Copyright © 2005 The American Society of Human Genetics. All rights reserved.
The American Journal of Human Genetics, Volume 77, Issue 3, 500-512, 1 September 2005
doi:10.1086/444510
Report
Dale R. Nyholt1,
,
, Katherine I. Morley1, 2, Manuel A.R. Ferreira1, Sarah E. Medland1, 3, Dorret I. Boomsma4, Andrew C. Heath5, Kathleen R. Merikangas6, Grant W. Montgomery1 and Nicholas G. Martin1
1 Queensland Institute of Medical Research, Brisbane, Australia
2 Institute for Molecular Bioscience, The University of Queensland, Queensland, Australia
3 Department of Psychology, The University of Queensland, Queensland, Australia
4 Department of Biological Psychology, Free University, Amsterdam
5 Department of Psychiatry, Washington University School of Medicine, St. Louis, MO
6 Section on Developmental Genetic Epidemiology, Intramural Research Program, National Institute of Mental Health, National Institutes of Health, Bethesda, MD
Address for correspondence and reprints: Dr. Dale R. Nyholt, Queensland Institute of Medical Research, Post Office Royal Brisbane Hospital, Brisbane QLD 4029, AustraliaAbstract
Familial typical migraine is a common, complex disorder that shows strong familial aggregation. Using latent-class analysis (LCA), we identified subgroups of people with migraine/severe headache in a community sample of 12,245 Australian twins (60% female), drawn from two cohorts of individuals aged 23–90 years who completed an interview based on International Headache Society criteria. We report results from genomewide linkage analyses involving 756 twin families containing a total of 790 independent sib pairs (130 affected concordant, 324 discordant, and 336 unaffected concordant for LCA-derived migraine). Quantitative-trait linkage analysis produced evidence of significant linkage on chromosome 5q21 and suggestive linkage on chromosomes 8, 10, and 13. In addition, we replicated previously reported typical-migraine susceptibility loci on chromosomes 6p12.2-p21.1 and 1q21-q23, the latter being within 3 cM of the rare autosomal dominant familial hemiplegic migraine gene (ATP1A2), a finding which potentially implicates ATP1A2 in familial typical migraine for the first time. Linkage analyses of individual migraine symptoms for our six most interesting chromosomes provide tantalizing hints of the phenotypic and genetic complexity of migraine. Specifically, the chromosome 1 locus is most associated with phonophobia; the chromosome 5 peak is predominantly associated with pulsating headache; the chromosome 6 locus is associated with activity-prohibiting headache and photophobia; the chromosome 8 locus is associated with nausea/vomiting and moderate/severe headache; the chromosome 10 peak is most associated with phonophobia and photophobia; and the chromosome 13 peak is completely due to association with photophobia. These results will prove to be invaluable in the design and analysis of future linkage and linkage disequilibrium studies of migraine.
| Evidence of Linkage of Familial Hypoalphalipoproteinemia to a Novel Locus on Chromosome 11q23 The American Journal of Human Genetics, Volume 66, Issue 6, 1 June 2000, Pages 1845-1856 E.N. Kort, D.G. Ballinger, W. Ding, S.C. Hunt, B.R. Bowen, V. Abkevich, K. Bulka, B. Campbell, C. Capener, A. Gutin, K. Harshman, M. McDermott, T. Thorne, H. Wang, B. Wardell, J. Wong, P.N. Hopkins, M. Skolnick and M. Samuels Abstract Coronary heart disease (CHD) accounts for half of the 1 million deaths annually ascribed to cardiovascular disease and for almost all of the 1.5 million acute myocardial infarctions. Within families affected by early and apparently heritable CHD, dyslipidemias have a much higher prevalence than in the general population; 20%-30% of early familial CHD has been ascribed to primary hypoalphalipoproteinemia (low HDL-C). This study assesses the evidence for linkage of low HDL-C to chromosomal region 11q23 in 105 large Utah pedigrees ascertained with closely related clusters of early CHD and expanded on the basis of dyslipidemia. Linkage analysis was performed by use of 22 STRP markers in a 55-cM region of chromosome 11. Two-point analysis based on a general, dominant-phenotype model yielded LODs of 2.9 for full pedigrees and 3.5 for 167 four-generation split pedigrees. To define a localization region, model optimization was performed using the heterogeneity, multipoint LOD score (mpHLOD). This linkage defines a region on 11q23.3 that is ∼10 cM distal to—and apparently distinct from—the ApoAI/CIII/AIV gene cluster and thus represents a putative novel localization for the low HDL-C phenotype. Abstract | | |
| The Inheritance of Neuropsychological Dysfunction in Twins Discordant for Schizophrenia The American Journal of Human Genetics, Volume 67, Issue 2, 1 August 2000, Pages 369-382 Tyrone D. Cannon, Matti O. Huttunen, Jouko Lonnqvist, Annamari Tuulio-Henriksson, Tiia Pirkola, David Glahn, Jennifer Finkelstein, Marja Hietanen, Jaakko Kaprio and Markku Koskenvuo Abstract While genetic influences in schizophrenia are substantial, the disorder's molecular genetic basis remains elusive. Progress has been hindered by lack of means to detect nonpenetrant carriers of the predisposing genes and by uncertainties concerning the extent of locus heterogeneity. One approach to solving this complexity is to examine the inheritance of pathophysiological processes mediating between genotype and disease phenotype. Here we evaluate whether deficits in neurocognitive functioning covary with degree of genetic relationship with a proband in the unaffected MZ and DZ co-twins of patients with schizophrenia. Twin pairs discordant for schizophrenia were recruited from a total population cohort and were compared with a demographically balanced sample of control twin pairs, on a comprehensive neuropsychological test battery. The following four neuropsychological functions contributed uniquely to the discrimination of degree of genetic loading for schizophrenia and, when combined, were more highly correlated within MZ pairs than within DZ pairs, in both discordant and control twins: spatial working memory (i.e., remembering a sequence of spatial locations over a brief delay), divided attention (i.e., simultaneous performance of a counting and visual-search task), intrusions during recall of a word list (i.e., “remembering” nonlist items), and choice reaction time to visual targets. Together with evidence from human and animal studies of mediation of these functions by partially distinct brain systems, our findings suggest that there are multiple independently inherited dimensions of neural deficit in schizophrenia and encourage a search for genes contributing to quantitative variation in discrete aspects of disease liability. On tests of verbal and visual episodic memory, but not on the liability-related measures, patients were more impaired than their own MZ co-twins, suggesting a preferential impact of nongenetic influences on long-term memory systems. Abstract | | |