Nicotinamide-N-methyltransferase (NNMT) in schizophrenia: Genetic association and decreased frontal cortex mRNA levels

Abstract

Emerging evidence suggests impaired one-carbon metabolism in schizophrenia. Homocysteine is one of the key components of one-carbon metabolism. Elevated plasma homocysteine levels were reported in schizophrenia. A linkage study found that nicotinamide-N-methyltransferase (NNMT), an enzyme involved in one-carbon metabolism, is a determinant of plasma homocysteine levels. In an association study the rs694539 NNMT single nucleotide polymorphism (SNP) was found significantly associated with hyperhomocysteinaemia. Aiming to assess the possible involvement of NNMT in the aetiology of schizophrenia we (1) performed an association study of eight NNMT tagged SNPs in 202 families sharing the same ethn..