Transmission of NOTCH4 and GRIK2 in a population of Han Chinese with schizophrenia and affective disorder

Zuowei Wang; Yiru Fang; Shaoping Zhang; Shunying Yu; Sanduo Jiang

摘要：BACKGROUND: Increasing evidence suggests overlapped genetic susceptibility across traditional classification systems that divided psychotic disorders into schizophrenia or affective disorder.OBJECTIVE: This study aimed to explore whether schizophrenia and affective disorder share genetic susceptibility in NOTCH4 and GRIK2 loci in a population of Han Chinese. DESIGN: Repetitive measurements.SETTING: The experiment was carried out at Shanghai Mental Health Center and Hongkou Mental Health Center of Shanghai between January 2001 and June 2004.PARTICIPANTS: Sixty-five mixed pedigrees (suffering from various diseases, in combination with schizophrenia and affective disorder), composed of 45 completed trios and 20 single-parent families, were selected from Shanghai Mental Health Center and Hongkou Mental Health Center of Shanghai between January 2001 and June 2004. Probands received clinical diagnosis according to ICD-10; an independent clinician used identical criteria to review all diagnoses. All subjects were Han Chinese in origin and provided informed consent. There were 65 probands and 110 parents among the subjects. The probands comprised 30 males and 35 females: 33 with schizophrenia, 32 with affective disorder, mean age of (30.9 ± 9.8) years, mean age of onset (24.3 ± 8.8) years, mean duration (6.6 ± 7.0) years, and mean age of parents (58.8 ± 10.9) years.METHODS: DNA samples from probands and their biological parents were extracted from peripheral blood according to standard methods. Four polymorphisms, -1725T/G and -25T/C in NOTCH4, rs6922753T/C and rs2227283G/A in GRIK2, were amplified and genotyped with PCR-RFLP techniques. MAIN OUTCOME MEASURES: Association between NOTCH4, GRIK2 polymorphism, and schizophrenia was analyzed by transmission disequilibrium test (TDT).RESULTS: Sixty-five probands and 110 parents were included in the result analysis, with no dropouts. The results showed that the -25T/C polymorphism of NOTCH4 associated significantly with affective disorder and -1725G/-25T haplotype with schizophrenia. SNP rs6922753 of GRIK2 did not associate with the two diseases; SNP rs2227283 and haplotypes, TG and CA, were significantly associated with both diseases.CONCLUSION: Schizophrenia and affective disorder might share genetic susceptibility among mixed pedigrees of the Han Chinese population. NOTCH4 and GRIK2 might be two of the most common susceptibility genes for these psychoses.