P C Sham

Summary

Affiliation: King's College London
Country: UK

Publications

  1. pmc Power of linkage versus association analysis of quantitative traits, by use of variance-components models, for sibship data
    P C Sham
    Social, Genetic and Developmental Psychiatry Research Centre, Institute of Psychiatry, London SE5 8AF, United Kingdom
    Am J Hum Genet 66:1616-30. 2000
  2. ncbi request reprint Statistical methods in psychiatric genetics
    P C Sham
    Department of Psychological Medicine, Institute of Psychiatry, London, UK
    Stat Methods Med Res 7:279-300. 1998
  3. ncbi request reprint GENESiS: creating a composite index of the vulnerability to anxiety and depression in a community-based sample of siblings
    P C Sham
    Social, Genetic and Developmental Psychiatry Research Centre, London, UK
    Twin Res 3:316-22. 2000
  4. ncbi request reprint Optimal weighting scheme for affected sib-pair analysis of sibship data
    P C Sham
    Department of Psychological Medicine, Institute of Psychiatry, London, England
    Ann Hum Genet 61:61-9. 1997
  5. pmc Power comparison of parametric and nonparametric linkage tests in small pedigrees
    P C Sham
    Departments of Psychiatry and Biostatistics and Computing, Institute of Psychiatry, London SE5 8AF, United Kingdom
    Am J Hum Genet 66:1661-8. 2000
  6. ncbi request reprint Genetic Power Calculator: design of linkage and association genetic mapping studies of complex traits
    S Purcell
    Social, Genetics and Developmental Psychiatry Research Centre, Institute of Psychiatry, King s College London, De Crespigny Park, UK
    Bioinformatics 19:149-50. 2003
  7. ncbi request reprint Heritability estimates for psychotic disorders: the Maudsley twin psychosis series
    A G Cardno
    Department of Psychological Medicine, University of Wales College of Medicine, Cardiff, United Kingdom
    Arch Gen Psychiatry 56:162-8. 1999
  8. ncbi request reprint Evidence for association between polymorphisms in the promoter and coding regions of the 5-HT2A receptor gene and response to clozapine
    M J Arranz
    Department of Psychological Medicine, Institute of Psychiatry, Denmark Hill, London, UK
    Mol Psychiatry 3:61-6. 1998
  9. ncbi request reprint Haplotype association analysis of discrete and continuous traits using mixture of regression models
    P C Sham
    Social, Genetic, and Developmental Psychiatry Research Centre, Institute of Psychiatry, P O 080, King s College London, De Crespigny Park, London SE5 8AF, United Kingdom
    Behav Genet 34:207-14. 2004
  10. ncbi request reprint Use of an artificial neural network to detect association between a disease and multiple marker genotypes
    D Curtis
    Joint Academic Department of Psychological Medicine, St Bartholomew s and Royal London School of Medicine and Dentistry, London, UK
    Ann Hum Genet 65:95-107. 2001

Collaborators

Detail Information

Publications52

  1. pmc Power of linkage versus association analysis of quantitative traits, by use of variance-components models, for sibship data
    P C Sham
    Social, Genetic and Developmental Psychiatry Research Centre, Institute of Psychiatry, London SE5 8AF, United Kingdom
    Am J Hum Genet 66:1616-30. 2000
    ..We also describe both how the power of linkage is attenuated by incomplete linkage and incomplete marker information and how the power of association is attenuated by incomplete linkage disequilibrium...
  2. ncbi request reprint Statistical methods in psychiatric genetics
    P C Sham
    Department of Psychological Medicine, Institute of Psychiatry, London, UK
    Stat Methods Med Res 7:279-300. 1998
    ....
  3. ncbi request reprint GENESiS: creating a composite index of the vulnerability to anxiety and depression in a community-based sample of siblings
    P C Sham
    Social, Genetic and Developmental Psychiatry Research Centre, London, UK
    Twin Res 3:316-22. 2000
    ..This index, which has a sib correlation of 0.22, will be used as a quantitative phenotype in the molecular genetic phase of GENESiS...
