Second stage of a genome scan of schizophrenia: Study of five positive regions in an expanded sample

In a previous genome scan of 43 schizophrenia pedigrees, nonparametric Link age (NPL) scores with empirically derived pointwise P-values less than 0.01 were observed in two regions (chromosomes 2q12-13 and 10q23) and less than 0.05 in three regions (4q22-23, 9q22, and 11q21). Markers with a mean spac ing of about 5 cM were typed in these regions in an expanded sample of 71 p edigrees, and NPL analyses carried out. No region produced significant geno mewide evidence for linkage. On chromosome 10q, the empirical P-value remai ned at less than 0.01 for the entire sample (D10S168), evidence in the orig inal 43 pedigrees was slightly increased, and a broad peak of positive resu lts was observed. P-values less than 0.05 were observed on chromosomes 20 ( D2S436) and 4q (D4S2623), but not on chromosomes 9q or 11q. It is concluded that this sample is most supportive of linkage on chromosome 10q, with les s consistent support on chromosomes 2q and 4q. (C) 2000 Wiley-Liss, Inc.