More on genes from China

I reported on this genetics article from China, now published in a Western journal: J Hum Genet. 2009 Jul 10 which should increase our confidence in its quality. The research suggests a link between genes active in the dopamine (a brain chemical) system and stuttering. Dopamine acts on the connections between neurons in two ways via the level of dopamine and via the level of dopamine receptors that modulate the dopamine level. Jerry Maguire suggests to me that the result

helps to support their dopamine hypothesis of stuttering that an over activity at D2 receptors contributes to stuttering. Many of our successful medications specifically target the D2 receptor i.e. risperidone, olanzapine, aripiprazole and others.

I also emailed Dennis Drayna but he didn't reply.

Here is the abstract:

Association between dopaminergic genes (SLC6A3 and DRD2) and stuttering among Han Chinese.

Lan J, Song M, Pan C, Zhuang G, Wang Y, Ma W, Chu Q, Lai Q, Xu F, Li Y, Liu L, Wang W.

Department of Genetics, College of Life Sciences, Graduate University of Chinese Academy of Sciences, Beijing, PR China.

Normal function of the dopaminergic system is necessary for speech fluency. There was evidence that the activities of dopamine transporter (DAT) and dopamine D2 receptor (DRD2) could be altered in people with speech disfluency. This study aims to ascertain the possible correlation between two dopaminergic genes (SLC6A3 and DRD2) and disorder of speech fluency, and to determine the allelic frequencies of the five single-nucleotide polymorphisms (SNPs) (rs2617604, rs28364997, rs28364998 in SLC6A3 and rs6275, rs6277 in DRD2) among Han Chinese patients with this disorder. A sample of 112 patients with speech disfluency and 112 gender-matched controls were included in this case-control study. The results show that the presence of C allele at rs6277 in DRD2 gene is associated with increased susceptibility to the disorder, whereas T allele is protective. Haplotype 939T/957T is also a protective factor. Journal of Human Genetics advance online publication, 10 July 2009; doi:10.1038/jhg.2009.60.