Child and Adolescent Psychiatry Community Partnership Unit, Nagasaki University Hospital, Nagasaki, Japan.
Unit of Translation Medicine, Department of Neuropsychiatry, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
J Neural Transm (Vienna). 2020 Nov;127(11):1501-1515. doi: 10.1007/s00702-020-02188-w. Epub 2020 Apr 13.
Twin studies of psychiatric disorders such as schizophrenia and autism spectrum disorder have employed epidemiological approaches that determine heritability by comparing the concordance rate between monozygotic twins (MZs) and dizygotic twins. The basis for these studies is that MZs share 100% of their genetic information. Recently, biological studies based on molecular methods are now being increasingly applied to examine the differences between MZs discordance for psychiatric disorders to unravel their possible causes. Although recent advances in next-generation sequencing have increased the accuracy of this line of research, there has been greater emphasis placed on epigenetic changes versus DNA sequence changes as the probable cause of discordant psychiatric disorders in MZs. Since the epigenetic status differs in each tissue type, in addition to the DNA from the peripheral blood, studies using DNA from nerve cells induced from postmortem brains or induced pluripotent stem cells are being carried out. Although it was originally thought that epigenetic changes occurred as a result of environmental factors, and thus were not transmittable, it is now known that such changes might possibly be transmitted between generations. Therefore, the potential possible effects of intestinal flora inside the body are currently being investigated as a cause of discordance in MZs. As a result, twin studies of psychiatric disorders are greatly contributing to the elucidation of genetic and environmental factors in the etiology of psychiatric conditions.
精神障碍（如精神分裂症和自闭症谱系障碍）的双生子研究采用了流行病学方法，通过比较同卵双胞胎（MZ）和异卵双胞胎的一致性率来确定遗传率。这些研究的基础是 MZ 共享 100%的遗传信息。最近，基于分子方法的生物学研究越来越多地被应用于检查 MZ 精神障碍不一致的差异，以揭示其可能的原因。尽管新一代测序的最新进展提高了这一研究方向的准确性，但人们越来越重视表观遗传变化而不是 DNA 序列变化，认为这是 MZ 精神障碍不一致的可能原因。由于表观遗传状态在每种组织类型中都不同，除了外周血中的 DNA 外，还正在进行使用死后大脑或诱导多能干细胞诱导的神经细胞中的 DNA 的研究。虽然最初认为表观遗传变化是环境因素的结果，因此不可遗传，但现在已知这些变化可能在代际之间传递。因此，目前正在研究体内肠道菌群可能是 MZ 不一致的原因。因此，精神障碍的双生子研究极大地促进了对精神疾病病因中遗传和环境因素的阐明。
