Genetic linkage of schizophrenia to markers at 5q11.2–13.3 had been reported previously in five
Icelandic and two British families, but attempts at replication in independent samples have been
unsuccessful. We report here an update on the diagnoses and results of linkage analyses using newer
highly polymorphic microsatellite markers at or near the loci D5S76 and D5S39 in the original
sample of pedigrees and in two new family samples from Iceland and from Britain. The new results
show a reduction in evidence for linkage in the original sample and evidence against linkage in the
two new family samples. Although it is possible that a rare locus is present, perhaps in the region
5p14.1–13.1 rather than 5q11.2–13.3, it appears most likely that the original positive lod scores
represent an exaggeration of the ‘true’ lod scores due to random effects and that the small lod scores
we now obtain could have arisen by chance.