OBJECTIVE: Consistent evidence indicated that aberrant DNA methylation may be 
involved in the development of schizophrenia. DNA methyltransferase 3B (DNMT3B) 
is the key methyltransferase in DNA methylation regulations. In this study, we 
investigated the association between DNMT3B polymorphisms and the susceptibility 
of early onset schizophrenia in Chinese Han population.
METHODS: Case-control (patients=381 and controls=472) and family based 
(trios=103) study was performed through genotyping two tag single nucleotide 
polymorphisms (rs2424908 and rs6119954) covering the whole DNMT3B gene. Single 
nucleotide polymorphism association and haplotype analysis were performed.
RESULTS: The frequency of G allele of rs6119954 was significantly higher in 
patients than that in controls (P=0.017). Genotype distribution of rs6119954 was 
significantly different between patients and controls (P=0.046). A 
haplotype-wise analysis revealed a higher frequency of the T-G 
(rs2424908-rs6119954) haplotype in patients than that in controls (P=0.033). In 
the transmission disequilibrium test analysis, G allele of rs6119954 was 
preferentially transmitted in the trios (P=0.030).
CONCLUSION: Our findings indicate that DNMT3B may be a candidate gene for 
susceptibility to early onset schizophrenia.