Psychiatric Disorders: The Search for Genes

Abstract

Psychiatric disorders are common illnesses whose core features include disturbances of mood, perception, cognition and behaviour that cause distress or interfere with daily functioning. Genes contribute substantially to risk, but multiple genes and environmental factors are involved, leading to complex patterns of inheritance. Many genes and genetic markers have already been identified that contribute to schizophrenia, bipolar disorder and autism, but each individual gene plays a small role and much of the inherited risk for these disorders remains unexplained. Most of the identified genetic risk factors are common and each one has a small impact. Some rare genetic variants have also been discovered that have a larger impact on risk, especially for schizophrenia or autism. Ongoing studies are beginning to uncover how multiple genetic risk factors act together in the development of psychiatric disorders, but much more remains to be learned before we can use genetic discoveries to develop better methods of diagnosis and treatment.

Key Concepts

  • Most psychiatric disorders are strongly influenced by genes.
  • Genome‐wide association studies have identified numerous common genetic markers associated with major psychiatric disorders.
  • Each common allele confers little risk, but many add together to confer susceptibility to psychiatric illness.
  • Rare copy number variants, which influence the dosage of many genes, confer substantial risk for schizophrenia, autism spectrum disorders and intellectual disability.
  • Rare, gene‐damaging point mutations, most of which arise de novo, can also confer substantial risk for schizophrenia, autism spectrum disorders and intellectual disability.
  • The ultimate goal of gene identification for mental illness is to develop better methods of diagnosis and treatment.

Keywords: behaviour; psychosis; bipolar disorder; schizophrenia; autism; GWAS

Figure 1. Genome‐wide association study findings in schizophrenia, bipolar and other major psychiatric disorders. Regions harbouring one or more SNPs (single‐nucleotide polymorphisms) with p < 10−7 based on large published GWAS (genome‐wide association studies) are shown by coloured dots. Source: GWAS Catalog, https://www.ebi.ac.uk/gwas, accessed June, 2016.
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Web Links

AlzGene (field synopsis of genetic association studies in Alzheimer disease), http://www.alzgene.org/

GWAS Catalog: The NHGRI‐EBI Catalog of published genome‐wide association studies, https://www.ebi.ac.uk/gwas/

Metamoodics (a bioinformatics resource that synthesises the findings from ongoing genetic studies of mood disorders), http://psychiatry.som.jhmi.edu/metamoodics/

NIMH Repository and Genomics Resource, https://www.nimhgenetics.org/

Psychiatric Genomics Consortium, https://www.med.unc.edu/pgc

Ricopili (a tool for visualising regions of interest in select GWAS data sets), https://data.broadinstitute.org/mpg/ricopili/

SchizophreniaGene (field synopsis of genetic association studies in schizophrenia), http://www.szgene.org/

Sfari Gene (a modular database for autism research), https://gene.sfari.org/autdb/Welcome.do

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How to Cite close
McMahon, Francis J(Jan 2017) Psychiatric Disorders: The Search for Genes. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0005418.pub2]