RESUMEN
Prior work found the APOL1, 2 and 4 genes, located on chromosome 22q12.3-q13.1, to be upregulated in brains of schizophrenic patients. We performed a family-based association study using 130 SNPs tagging the APOL gene family (APOL1-6). The subjects were 112 African-American (AA), 114 European-American (EA), 109 Chinese (Ch) and 42 Japanese (Jp) families with schizophrenia (377 families, 1161 genotyped members and 647 genotyped affected in total). Seven SNPs had p-values<0.05 in the APOL1, 2 and 4 regions for the AA, EA and combined (AA and EA) samples. In the AA sample, two SNPs, rs9610449 and rs6000200 showed low p-values; and a haplotype which comprised these two SNPs yielded a p-value of 0.00029 using the global test (GT) and the allele specific test (AST). The two SNPs and the haplotype were associated with risk for schizophrenia in African-Americans. In the combined (AA and EA) sample, two SNPs, rs2003813 and rs2157249 showed low p-values; and a three SNP haplotype including these two SNPs was significant using the GT (p=0.0013) and the AST (p=0.000090). The association of this haplotype with schizophrenia was significant for the entire (AA, EA, Ch and Jp) sample using the GT (p=0.00054) and the AST (p=0.00011). Although our study is not definitive, it suggests that the APOL genes should be more extensively studied in schizophrenia.
Asunto(s)
Apolipoproteínas/genética , Haplotipos/genética , Lipoproteínas HDL/genética , Polimorfismo de Nucleótido Simple/genética , Esquizofrenia/genética , Negro o Afroamericano/genética , Apolipoproteína L1 , Apolipoproteínas L , Pueblo Asiatico/genética , Cromosomas Humanos Par 22/genética , Frecuencia de los Genes , Genotipo , Humanos , Esquizofrenia/etnología , Población Blanca/genéticaRESUMEN
BACKGROUND: A family based association study in a British sample found the NOTCH4 gene to be associated with schizophrenia; however, all six replication studies failed to confirm the finding. METHODS: We performed a family based association study of NOTCH4 and schizophrenia in 123 trios (16 Japanese and 107 Chinese). In addition to the original study's polymorphisms, we examined four new single nucleotide polymorphisms (SNPs)--SNPs_A, B, C and D--around SNP1 of the original study. We genotyped all samples for SNPs_A-D and for SNP1 and (CTG)n of the original study. RESULTS: We found no significant associations between NOTCH4 and schizophrenia or its subtypes for all polymorphisms, regardless of gender. The finding remained negative when the Chinese sample was analyzed separately. Exploratory analyses suggested that SNP_A may be associated with early-onset schizophrenia and that SNP1 may be associated with schizophrenia characterized by numerous negative symptoms. CONCLUSIONS: NOTCH4 is not a significant susceptibility gene for schizophrenia when clinical heterogeneity is ignored; however, NOTCH4 may be associated with early-onset schizophrenia or schizophrenia with many negative symptoms, but these findings should be interpreted cautiously.
Asunto(s)
Pueblo Asiatico/genética , Polimorfismo Genético , Proteínas Proto-Oncogénicas/genética , Receptores de Superficie Celular , Esquizofrenia/genética , Adulto , Edad de Inicio , Anciano , China , Familia , Femenino , Genotipo , Haplotipos , Humanos , Japón , Masculino , Persona de Mediana Edad , Receptor Notch4 , Receptores NotchRESUMEN
Several studies suggest that loci at chromosome 22q11.2-q13 might be linked to susceptibility to schizophrenia. Here we performed family-based association studies on chromosome 22q using 12 DNA microsatellite markers in African-American, European-American, and Chinese pedigrees. The marker D22S683 showed significant linkage and association with schizophrenia in not only the European-American sample but also in a combined sample (European-American and Chinese samples). Notably, D22S683 is located nearby and between D22S278 and D22S283, which have shown linkage and association to schizophrenia in prior reports. However, we found no significant association for the African-American sample. In conclusion, our data provide further support for the idea that the region around D22S683 contains a susceptibility gene for schizophrenia.