AsianScientist (Jun. 30, 2016) – Researchers in Japan have identified significantly more DNA sequence repeats in patients with schizophrenia than in control individuals, outlining a possible link between genome instability and the disease.
Variations in the number of DNA sequence repeats are known to exist between individuals. Some of these copy number variations (CNVs) are associated with disease, as with schizophrenia. In this case, rare CNVs on chromosomes, including 1, 15, 16 and 22, are more common among patients than among controls.
However, previous studies have not fully investigated the effect of particular CNVs on patient characteristics, or examined the genes responsible for CNVs in schizophrenia.
The research team, centered at Nagoya University, used a technique based on DNA fragments labeled with different fluorescent markers to reveal high levels of genetic heterogeneity—whereby several different genetic defects can cause the same symptoms—in schizophrenia. They also observed that the CNVs associated with schizophrenia were in genes controlling the repair of DNA damage.
Significantly more clinically important CNVs were seen in the DNA of almost 1,700 patients with schizophrenia than in the 824 control individuals. Abnormal numbers of X chromosomes were also associated with the disease.
“Patients with clinically important CNVs showed a range of characteristics, such as developmental problems and refusal to accept treatment,” said Assistant Professor Itaru Kushima, the first author of the study.
The researchers looked closely at the genetic regions containing CNVs to identify several gene categories associated with schizophrenia that may be affected by genetic disturbance. These include oxidative stress response, which leads to DNA damage when imbalanced, and genomic integrity, involving DNA repair and replication.
Their findings are published in Molecular Psychiatry.
The article can be found at: Kushima et al. (2016) High-Resolution Copy Number Variation Analysis of Schizophrenia in Japan.
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Source: Nagoya University; Photo: Shutterstock.
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