  4. ncbi request reprint Optimal weighting scheme for affected sib-pair analysis of sibship data
    P C Sham
    Department of Psychological Medicine, Institute of Psychiatry, London, England
    Ann Hum Genet 61:61-9. 1997
    ..A corollary is that, in affected sib-pair analysis, the 'informativeness' of a sibship is more nearly proportional to the number of affected sib-pairs than to the number of affected siblings, up to about five affected siblings...
  5. pmc Power comparison of parametric and nonparametric linkage tests in small pedigrees
    P C Sham
    Departments of Psychiatry and Biostatistics and Computing, Institute of Psychiatry, London SE5 8AF, United Kingdom
    Am J Hum Genet 66:1661-8. 2000
    ..The results also suggest that both parametric and nonparametric methods are suitable for linkage analysis of complex disorders in small pedigrees. However, whether these results apply to large pedigrees remains to be answered...
  6. ncbi request reprint Genetic Power Calculator: design of linkage and association genetic mapping studies of complex traits
    S Purcell
    Social, Genetics and Developmental Psychiatry Research Centre, Institute of Psychiatry, King s College London, De Crespigny Park, UK
    Bioinformatics 19:149-50. 2003
    ..A website for performing power calculations for the design of linkage and association genetic mapping studies of complex traits...
  7. ncbi request reprint Heritability estimates for psychotic disorders: the Maudsley twin psychosis series
    A G Cardno
    Department of Psychological Medicine, University of Wales College of Medicine, Cardiff, United Kingdom
    Arch Gen Psychiatry 56:162-8. 1999
    ....
  8. ncbi request reprint Evidence for association between polymorphisms in the promoter and coding regions of the 5-HT2A receptor gene and response to clozapine
    M J Arranz
    Department of Psychological Medicine, Institute of Psychiatry, Denmark Hill, London, UK
    Mol Psychiatry 3:61-6. 1998
    ..These results provide further evidence suggesting that genetic variation at 5-HT2A receptors may influence clozapine response and strengthen the candidacy of these receptors as important therapeutic targets...
  9. ncbi request reprint Haplotype association analysis of discrete and continuous traits using mixture of regression models
    P C Sham
    Social, Genetic, and Developmental Psychiatry Research Centre, Institute of Psychiatry, P O 080, King s College London, De Crespigny Park, London SE5 8AF, United Kingdom
    Behav Genet 34:207-14. 2004
    ..We have implemented this method using the SNPHAP and Mx programs and illustrated its use on published data on idiopathic generalized epilepsy...
  10. ncbi request reprint Use of an artificial neural network to detect association between a disease and multiple marker genotypes
    D Curtis
    Joint Academic Department of Psychological Medicine, St Bartholomew s and Royal London School of Medicine and Dentistry, London, UK
    Ann Hum Genet 65:95-107. 2001
    ..The application of neural networks to such problems shows considerable promise and further work could usefully be directed towards optimising the design and implementation of such networks...
  11. ncbi request reprint Association analysis between dopamine receptor genes and bipolar affective disorder
    T Li
    Department of Psychological Medicine, The Institute of Psychiatry, London, UK
    Psychiatry Res 86:193-201. 1999
    ..We also report a novel, rare one-repeat variant of the DRD4 exon 3 VNTR repeat in Chinese populations, which appears to be absent in Caucasians and is not associated with disease...
  12. ncbi request reprint Transmission disequilibrium analysis of HLA class II DRB1, DQA1, DQB1 and DPB1 polymorphisms in schizophrenia using family trios from a Han Chinese population
    T Li
    Department of Psychological Medicine, Institute of Psychiatry, SE5 8AF, London, UK
    Schizophr Res 49:73-8. 2001
    ..However, our results are compatible with the view that this region of HLA might contain a susceptibility gene which is in linkage disequilibrium with DRB1 and DQA1 genes...
  13. ncbi request reprint Model-free analysis and permutation tests for allelic associations
    J H Zhao
    Department of Psychological Medicine, Institute of Psychiatry, St Bartholomew s and Royal London School of Medicine and Dentistry, London, UK
    Hum Hered 50:133-9. 2000
    ..A memory-efficient algorithm is developed which enables several highly polymorphic markers to be analysed...
