Genomic scan for genes predisposing to schizophrenia

Abstract

We initiated a genome‐wide search for genes predisposing to schizophrenia by ascertaining 9 families, each containing three to five cases of schizophrenia. The 9 pedigrees were initially genotyped with 329 polymorphic DNA loci distributed throughout the genome. Assuming either autosomal dominant or recessive inheritance, 254 DNA loci yielded lod scores less than −2.0 at θ = 0.0, 101 DNA markers gave lod scores less than −2.0 at θ = 0.05, while 5 DNA loci produced maximum lod scores greater than 1: D4S35, D14S17, D15S1, D22S84, and D22S55. Of the DNA markers yielding lod scores greater than 1, D4S35 and D22S55 also were suggestive of linkage when the Affected‐Pedigree‐Member method was used. The families were then genotyped with four highly polymorphic simple sequence repeat markers; possible linkage diminished with DNA markers mapping nearby D4S35, while suggestive evidence of linkage remained with loci in the region of D22S55. Although follow‐up investigation of these chromosomal regions may be warranted, our linkage results should be viewed as preliminary observations, as 35 unaffected persons are not past the age of risk.