Further tests for linkage of bipolar affective disorder to the tyrosine hydroxylase gene locus on chromosome 11p15 in a new series of multiplex British affective disorder pedigrees.

OBJECTIVE

This study was undertaken to confirm or refute previous reports that link bipolar affective disorder to polymorphic DNA markers at or near the gene for tyrosine hydroxylase.

METHOD

A previous linkage analysis, which used a tetranucleotide repeat polymorphism at the tyrosine hydroxylase locus, of six Icelandic families was extended to include a new series of 17 multiply affected British families.

RESULTS

Overall lod scores under the assumption of locus heterogeneity were between 1.20 and 1.40 at zero recombination with tyrosine hydroxylase, and these scores persisted across three affective disorder models.

CONCLUSIONS

These results provide some support for linking affective disorder to this genetic region and suggest that additional linkage and association studies should be conducted to determine whether tyrosine hydroxylase or a nearby locus contributes to susceptibility to bipolar affective disorder in some families.