Schizophrenia is a prevalent mental disorder characterized by typical symptoms including false beliefs, unclear or confused thinking auditory hallucinations, reduced social engagement and emotional expression, and lack of motivation. The lifetime prevalence of schizophrenia worldwide is up to 1%. According to what people have known about schizophrenia, it has been generally accepted that the pathogenesis of schizophrenia is a combination of both genetic and environmental factors, and the latter accounts for a major role (heritability as high as 81%).

Although existing studies have reported many schizophrenia susceptible genes and single nucleotide polymorphisms (SNPs), the genetic basis and underlying mechanisms of schizophrenia are still unclear. One of the assumptions is that the mitochondrial dysfunction is one of the reasons of the incidence of schizophrenia because human brain is the most energy-intensive human organ and it consumes 20%-25% of body's total energy consumption. The mitochondria is the powerhouse of cells. Therefore, the relationship between mitochondria and schizophrenia has aroused great attentions.

To explore the potential association between mitochondrial complex I, the largest and complicated component of the respiratory chain in electron transportation and schizophrenia, Dr. CHEN Xiaogang from the Second Xiangya Hospital and Dr. YAO Yonggang's group from Kunming Institute of Zoology of Chinese Academy of Sciences collaboratively conducted a genetic association study by genotyping 46 tag SNPs from seven nuclear-encoded genes of mitochondrial complex I in Han Chinese with and without schizophrenia and reanalysis of the Psychiatric Genetics Consortium (PGC) dataset.

The results demonstrated that by using a rigorous statistical standard to avoid possible false positive results, researchers found no significant association between genetic polymorphisms from the seven selected genes of mitochondrial complex I and schizophrenia, suggesting that these genes are unlikely to confer risk of schizophrenia in Han Chinese population. Moreover, no robust association between these SNPs and schizophrenia in the PGC data were observed. The analyses to test if genetic variants of these seven nuclear-encoded genes of mitochondrial complex I were associated with early onset schizophrenia (EOS, patients with a younger age of onset, usually below 18) in Han Chinese also showed up negatively.

These findings suggest that common SNPs in the nuclear-encoded core subunit genes of mitochondrial complex I may not confer genetic susceptibility to schizophrenia. This study for the first time systematically analyzed the genetic correlation between mitochondrial complex I and schizophrenia and was published on Scientific Reports.