Association of 14 polymorphisms in the five candidate genes and attention deficit hyperactivity disorder / 中国当代儿科杂志

<p><b>OBJECTIVE</b>Attention deficit hyperactivity disorder (ADHD) is one of the most common behavior disorders in childhood and adolescent. The etiology of ADHD is unknown. The aim of this study was to investigate the relationship between each of the 14 polymorphisms in the five candidate genes and ADHD, and between the combination of some polymorphisms in those genes and ADHD, in attempting to examine whether combinations of genotypes would confer a significant susceptibility to ADHD.</p><p><b>METHODS</b>One hundred and thirty-nine children with ADHD and one hundred and nineteen normal children were enrolled. Eight single nucleotide polymorphisms (SNP) of three candidate genes were examined with PCR and RFLP techniques. 48 bp VNTR in DRD4 gene was examined with PCR, nondenaturing polyacrylamide gel electrophoresis and silver staining. Five microsatellites (MS) of three candidate genes were examined with genotyping. The relationship between the combinations of 12 polymorphisms and ADHD was examined with logistic regression analysis.</p><p><b>RESULTS</b>1.The frequency of 1065T/1065T genotype and the 1065T allele were significantly higher in ADHD children than that in normal controls (P<0.05). The frequency of -48G/-48G genotype of the A-48G polymorphism of DRD1 gene was significantly lower in ADHD children than that in normal controls (P<0.05). 2. A specific combination of three polymorphisms in the two genes showing an association with ADHD gave a prediction level of 77.5%.</p><p><b>CONCLUSIONS</b>The T1065G polymorphism in the SNAP-25 may be associated with ADHD. The 1065T/1065T genotype and the 1065T allele may be a risk factor for ADHD. The A-48G polymorphism of DRDI may be associated with ADHD. The -48G/-48G genotype may be a protective factor for ADHD. The specific combination of three sites of SNP in SNAP-25 gene and DRDI gene is found and shows an association with ADHD in 12 polymorphisms of the five candidate genes on glutamatergic/dopaminergic pathway.</p>

Distribution of genotype and allele frequencies of dopamine D4 receptor gene 48 bp variable number tandem repeat polymorphism in Chinese Han population in Hunan / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the distribution of genotype and allele frequencies of the dopamine D4 receptor(DRD4) gene exon 3 48 bp variable number of tandem repeats polymorphism in Hunan Han population.</p><p><b>METHODS</b>The genotype and alleles of 304 healthy persons were examined with polymerase chain reaction, denaturing polyacrylamide gel electrophoresis and silver staining.</p><p><b>RESULTS</b>Seven alleles and twelve genotypes were found. The most common allele was allele 5 with a frequency of 70.6%. There was statistically significant difference in allele distribution between the Hunan Han population and the Han population of other regions such as Shanghai, Beijing and Sichuan in China (P< 0.05). Different allele frequency distributions were observed when compared to other ethnic populations such as Japanese, American, Mexican, and Italian (P< 0.05).</p><p><b>CONCLUSION</b>The distributions of allele of DRD4 gene exhibit regional and ethnic heterogeneity.</p>