GENOME DIFFERENCE ANALYSIS BETWEEN MONOZYGOTIC TWINS DISCORDANT FOR NEUROPSYCHIATRIC DISORDERS

1997年，我们取得了以下成果：1.我们将RLGS应用于患有颞叶癫痫、双相情感障碍和惊恐障碍的同卵双胞胎的基因组。然而，我们发现患病双胞胎和非患病双胞胎之间没有可复制的RLGS斑点差异。今年，我们发现了一例非常罕见的单卵双胞胎自闭症不协调病例，并在知情同意的情况下采集了血样。我们试图克隆在去年的实验中发现的患有精神分裂症的同卵双胞胎和未受影响的同卵双胞胎之间的RLGS点不同的DNA片段(Tsujita等人，1998年)。在克隆RLGS点之间的人DNA片段时，我们遇到了原有的RLGS方法的困难。我们面临克隆问题的原因是，最初的RLGS需要大量的人血，80ml，并且只含有0.5个饱和摩尔(5*10^-19&gt；)的DNA，而且NotI、PvuII、PstI联合消化的DNA片段有5‘和3’的悬垂末端，这对PCR来说是不方便的。因此，今年我们致力于改进RLGS，使RLGS的DNA含量增加，并减少了克隆所需的人血量。我们已经基本完成了改进的RLGS的开发，并得到了几个RLGS模式。如果我们在同卵双胞胎之间发现不一致的神经精神障碍的不一致点，这种新的改良的RLGS一定会使克隆变得更容易。由首席研究员开发的将基因组扫描与不协调同卵双胞胎相结合的方法可能适用于具有复杂遗传基础的各种疾病的S，在研究基因组机制时，避免同卵双胞胎中的一个成员患上这种疾病，而不是同卵双胞胎避免。

In 1997, we obtained the following results.1. We applied RLGS to genomes from the monozygotic twins discordant for temporal lobe epilepsy, bipolar disorder and panic disorder. However, we found no reproducible RLGS spot difference between affected and non-affected twins. This year, we found a very rare case of monozygotic twin discordant for autism and collected blood samples with informed consents.2. We tried to cloning DNA fragments included in RLGS spots different between affected and non-affected monozygotic twins with schizophrenia that was found in the experiments last year (Tsujita et al., 1998). We faced with difficulties of the original RLGS method in the cloning of human DNA fragment among a RLGS spot. The reasons why we faced with the cloning problems were that the original RLGS required a large amount of human blood, 80ml, and contained only 0.5 satto moles(5*10^<-19>) DNA in average among a RLGS spot that was 1/10^5 less amount than that of DNA usually available for PCR.Moreover, the DNA fragments digested by the combination of NotI, PvuII, PstI had 5' and 3' overhanging ends that were inconvenient for PCR.Therefore, this year we made an effort to develop a modification of RLGS that included PCR process which increased an amount of DNA contained in a RLGS spot and decreased a required volume of human blood for thc cloning. We have almost completed to develop a modified RLGS and got a couple of RLGS patterns. This new modified RLGS must make the cloning easier if we find discordant spots between identical twins discordant for neuropsychiatric disorders.The method developed by principal investigator that combines genome scanning with discordant monozygotic twins may be available for various kind s of disorders with complex genetic basis in the investigation of genomic mechanisms to be avoided suffering from such disorders by one member of a monozygotic twin pair and not to be avoided by the co-twin.