P. V. Gejman

Report of the Chromosome 5 Workshop of the Sixth World Congress on Psychiatric Genetics

The Chromosome 5 Workshop heard new data on a schizophrenia susceptibility locus in the 5q23.3-q31.1 region. Sixty-two pedigrees from Finland gave a lod score of 1.36 at the CSF1R locus approximately 14 cM distal to IL9/D5S393, where positive results from three pedigree collections converged at the 1997 workshop. Though positive at CSF1R, the new data were only weakly positive at the IL9 (lod 0.46) and D5S393 (lod 0.07) loci themselves. The workshop also reviewed new evidence in the 5p14.1-p13.1 region, where a large pedigree of schizophrenia of Puerto Rican extraction has suggested a susceptibility locus with a maximum lod score at D5S111. Twenty-one new pedigrees multiplex for schizophrenia in African Americans gave positive lod scores at D5S111 and flanking loci. In bipolar illness five genetically related pedigrees from the Saguenay-Lac-St. Jean region of Quebec identified a region of interest at 5q31.3-q35.1. This region overlaps with the D5S423 locus and includes the D5S812 locus and the 5q34 region, all of which are consistent with linkage in at least one other study.

Sixth World Congress of Psychiatric Genetics X chromosome workshop

At the X chromosome workshop of the Sixth World Congress on Psychiatric Genetics, new data regarding psychiatric phenotypes and the X chromosome were presented. In the last year a number of groups have published linkage results for the X chromosome in schizophrenia, which provide no significant evidence for linkage. Presentations by groups from Cardiff, Oxford, State University of New York (SUNY), and Finland provide weak nonsignificant evidence for linkage of markers on the Xp11.4-p11.3, Xq21, and Xq26 with schizophrenia. However, the presence of a male-specific transmission ratio distorter (DMS1) that maps to Xp11.4-21.2 [Naumova et al., 1998: Am. J. Hum. Genet. 62:1493-1499] makes the interpretation of linkage findings in brother-brother pairs difficult in this region. Regarding bipolar affective disorder, little new data were reported, but previous reports provide evidence for linkage to Xq25-q26. Summary tables of linkage results for schizophrenia and bipolar disorder can be obtained from http://www.camh.net/ research/x-chromosome/. No linkage or transmission disequilibrium of polymorphisms of MAOA and MAOB in attention deficit hyperactivity disorder was seen. Negative results for transmission disequilibrium of polymorphisms of HTR2C and MAOA with autism were provided from German and Austrian families.