Effects of NRG1 genotypes on orbitofrontal sulcogyral patterns in Japanese patients diagnosed with schizophrenia

Numerous reports have described differences in the distribution of orbitofrontal cortex (OFC) sulcogyral patterns between patients with schizophrenia (SZ patients) and healthy controls (HC). Alterations in OFC morphology are also observed in those at high risk for developing SZ and in first-episode SZ, suggesting that genetic associations may be extant in determining OFC sulcogyral patterns. We investigated the association between single nucleotide polymorphisms (SNP) in NRG1 and OFC sulcogyral patterns.

A total of 59 Japanese patients diagnosed with SZ and 60 HC were scanned on a 1.5-T magnet. Patients were also assessed clinically. OFC sulcogyral patterns were evaluated for each participant, and genotyping was performed for four SNP in NRG1 (SNP8NRG243177, SNP8NRG221533, SNP8NRG241930, and rs1081062).

There were significant differences in the distribution of OFC sulcogyral patterns between SZ patients and HC (χ(2) = 6.52, P = 0.038). SZ patients showed an increase in the frequency of Type III expression, which was associated with an earlier age of disease onset (β = -0.302, F = 4.948, P = 0.030). Although no difference was found in genotype frequencies between SZ patients and HC, an NRG1 SNP, SNP8NRG243177, was associated with Type II expression in SZ patients (β = 0.237, F = 4.120, P = 0.047).

Our results suggest that OFC sulcogyral pattern formation in schizophrenia may be associated with NRG1 allele frequency, which is closely related to neurodevelopment.