Is a mutation in the neuregulin gene associated with schizophrenia in Costa Rica

Marquis P. Vawter; Brandi Rollins; Andrea Mesen ,Beatrice LaPrade Michele Llach; M,William Byerley William E. Bunney; Lynn E DeLisi
World Congress on Psychiatric Genetics XV. 2007.


BACKGROUND: Geographically isolated populations can be particularly useful for finding genes that cause genetically determined disorders. The Central Valley of Costa Rica has been known for its genetic isolation from its early Spanish origin immigrations in the 1600-1800s until recently. We have been acquiring DNA from Spanish-origin families within this region to search for genes for schizophrenia (e.g. DeLisi et al. 2001). Recently, Walss-Bass et al.(2006) reported the presence of a novel missense mutation in the neuregulin 1 gene that is associated with schizophrenia in similar families from Costa Rica. METHODS: Unrelated individuals with a diagnosis of chronic schizophrenia and whose 4 grandparents were of Spanish descent were clinically evaluated and had blood samples drawn for DNA studies. Controls were similarly of Spanish origin and drawn from the surrounding Central Valley community using workers from local companies. Alleles for SNPs for the same markers in the Walss-Bass et al. study were examined in all individuals in the laboratory using standard molecular genetic methods. RESULTS: The missense mutation was found in the same frequency in the control population as in those individuals with schizophrenia. A total of 37 people were genotyped (unaffected n=18, schizophrenia n=8, schizoaffective n=4, major depression n=5, psychosis NOS n=2). Three controls and 2 participants with schizoaffective disorder where heterozygous for the novel mutation (g ), while 3 controls and 1 participant with major depression were homozygous for the mutation (t/t). The remaining participants were all homozygous for the normal genotype (g/g). CONCLUSION: We are attempting to replicate the novel finding of Walss-Bass et al in a similar Spanish origin population, but thus far our results do not suggest an association with schizophrenia. These preliminary results will be supplemented with genotyping of additional individuals to determine the relevance of this missense SNP to the ge netics of schizophrenia in Costa Rica. ACKNOWLEDGEMENT: This project is supported by the Pritzker Foundation