Common sequence variants in the major histocompatibility complex region associate with cerebral ventricular size in schizophrenia.

Background: Because of evidence from genetic linkage and genome-wide association studies, as well as suggested involvement of infection, the major histocompatibility complex (MHC) region on chromosome 6p21.3-22.1 has been implicated in the development of schizophrenia.

Methods: Here, we investigated how gene variants across the MHC region are associated with brain structure in a large ethnically homogenous sample (n = 420), including patients with schizophrenia spectrum disorders and other severe mental illness and healthy control subjects.

Results: We demonstrate highly significant associations between common gene markers in the MHC region and cerebral ventricular volume specifically in schizophrenia spectrum patients (uncorrected p values between 1.16 × 10⁻⁴ and 2.00 × 10⁻⁷). One single nucleotide polymorphism, rs2596532, survives Bonferroni correction for multiple testing across all single nucleotide polymorphisms and brain structure measures (adjusted p value 5.59 × 10⁻⁴).

Conclusions: The results indicate that MHC variants are implicated in characteristic brain abnormalities of schizophrenia.