Objective: To investigate the association of the Neuregulin 1(NRG1) gene polymorphism with schizophrenia by analyzing allele transmission in schizophrenic parent-proband trios.
Methods: Quantitative real-time PCR was used to check the genotypes of four SNPs-rs221533(C/T), rs7820838(C/T), 433E1006(A/G) and rs3924999(C/T), located at the 5o terminus of the Nrg1 gene, in 258 Chinese Han schizophrenic parent-proband trios. The transmission disequilibrium test (TDT) program (Genehunter software 2.0) was used to evaluate the association of the NRG1 gene with schizophrenia.
Results: For all the subjects, the genotypes of the 4 SNPs were in Hardy-Weinberg equilibrium. In all the 258 parent-proband trios, there were significant transmission disequilibrium in allelic transmission of C, A, T from rs221533, 433E1006, rs3924999 loci respectively (rs221533: chi-square was 27.45, P was 0.000; 433E1006: chi-square was 56.08, P was 0.000; rs3924999: chi-square was 10.53, P was 0.001). Haplotype was analyzed at frequency exceeding 1%. In three-marker-haplotype, C/C/G and C/C/A (marker order: rs221533, rs7820838, 433E1006) transmitted predominantly(C/C/G: chi-square was 5.26, P was 45.08; C/C/A: chi-square was 0.026, P was 0.000). In four-marker-haplotype (marker order: rs221533, rs7820838, 433E1006, rs3924999), C/C/G/T, C/C/A/C and C/C/A/T showed transmission disequilibrium (C/C/G/T: chi-square was 10.71, P was 0.001; C/C/A/C: chi-square was 8.83, P was 0.006, C/C/A/T: chi-square was 27.00, P was 0.000). In the positive subtype of parent-proband trios, C/T/G/C hapoltype transmission was not observed.
Conclusion: The NRG1 gene polymorphism is significantly associated with schizophrenia in Chinese Han, especially in the positive subtype of schizophrenia.