  14. ncbi request reprint Optimal sibship selection for genotyping in quantitative trait locus linkage analysis
    S Purcell
    Social, Genetic and Developmental Research Centre, 111 Denmark Hill, Denmark Hill, London SE5 8AF, UK
    Hum Hered 52:1-13. 2001
    ..In comparison to previous methods of selecting phenotypically extreme sibships for genotyping, the proposed method is considerably more efficient and is robust with regard to the specification of the genetic model...
  15. pmc Equivalence between Haseman-Elston and variance-components linkage analyses for sib pairs
    P C Sham
    Social, Genetic and Developmental Research Centre, Institute of Psychiatry, London, SE5 8AF, England
    Am J Hum Genet 68:1527-32. 2001
    ..We show how this method can be used for both the selection of maximally informative sib pairs for genotyping and the subsequent analysis of such selected samples...
  16. ncbi request reprint Association analysis of monoamine genes with measures of depression and anxiety in a selected community sample of siblings
    M W Nash
    Social, Genetic, and Developmental Psychiatry Centre, Institute of Psychiatry, King s College London, London, United Kingdom
    Am J Med Genet B Neuropsychiatr Genet 135:33-7. 2005
    ..To our knowledge, this is the first study to report an association of the 3' end of TPH1 with continuous measures of depression and anxiety...
  17. ncbi request reprint Variance-Components QTL linkage analysis of selected and non-normal samples: conditioning on trait values
    P C Sham
    Social, Genetic and Developmental Psychiatry Research Center and Department of Psychiatry, Institute of Psychiatry, Denmark Hill, London, United Kingdom
    Genet Epidemiol 19:S22-8. 2000
    ....
  18. ncbi request reprint Analytic power calculation for QTL linkage analysis of small pedigrees
    F V Rijsdijk
    Social, Genetic and Developmental Psychiatry Research Centre, Institute of Psychiatry, London SE5 8AF, UK
    Eur J Hum Genet 9:335-40. 2001
    ..We show that this approximation is sufficiently accurate for practical purposes in small to moderately large pedigrees, and that large sibships are more efficient than other family structures under a range of genetic models...
  19. ncbi request reprint Combining functional and linkage disequilibrium information in the selection of tag SNPs
    P C Sham
    Department of Psychiatry, Institute of Psychiatry, King s College London, UK
    Bioinformatics 23:129-31. 2007
    ..This flexible feature is useful for researchers who wish to prioritize genomic regions or SNPs in an association study. AVAILABILITY: The online WCLUSTAG program is available at http://bioinfo.hku.hk/wclustag/..
  20. ncbi request reprint Life events and depression in a community sample of siblings
    F V Rijsdijk
    Social, Genetic and Developmental Psychiatry Research Centre, Institute of Psychiatry, London
    Psychol Med 31:401-10. 2001
    ..Appropriate modelling of life events in linkage and association analyses should help to identify QTLs for depression and anxiety...
  21. ncbi request reprint Extension of conditional model-free likelihood-based linkage analysis to additive and other models
    D Curtis
    Joint Academic Department of Psychological Medicine, St Bartholomew s and Royal London School of Medicine and Dentistry, Royal London Hospital, Whitechapel, London, UK
    Ann Hum Genet 66:157-67. 2002
    ..Nevertheless, the new method allows researchers greater flexibility in analysing linkage data for diseases in which one or more risk polymorphisms have already been identified...
  22. ncbi request reprint The effect of marker characteristics on the power to detect linkage disequilibrium due to single or multiple ancestral mutations
    P C Sham
    Department of Psychiatry, Institute of Psychiatry, London, UK
    Ann Hum Genet 64:161-9. 2000
    ..They also show that multiple ancestral disease mutations do not necessarily preclude linkage disequilibrium mapping, if highly polymorphic markers or multi-locus haplotypes are used...
  23. ncbi request reprint Brain MRI abnormalities in schizophrenia: same genes or same environment?
