Mutation screening of a neutral amino acid transporter, ASCT1, and its potential role in schizophrenia

In a previous study, a genome scan of a subset of schizophrenia families from Palau, Micronesia gave evidence suggestive of linkage to microsatellite markers at 2p13-14. In addition, in a large extended multiplex pedigree (K1583), an 11 cM 2p13-14 haplotype segregated with the illness in eight distantly related schizophrenics. The haplotype region includes a neutral amino acid transporter, ASCT1. We mutation-screened the coding region, flanking intronic sequence and 5'-untranslated region of this transporter in affected members of K1583, two Palauan controls and one Caucasian control. Most polymorphisms were found to be silent or common to all samples scanned. A G/A heterozygote within intron 3 was found in one schizophrenic member of K1583, but was not found in any of the other affected members of K1583. A G/A heterozygote within intron 6 was found in two of six schizophrenics tested in K1583, and in one control. As none of the sequence polymorphisms segregated with illness in the eight schizophrenics, it is unlikely that changes in the 5'-untranslated region, coding sequence or flanking intronic sequence of the ASCT gene predispose to schizophrenia in these families.