Association between schizophrenia and UFD1L, a developmental gene mapped to chromosome 22

Schizophrenia or schizoaffective disorders are often found in patients affected by DiGeorge/velo-cardio-facial syndrome (DGS/VCFS) as a result of hemizygosity of chromosome 22q11.2. We evaluated the UFD1L gene, mapping within the DGS/VCFS region, as a potential candidate for schizophrenia susceptibility. UFD1L encodes for the Ubiquitin Fusion Degradation 1 Protein, which is expressed in the medial telencephalon during mouse development. UFD1L mRNA and protein were investigated by RT-PCR and Western blot analysis. The UFD1L promoter -277A/G polymorphism was determined using a polymerase chain reaction-based method in DNA samples from 61 patients with DSM-IV schizophrenia and 67 healthy control subjects. Results were confirmed in 22 nuclear families using a TDT analysis. We demonstrated the presence of UFD1L mRNA and protein in different areas of the human brain, and found a positive association between a novel intragenic SNP (Single Nucleotide Polymorphism) and schizophrenia. We demonstrated that the -277A variant of this SNP is associated with schizophrenia susceptibility. In addition, we also provided evidence that this allele variant causes a 55% increase in the transcriptional activity of UFD1L gene. This results suggests the involvement of the UFD1L gene in susceptibility to schizophrenia.