Chromosome 5 and schizophrenia: implications for genetic linkage studies.

Two years ago, a family with two members who shared a chromosomal anomaly (partial trisomy of the long arm of chromosome 5), mild physical abnormalities, and schizophrenia was reported. This special family provided a candidate region on chromosome 5 for linkage studies of schizophrenia. The background of the finding is examined, and the specific features of the original report are outlined. A description of the immediate implications of the chromosome 5 abnormality for linkage studies leads to a discussion of the broader clinical, methodological, and ethical issues involved. Solutions to the many questions arising from this new wave of genetic linkage studies will require active involvement of researchers, clinicians, and families.