    F V Rijsdijk
    Social, Genetic and Developmental Psychiatry Research Centre, Institute of Psychiatry, London, UK
    Psychol Med 35:1399-409. 2005
    ..Bivariate genetic model fitting (adjusted to account for selection) was used to quantify the genetic relationship between schizophrenia and brain volumes and to estimate the heritability of these volumes...
  24. ncbi request reprint A model-fitting implementation of the DeFries-Fulker model for selected twin data
    S Purcell
    Social, Genetic and Developmental Research Centre, Institute of Psychiatry, London SE5 8AF, UK
    Behav Genet 33:271-8. 2003
    ..This more flexible implementation of the DF model allows DZ-O twins to be incorporated in a sex-limitation model. Brief simulation results are presented along with the Mx scripts used...
  25. ncbi request reprint A novel method of two-locus linkage analysis applied to a genome scan for late onset Alzheimer's disease
    D Curtis
    Joint Academic Department of Psychological Medicine, St Bartholomew s and Royal London School of Medicine and Dentistry, London, UK
    Ann Hum Genet 65:473-81. 2001
    ..The results provide support for the existence of additional susceptibility loci linked to D10S1211 and to D12S358...
  26. ncbi request reprint The common genetic liability between schizophrenia and bipolar disorder: a review
    E Bramon
    Division of Psychological Medicine and Social Genetic Developmental Psychiatry Research Centre, Institute of Psychiatry, De Crespigny Park, London SE5 8AF, United Kingdom
    Curr Psychiatry Rep 3:332-7. 2001
    ..Thus, recent evidence increasingly supports a dimensional approach in the understanding of the functional psychoses, and this is expected to have implications for etiologic research and future clinical treatment...
  27. ncbi request reprint Association analysis of polymorphisms in the DRD4 gene and heroin abuse in Chinese subjects
    T Li
    Section of Molecular Genetics, Department of Psychological Medicine, and Social, Genetic, and Developmental Psychiatry Centre, Institute of Psychiatry, De Crespigny Park, Denmark Hill, London, United Kingdom
    Am J Med Genet 96:616-21. 2000
    ..The association we observed between inhalers and the DRD4 polymorphism is difficult to interpret, although it is possible that the association is explained by different levels of novelty seeking between the two subgroups...
  28. ncbi request reprint Scholastic achievement at age 16 and risk of schizophrenia and other psychoses: a national cohort study
    J H MacCabe
    Department of Psychiatry, Institute of Psychiatry, King s College London, London, UK
    Psychol Med 38:1133-40. 2008
    ..We investigated whether school performance at age 16 is associated with risk of adult schizophrenia and other psychoses in a large national cohort, while controlling for multiple confounders...
  29. ncbi request reprint Computation of individual latent variable scores from data with multiple missingness patterns
    D D Campbell
    MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King s College London, De Crespigny Park, Box P080, London, SE5 8AF, UK
    Behav Genet 37:408-22. 2007
    ..The program, documentation and a tutorial, containing worked examples and specimen input and output files, is available at http://statgen.iop.kcl.ac.uk/lsc ...
  30. ncbi request reprint A quantitative genetic analysis of schizotypal personality traits
    Y M Linney
    Department of Psychological Medicine, Institute of Psychiatry, London
    Psychol Med 33:803-16. 2003
    ..Previous twin studies investigating the heritability of schizotypy have often had limited power and have failed to measure the disorganization/social anxiety component...
  31. ncbi request reprint Prenatal exposure to influenza epidemics and risk of mental retardation
    N Takei
    Department of Psychological Medicine, Institute of Psychiatry, London, UK
    Eur Arch Psychiatry Clin Neurosci 245:255-9. 1995
    ..Maternal exposure to influenza at approximately the third to fourth month of gestation may be risk factor for developing mental handicap...
  32. ncbi request reprint Recessive amyotrophic lateral sclerosis families with the D90A SOD1 mutation share a common founder: evidence for a linked protective factor
    A Al-Chalabi
    Departments of Neuroscience and Clinical Neurosciences, Institute of Psychiatry and King s College School of Medicine and Dentistry, De Crespigny Park, Denmark Hill, London SE5 8AF, UK
    Hum Mol Genet 7:2045-50. 1998
    ..We propose a tightly linked protective factor which modifies the toxic effect of mutant SOD1 in recessive families...
