Evidence for a schizophrenia vulnerability locus on chromosome 8p in the Irish Study of High-Density Schizophrenia Families

Am J Psychiatry. 1996 Dec;153(12):1534-40. doi: 10.1176/ajp.153.12.1534.


Objective: This study was an attempt to replicate evidence for a vulnerability locus for schizophrenia and associated disorders in the 8p22-21 region reported by Pulver and colleagues.

Method: The linkage sample of the Irish Study of High-Density Schizophrenia Families consists of 265 multiplex families containing 1,408 individuals. Fifteen markers covering 30 centimorgans on chromosome 8p were tested. Three statistical methods were used: two-point and multipoint heterogeneity lod scores and a multipoint nonparametric test.

Results: According to two-point heterogeneity lod scores, the strongest evidence for linkage was found for markers D8S1731 (maximum lod score = 2.00), D8S1715 (maximum lod score = 2.52), and D8S133 (maximum lod score = 2.08) by assuming a phenotypic definition of all psychiatric illness and a range of genetic models. According to multipoint heterogeneity lod scores, the strongest evidence for linkage (maximum lod score = 2.34), found by using a dominant genetic model and a broad definition of the schizophrenia spectrum, extended over a 10-cM region between markers D8S1715 and D8S1739. Multipoint nonparametric linkage found the strongest evidence (maximum z = 2.51) over a broader region when either a diagnosis of core schizophrenia or a narrow definition of the schizophrenia spectrum was used. This putative vulnerability locus was segregating in 10%-25% of the families studied.

Conclusions: This study supports the existence of a vulnerability locus for schizophrenia on chromosome 8p. In this sample, this locus appears to influence the risk of illness in only a modest proportion of families and predisposes to a range of schizophrenia spectrum and possibly nonspectrum disorders.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Chromosomes, Human, Pair 8 / genetics*
  • Family*
  • Female
  • Genetic Heterogeneity
  • Genetic Linkage*
  • Genetic Markers
  • Humans
  • Ireland / epidemiology
  • Lod Score
  • Male
  • Models, Genetic
  • Pedigree
  • Schizophrenia / epidemiology
  • Schizophrenia / genetics*


  • Genetic Markers