Relationship of SNAP25 variants with schizophrenia and antipsychotic-induced weight change in large-scale...

The SNAP25 gene is involved in the development of antipsychotic-induced weight gain (AIWG) or metabolic syndrome during antipsychotics use in Americans and Europeans, but its role in Asians remains unknown. To identify common variants in SNAP25 associated with schizophrenia and evaluate their effects on AIWG and antipsychotic responses in Han Chinese individuals with schizophrenia, we conducted a two-stage case-control study of 3,243 patients and 6,154 healthy controls. 2128 inpatients in the replication stage have received conventional treatment with an antipsychotic monotherapy (Haloperidol, Olanzapine or Risperidone) for 10 weeks at least. Weight change, antipsychotic responses and metabolic indices change were assessed during treatments. Three SNPs were significantly associated with schizophrenia in samples (rs6039769, P = 6.64 × 10^-7; rs3787283, P = 0.004283; rs3746544, P = 2.51 × 10^-6). Of these, rs6039769 is a novel schizophrenia-associated SNP and is uncorrelated with the other two variants, which have previously been associated with schizophrenia in European-ancestry samples. Rs6039769 was significantly associated with AIWG (P < 0.001), but not with antipsychotic responses or metabolic indices. Another two SNPs were not associated with AIWG or antipsychotic responses or metabolic indices. Overall, there were significant differences in antipsychotic responses and metabolic indices among the three treatment groups. Our findings suggest that SNAP25 gene may contribute to the susceptibility of AIWG and even metabolic disturbances. A prior identification of high-risk of patients with rs6039769 would contribute to a better precision of the pharmacological treatment.