EVIDENCE SUGGESTIVE OF A LOCUS ON CHROMOSOME 5Q31 CONTRIBUTING TO SUSCEPTIBILITY FOR SCHIZOPHRENIA IN GERMAN AND ISRAELI FAMILIES BY MULTIPOINT AFFECTED SIB-PAIR LINKAGE ANALYSIS

Suggestive evidence for a potential susceptibility locus for schizophr enia at 5q31 was obtained in two family samples. Sample I consisted of 14 families with schizophrenia and revealed for the marker IL9 a lod score of 1.8 by two point lod score analysis. Sample II comprised 44 f amilies including four from sample I and was ascertained in order to e mploy affected sib-pair analysis by identity by descent. A lod score o f 1.8 around the marker D5S399 was obtained by multipoint analysis. Th e lod score remained positive, but decreased to 1.27 when the four fam ilies from sample I were excluded in order to use sample II as a stati stically independent replication sample. We propose a susceptibility l ocus for schizophrenia with probably minor contribution in the pedigre es under investigation.