Typically, each successive linkage study of a single gene illness offers more conclusive results, until the gene's location becomes clear.

As a result, it is anyone's guess how to interpret the combined findings of psychiatric linkage studies.

Such internal replication "sets a new standard for how linkage studies should be done," he said.

Genetic linkage studies analyze the spacial arrangements of genes and chromosomes.

Although the first genetic linkage finding for mania was in 1969, the linkage studies have been inconsistent.

However, for common and complex diseases the results of genetic linkage studies proved hard to reproduce.

A suggested alternative to linkage studies was the genetic association study.

Early calculations on statistical power indicated that this approach could be better than linkage studies at detecting weak genetic effects.

A 2003 review of linkage studies listed seven genes as likely to increase risk for a later diagnosis of the disorder.

Traditional genetic linkage studies which are followed by positional cloning require a large number of affected individuals.