Genetic Epidemiology, Translational Neurogenomics, Psychiatric Genetics and Statistical Genetics Laboratories investigate the pattern of disease in families, particularly identical and non-identical twins, to assess the relative importance of genes and environment in a variety of important health problems.
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PMID
16611462
TITLE
False disease region identification from identity-by-descent haplotype sharing in the presence of phenocopies.
ABSTRACT
Linkage analysis (either parametric or nonparametric) is commonly applied to identify chromosomal regions using related individuals affected by disease. In complex disease the incomplete relationship between phenotype and genotype can be modeled using a phenocopy parameter, the probability that an individual is affected given they do not carry the disease mutation of interest, and a nonpenetrance parameter, the probability that an individual is not affected given they do carry the disease mutation of interest. If the linkage phase between multiple markers and a putative disease locus is known, then haplotypes carrying the mutation can, in principle, be identified by comparing the chromosome segments that are shared identical-by-descent (IBD) across affected individuals. We consider here the effect of a nonzero phenocopy rate on the linkage peak and hence upon the identification of disease haplotypes that are shared IBD between affected individuals. We show, by theory and computer simulation, that in diseases for which there is a nonzero phenocopy rate, the chromosomal regions identified may not include the true disease locus. We utilize a LOD-1 confidence interval for a widely used nonparametric linkage statistic. We find that in small/moderate samples this confidence interval may be inappropriate. We give specific examples where the phenocopy rates are nonnegligible in some complex diseases. The success of further work to identify the causal mutations underlying the linkage peaks in these diseases will depend on researchers allowing for the presence of phenocopies by examining appropriately wide regions around the initial positive linkage finding.
DATE PUBLISHED
2006 Feb
HISTORY
PUBSTATUS PUBSTATUSDATE
pubmed 2006/04/14 09:00
medline 2006/05/12 09:00
entrez 2006/04/14 09:00
AUTHORS
NAME COLLECTIVENAME LASTNAME FORENAME INITIALS AFFILIATION AFFILIATIONINFO
Macgregor S Macgregor Stuart S Institute of Evolutionary Biology, University of Edinburgh, West Mains Road, Edinburgh, United Kingdom. stuart.macgregor@qimr.edu.au
Knott SA Knott Sara A SA
Visscher PM Visscher Peter M PM
INVESTIGATORS
JOURNAL
VOLUME: 9
ISSUE: 1
TITLE: Twin research and human genetics : the official journal of the International Society for Twin Studies
ISOABBREVIATION: Twin Res Hum Genet
YEAR: 2006
MONTH: Feb
DAY:
MEDLINEDATE:
SEASON:
CITEDMEDIUM: Print
ISSN: 1832-4274
ISSNTYPE: Print
MEDLINE JOURNAL
MEDLINETA: Twin Res Hum Genet
COUNTRY: England
ISSNLINKING: 1832-4274
NLMUNIQUEID: 101244624
PUBLICATION TYPE
PUBLICATIONTYPE TEXT
Journal Article
Research Support, Non-U.S. Gov't
COMMENTS AND CORRECTIONS
GRANTS
GENERAL NOTE
KEYWORDS
MESH HEADINGS
DESCRIPTORNAME QUALIFIERNAME
Alleles
Computer Simulation
Genetic Linkage
Genetic Markers
Genotype
Haplotypes genetics
Humans genetics
Inheritance Patterns genetics
Lod Score genetics
Models, Genetic genetics
Mutation genetics
Phenotype genetics
Statistics, Nonparametric genetics
SUPPLEMENTARY MESH
GENE SYMBOLS
CHEMICALS
REGISTRYNUMBER NAMEOFSUBSTANCE
0 Genetic Markers
OTHER ID's