Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Review
. 2020 Nov;127(11):1501-1515.
doi: 10.1007/s00702-020-02188-w. Epub 2020 Apr 13.

Genetic and environmental factors of schizophrenia and autism spectrum disorder: insights from twin studies

Akira Imamura  1 , Yoshiro Morimoto  2   3 , Shinji Ono  3 , Naohiro Kurotaki  4 , Shinji Kanegae  5 , Naoki Yamamoto  5   2 , Hirohisa Kinoshita  2 , Takahiro Tsujita  6 , Yuji Okazaki  7   8 , Hiroki Ozawa  5   2
Affiliations
Review

Genetic and environmental factors of schizophrenia and autism spectrum disorder: insights from twin studies

Akira Imamura et al. J Neural Transm (Vienna). 2020 Nov.

Abstract

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.

Keywords: Autism spectrum disorder; Epigenetics; Psychiatric disorders; Schizophrenia; Twin study.

PubMed Disclaimer

Conflict of interest statement

The authors declare that they have no conflict of interest.

Figures

Fig. 1
Fig. 1
Concordance rate of MZs and DZs for various disorders. Originally cited and published in the study of Schumacher and Petronis (2006). We have added data on ADHD (Pingault et al. 2015) to the original graph that is pictured here
Fig. 2
Fig. 2
Heritability and shared environmental factor. This figure cites and was created based on the study by Hrubec and Neel (1981)
See this image and copyright information in PMC

References

    1. Åberg K, Saetre P, Jareborg N, Jazin E. Human QKI, a potential regulator of mRNA expression of human oligodendrocyte-related genes involved in schizophrenia. Proc Natl Acad Sci USA. 2006;103(19):7482–7487. doi: 10.1073/pnas.0601213103. - DOI - PMC - PubMed
    1. American Psychiatric Association . Diagnostic and statistical manual of mental disorders, Fifth edition (DSM-5) Philadelphia: American Psychiatric Association; 2013.
    1. Asperger H. Das psychisch abnorme Kind. Wien Klin Wochenschr. 1938;51:1314–1317.
    1. Asperger H. Die 'Autistischen Psychopathen' im Kindesalter. Archiv fur Psychiatrie und Nervenkrankheiten. 1944;117:76–136.
    1. Besteher B, Brambilla P, Nenadić I. Twin studies of brain structure and cognition in schizophrenia. Neurosci Biobehav Rev. 2020;109:103–113. doi: 10.1016/j.neubiorev.2019.12.021. - DOI - PubMed