  33. ncbi request reprint Identifying potential risk haplotypes for schizophrenia at the DTNBP1 locus in Han Chinese and Scottish populations
    T Li
    Department of Psychiatry, Psychiatry Laboratory, West China Hospital, Sichuan University, PR China
    Mol Psychiatry 10:1037-44. 2005
    ..However, our lack of replication in the Scottish samples also indicates that caution is warranted when evaluating the robustness of the evidence for DTNBP1 as genetic risk factor for schizophrenia...
  34. ncbi request reprint Association analysis of the RGS4 gene in Han Chinese and Scottish populations with schizophrenia
    F Zhang
    Department of Mental Health, University of Aberdeen, Scotland, UK
    Genes Brain Behav 4:444-8. 2005
    ..Differences in the association seen across the two populations could result from methodological factors such as diagnostic differences but most likely result from ethnic differences in haplotype structures within RGS4...
  35. ncbi request reprint A note on the power to detect transmission distortion in parent-child trios via the transmission disequilibrium test
    D M Evans
    Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, OX3 7BN, UK
    Behav Genet 36:947-50. 2006
    ..The corollary is that genome-wide searches are unlikely to identify loci where the level of distortion is small, although they may serve to identify interesting regions worthy of follow up...
  36. ncbi request reprint Investigation of the ability of haplotype association and logistic regression to identify associated susceptibility loci
    B V North
    Institute of Cancer Research, 15 Cotswold Road, Belmont, Sutton, Surrey SM2 5NG, UK
    Ann Hum Genet 70:893-906. 2006
    ..Haplotype analysis may be more prone to such problems than logistic regression, suggesting that the latter method might be preferred...
  37. ncbi request reprint Increased gene coverage and Alu frequency in large linkage disequilibrium blocks of the human genome
    Y Wang
    Genome Research Centre, University of Hong Kong, Pokfulam, Hong Kong SAR, China
    Genet Mol Res 6:1131-41. 2007
    ..We also observed a reduced frequency of Alu repeats at the gaps between large LD blocks, indicating that their enrichment in large LD blocks does not introduce recombination hotspots that would cause these gaps...
  38. ncbi request reprint Association analysis in a variance components framework
    G R Abecasis
    Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
    Genet Epidemiol 21:S341-6. 2001
    ..We examine some of these models and their properties in a blind analysis of the simulated Genetic Analysis Workshop 12 data sets...
  39. ncbi request reprint Further investigation of linkage disequilibrium SNPs and their ability to identify associated susceptibility loci
    B V North
    Academic Department of Psychiatry, Queen Mary s School of Medicine and Dentistry, London E1 1BB, UK
    Ann Hum Genet 68:240-8. 2004
    ..We conclude that one may need to use very dense SNP maps in order to avoid overlooking polymorphisms affecting susceptibility to a common phenotype...
  40. ncbi request reprint The effect of genotype and pedigree error on linkage analysis: analysis of three asthma genome scans
    S S Cherny
    Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
    Genet Epidemiol 21:S117-22. 2001
    ..The results provide empirical evidence for the predicted effects of genotype and relationship error and highlight the need for rigorous detection and elimination of data error in complex trait studies...
  41. ncbi request reprint Do schizophrenic patients who managed to get to university have a non-developmental form of illness?
    J H MacCabe
    Division of Psychological Medicine, Institute of Psychiatry, London
    Psychol Med 32:535-44. 2002
    ..We hypothesized that the aetiology and form of schizophrenia may differ in such patients. We therefore studied a group of schizophrenic patients who were functioning well enough to enter university prior to illness onset...
  42. ncbi request reprint Twin study of symptom dimensions in psychoses
    A G Cardno
    Departments of Psychological Medicine and Medical Genetics, University of Wales College of Medicine, Cardiff, UK
    Br J Psychiatry 179:39-45. 2001
    ..CONCLUSIONS: The disorganised dimension, and possibly other symptom dimensions, may be useful phenotypes for molecular genetic studies of psychoses...
