotypically and probably genetically heterogeneous condition. Thus, one strategy for finding genes influencing liability to alcoholism is to study the components of alcoholism, which may be more directly related to the underlying pathophysiology than is clinical diagnosis. The goal of this study was to identify genomic regions containing susceptibility loci for alcohol-related traits. METHODS: A 4-cM dense whole-genome linkage study was conducted in the Irish Affected Sib Pair Study of Alcohol Dependence. Probands, affected siblings, and parents were evaluated by structured interview. Variance component linkage analysis was applied to data from 485 families for 5 measures: initial sensitivity and tolerance (based on scales from the self-report of the effects of ethanol; maximum drinks within 24 hours, an empirically derived factor score based on withdrawal symptoms, and age at onset of alcohol dependence. RESULTS: Evidence for linkage (p<0.005) was found on 9 chromosomes. For age at onset, 2 regions were found on chromosome 9 (highest Lod=2.3, p=0.0005). For initial level of response to alcohol, suggestive regions were on chromosomes 1 and 11 (highest Lod=2.9, p=0.0001 on chromosome 11), while those for tolerance signals were on chromosomes 1, 6, and 22. Maximum drinking was associated with regions on chromosomes 12 and 18. For withdrawal symptoms, the highest peak was on chromosome 2 (Lod=2.2, p=0.0007). CONCLUSIONS: Using quantitative measures of components of alcohol dependence, we identified several regions of the genome that may contain susceptibility loci for specific alcohol-related traits and merit additional study.

Adult↗