Association of Genetic Variation in the MET Proto-Oncogene With Schizophrenia and General Cognitive Ability

Objective: Despite increased exposure to cancer risk factors, several studies have demonstrated a lower incidence of cancer in schizophrenia patients than in the general population. Lower cancer rates in first-degree relatives of schizophrenia patients suggest that the inverse relationship between cancer and schizophrenia may be related to genetic factors. Few studies of schizophrenia have focused on cancer-related genes. The MET proto-oncogene is primarily linked to tumor metastasis, but MET is also involved in neurodevelopment and influences risk for autism. Thus, MET may be of particular interest as a candidate gene for neuropsychiatric diseases with a developmental etiology, including schizophrenia. Method: The authors examined the relationship between 21 single-nucleotide polymorphisms in MET and schizophrenia in 173 Caucasian patients and 137 comparison subjects. They then genotyped a second independent sample (107 patients and 112 comparison subjects) for replication. Finally, they tested for MET's effects on general cognitive ability (g). Results: In the initial cohort, the authors identified four haplotype blocks and found one block to be globally associated with schizophrenia. In block 3, the most common haplotype was over-represented in comparison subjects (frequency, 47%) relative to schizophrenia patients (frequency, 33%) (p=4.0x10(-4); odds ratio=0.56). The authors replicated the block 3 finding in the second sample with similar frequencies: 46% in comparison subjects and 36% in schizophrenia patients (p=0.03; odds ratio=0.66). Moreover, the protective haplotype was associated with a higher g in the combined comparison sample. Conclusions: These data suggest that MET variation influences schizophrenia risk and neurocognition, supporting a neurodevelopmental role across CNS-relevant phenotypes. These results add to the growing evidence suggesting an intriguing relationship between cancer-related genes and schizophrenia susceptibility.