  43. pmc A note on calculation of empirical P values from Monte Carlo procedure
    B V North
    Am J Hum Genet 72:498-9. 2003
  44. ncbi request reprint Affected sibling pair linkage analysis of qualitative and quantitative traits for schizophrenia on chromosome 22 in a Chinese population
    G Cai
    Department of Psychiatry, West China University of Medical Sciences, Sichuan, Chengdu, China
    Am J Med Genet 105:321-7. 2001
    ..LOD score of about 1 are easily produced by chance. Thus, we conclude that under quantitative trait we also find no evidence of linkage between schizophrenia and markers on chromosome 22 in our Chinese sibling pair sample...
  45. ncbi request reprint Assessing optimal neural network architecture for identifying disease-associated multi-marker genotypes using a permutation test, and application to calpain 10 polymorphisms associated with diabetes
    B V North
    Academic Department of Psychiatry, Barts and The London Queen Mary s School of Medicine and Dentistry, London E1 1BB, UK
    Ann Hum Genet 67:348-56. 2003
    ..Permuting only the marker genotypes relative to affection status and these risk factors would allow the contribution of the markers to disease risk to be independently assessed...
  46. doi request reprint Association of a polymorphism in the lipin 1 gene with systolic blood pressure in men
    K L Ong
    Department of Medicine, Faculty of Medicine, University of Hong Kong, Hong Kong
    Am J Hypertens 21:539-45. 2008
    ..The gene is located at 2p25.1, a susceptibility locus for hypertension. We studied the association of tagging single-nucleotide polymorphisms (SNPs) in the lipin 1 (LPIN1) gene with hypertension and blood pressure...
  47. ncbi request reprint Polymorphisms of the gene encoding adiponectin and glycaemic outcome of Chinese subjects with impaired glucose tolerance: a 5-year follow-up study
    A W K Tso
    Department of Medicine, University of Hong Kong, Queen Mary Hospital, 102 Pokfulam Road, Pokfulam, Hong Kong
    Diabetologia 49:1806-15. 2006
    ..The aim of this study was to determine the contribution made by ADIPOQ gene variants to glycaemic status in southern Chinese individuals...
  48. ncbi request reprint Program report: GENECOUNTING support programs
    D Curtis
    Department of Adult Psychiatry, Royal London Hospital, Whitechapel, London E1 1BB, UK
    Ann Hum Genet 70:277-9. 2006
    ....
  49. ncbi request reprint A quick and simple method for detecting subjects with abnormal genetic background in case-control samples
    D Curtis
    Joint Academic Department of Psychological Medicine, St Bartholomew s and Royal London School of Medicine, and Dentistry, UK
    Ann Hum Genet 66:235-44. 2002
    ..We recommend that such tests be routinely applied to case-control samples once sufficient numbers of markers have been genotyped within them...
  50. ncbi request reprint Pre-morbid characteristics and co-morbidity of methamphetamine users with and without psychosis
    C K Chen
    Department of Psychiatry, Chang Gung Memorial Hospital, Taiwan
    Psychol Med 33:1407-14. 2003
    ..We set out to characterize MAMP users and to examine the relationship of pre-morbid personality, pre-morbid social function and other psychiatric disorders to MAMP psychosis...
  51. ncbi request reprint Association of F11 receptor gene polymorphisms with central obesity and blood pressure
    K L Ong
    Department of Medicine, University of Hong Kong, Pokfulam, Hong Kong
    J Intern Med 263:322-32. 2008
    ..We investigated the association of single nucleotide polymorphisms (SNPs) in the F11 receptor gene (F11R) with hypertension and central obesity in Hong Kong Chinese...
  52. ncbi request reprint Number of older siblings of individuals diagnosed with schizophrenia
    C McDonald
    Cluain Mhuire Family Centre, Newtownpark Avenue, Blackrock, County Dublin, Ireland
    Schizophr Res 47:275-80. 2001
    ....