Objective: The MCHR1 gene encoding the melanin-concentrating hormone receptor 1 is located on chromosome 22q13.2 and has previously been associated with schizophrenia in a study of cases and controls from the Faroe Islands and Scotland. Herein we report an association between variations in the MCHR1 gene and schizophrenia, based on analyses of a larger sample and an increased number of single nucleotide polymorphisms (SNPs) than used in the previous study.
Methods: Eighteen SNPs in the MCHR1 gene region were genotyped in a Caucasian case-control sample from Denmark consisting of 390 individuals with schizophrenia and 814 control individuals. Sex-specific analysis and analysis of association with antipsychotic treatment were performed.
Results: Five SNPs in the proximal region of MCHR1 were significantly associated with schizophrenia. The associations seemed to be sex specific, predominantly seen in men where one SNP (rs133073) remained significant (P=0.003) after correction for multiple testing. When combining the P values in the proximal region of MCHR1, the region-wise P value was low (P=0.009) supporting that variations in this part of the gene is associated with schizophrenia. Furthermore, the association was stronger in patients responding to conventional and atypical antipsychotic medication except clozapine.
Conclusion: Our results suggest that MCHR1 may influence schizophrenia susceptibility, in particular among men and patients responding to conventional (nonclozapine) treatment.