Department of Veterans Affairs Cooperative Studies Program genetic linkagestudy of schizophrenia: Ascertainment methods and sample description

To help clarify the genetics of schizophrenia, the Department of Veterans A ffairs Cooperative Studies Program has completed data collection for a gene tic linkage study of schizophrenia, This article describes the methodologic al details of the data collection. Subsequent articles will describe the re sults of our genome scan, which is now in progress. The data collection pro tocol included the Diagnostic Interview for Genetic Studies, the Family Int erview for Genetic Studies, a review of medical records, and the collection of blood for transformation into lymphoblast cell lines. Among relatives o f schizophrenic probands, we assessed auditory attention and verbal memory with neuropsychological tests. Among the 166 families ascertained for the s tudy, 143 had a single affected sib-pair, 17 had three affected siblings, o ne had five affected siblings and five had two sets of affected siblings. T here was a total of 216 affected sib-pairs in these families, Using the n-1 rule, these families contain 188 independent affected sib-pairs. Am. J. Me d. Genet. (Neuropsychiatr. Genet,) 96:342-347, 2000. (C) 2000 Wiley-Liss, I nc.