Searching for a schizophrenia susceptibility gene in the 22q11 region

OBJECTIVE: To investigate a genetic association for schizophrenia within chromosome 22q11 in a Chinese Han population. METHODS: The PCR-based restriction fragment length polymorphism (PCR-RFLP) analysis was used to detect three single nucleotide polymorphisms (SNPs), rs165655 (A/G base change) and rs165815 (C/T base change) present in the ARVCF (armadillo repeat gene deletion in velocardiofacial syndrome) locus, and rs756656 (A/C base change) in the LOC128979 (expressed sequence tags, EST) locus, among 100 Chinese family trios consisting of fathers, mothers and affected offspring with schizophrenia. Genotype data were analyzed by using linkage disequilibrium (LD) methods including haplotype relative risk (HRR) analysis, transmission disequilibrium test (TDT) and haplotype transmission analysis. RESULTS: The genotype frequency distributions of three SNPs were all in Hardy-Weinberg equilibrium (P>0.05). Both the HRR and the TDT analysis showed that rs165815 was associated with schizophrenia (chi2=6.447, df=1, P=0.011 and chi2=6.313, df=1, P=0.012, respectively), whereas the other two SNPs did not show any allelic association. The haplotype transmission analysis showed a biased transmission for the rs165655-rs165815 haplotype system (chi2=17.224, df=3, P=0.0006) and for the rs756656-rs165655-rs165815 hapoltype system (chi2=20.965, df=7, P=0.0038). CONCLUSION: Either the ARVCF gene itself or a nearby locus may confer susceptibility to schizophrenia in a Chinese Han population.