People with schizophrenia have more rare genetic mutations

10 Jul

Schizophrenia is a common, complex disorder that appears to arise from a number

of factors, some of which are genetic. Now, a new study of the genetic mutations

associated with schizophrenia has deepened our understanding of its genetic


colorful dna
The DNA screening study found that patients with schizophrenia

had more rare variants of genes that code for proteins than people not affected by the condition.

The international study, led by the University of California Los Angeles (UCLA), is

published in the journal Nature Communications.

There, the researchers describe how after screening for hundreds of thousands of

genetic variants in people with and without schizophrenia, they found certain types –

rare mutations that code for proteins – occur more frequently in people with the


First author Dr. Loes Olde Loohuis, of UCLA’s Center for Neurobehavioral Genetics,


“While we cannot point to specific mutations that play a causal role in

schizophrenia, we show that schizophrenia patients collectively have more of these

mutations than unaffected individuals.”

Mutations in genes that code for proteins play a key role in the development of the

brain before birth, notes senior author Roel Ophoff, a professor in psychiatry and human

genetics at UCLA, who adds:

“Our finding further supports the hypothesis that schizophrenia is a disorder that may

originate during the early stages of brain development.”

Schizophrenia is a common disorder characterized by hallucinations, delusions and

disorganization, that can significantly impair quality of life for patients and their

families. In the US, around 2-3 million people have the condition.

Rare coding variants ‘contribute to complex genetic architecture of


Fast facts about schizophrenia

  • Schizophrenia is a condition that affects thinking, feeling and behavior and causes

    people to have abnormal experiences

  • The condition will affect around 1 in every 100 people in their lifetime
  • Contrary to what many believe, people with schizophrenia are rarely violent – they

    are more likely to be victims of violence by others.

Find out more about schizophrenia

For the study, the team used a commercially available DNA screening tool to search for

250,000 coding variants in 1,042 schizophrenia patients from the Netherlands and 961

unaffected individuals.

A coding variant is where a gene or sequence of DNA that contains instructions for

making a protein is slightly altered, thus raising the chance that the associated protein

may cause malfunction in the cell in which it is made.

The results of the DNA screening showed that the patients with schizophrenia

had more of the variants than patients without schizophrenia.

The researchers confirmed these findings in another study group of more than 13,000

people with and without schizophrenia.

Prof. Ophoff says even though we know there is a large genetic component in

schizophrenia, we do not know enough about the underlying biology, and concludes:

“Our research shows that rare coding variants throughout the human genome

also contribute to this complex genetic architecture.”

In discussing their results, the authors also note that the genes containing rare

coding variants “significantly overlap with genes expressed in fetal brain highlighting

the potential involvement of neurodevelopment” in the causes of schizophrenia.

The National Institute of Mental Health funded the research.

This work follows news of another piece of research that Medical News Today

reported recently that offers strong evidence of a

neurological cause of schizophrenia. Writing in the journal Neuron, a team

from the University of Cardiff in the UK describes how they found schizophrenia mutations

interfere with chemical signaling in the brain.

Written by Catharine Paddock PhD