ABSTRACT
BACKGROUND: Oppositional defiant disorder (ODD) is a behavioral disorder that mainly refers to a recurrent pattern of disobedient, defiant, negativistic and hostile behaviors toward authority figures. Previous studies have showed associations of serotonin transporter (5-HTT) and monoamine oxidase A (MAOA) with behavioral and psychiatric disorders. The purposes of this study were to investigate the potential association of 5-HTT gene promoter polymorphism (5-HTTLPR) and MAOA gene polymorphism with susceptibility to ODD in a Han Chinese school population. METHODS: The 5-HTTLPR gene polymorphism and the MAOA gene polymorphism were genotyped in a case-control study of 257 Han Chinese children (123 ODD and 134 healthy controls). RESULTS: There was significant difference in the allele distribution of 5-HTTLPR (χ2 = 7.849, P = 0.005) between the ODD and control groups. Further, there were significant differences in genotype (χ2 = 5.168, P = 0.023) and allele distributions (χ2 = 10.336, P = 0.001) of the MAOA gene polymorphism that is variable-number tandem repeat (MAOA-uVNTR) between two groups. Moreover, there were significant differences in genotype (χ2 = 4.624, P = 0.032) and allele distributions (χ2 = 9.248, P = 0.002) of MAOA-uVNTR only in the male ODD and healthy groups. CONCLUSIONS: Our results suggest that 5-HTTLPR and MAOA-uVNTR gene variants may contribute to susceptibility to ODD. Further, MAOA-uVNTR gene polymorphism may play a role in susceptibility to ODD only in male children.
Subject(s)
Asian People/genetics , Attention Deficit and Disruptive Behavior Disorders/genetics , Monoamine Oxidase/genetics , Polymorphism, Genetic/genetics , Promoter Regions, Genetic/genetics , Serotonin Plasma Membrane Transport Proteins/genetics , Asian People/ethnology , Attention Deficit and Disruptive Behavior Disorders/diagnosis , Attention Deficit and Disruptive Behavior Disorders/ethnology , Case-Control Studies , Child , Female , Genetic Association Studies/methods , Humans , Male , Population Surveillance/methodsABSTRACT
BACKGROUND: Oppositional defiant disorder (ODD) is a behavioral disorder of school-age population. It is well known that 5-HT dysfunction is correlated with impulsivity, which is one of the common characteristics of ODD. The enzyme tryptophan hydroxylase-2 (TPH-2) synthesizes 5-HT in serotonergic neurons of the midbrain raphe. The purposes of this study were to investigate the potential association of TPH-2 polymorphisms with susceptibility to ODD in a Han Chinese school population. METHODS: Four polymorphisms (rs4570625, rs11178997, rs1386494 and rs7305115) of the TPH-2 gene were analyzed by using polymerase chain reaction and DNA microarray hybridization in a case-control study of 276 Han Chinese individuals (124 ODD and 152 controls). RESULTS: In single marker analyses,there was a significant difference in the genotype (χ 2 = 4.163, P = 0.041) and allele frequency (χ 2 = 3.930, P = 0.047) of rs1386494 between ODD and control groups. Haplotype analyses revealed higher frequencies of haplotypes TA (rs4570625-rs11178997), TAG (rs4570625-rs11178997-rs1386494), TAA (rs4570625-rs11178997-rs7305115) and TAGA (rs4570625-rs11178997-rs1386494-rs7305115), but lower frequencies of haplotypes GA (rs4570625-rs11178997) and GAG (rs4570625-rs11178997-rs1386494) in ODD compared to control groups. CONCLUSIONS: These findings suggest the role of these TPH-2 gene variants in susceptibility to ODD. Some haplotypes might be the risk factors for Chinese Han children with ODD, while others might be preventable factors.