Schizophrenia: Researchers Pinpoint Rare Genetic Risk Variants

The research team - comprised of more than 260 scientists across the globe - recently reported their findings in the journal Nature Genetics.

Schizophrenia is a chronic mental disorder characterized by delusions, hallucinations, abnormal thoughts, and agitated body movements.

According to the World Health Organization (WHO), more than 21 million people worldwide are affected by schizophrenia, with the disorder being more common among males than females.

In the United States, schizophrenia is estimated to affect around 3.5 million people, making it one of the leading causes of disability in the country.

In recent years, researchers have been learning more about the genetic causes of schizophrenia. Earlier this year, for example, Medical News Today reported on a study revealing how a variant of a gene called C4 contributes to schizophrenia development. 

Eight genomic regions hold mutations linked to schizophrenia

The team searched the genomes of 41,321 individuals, of whom 21,094 had schizophrenia and 20,227 did not.

The researchers identified eight regions of the genome that possess mutations called "copy number variations" (CNVs) that are associated with increased risk of schizophrenia. In other words, these mutations are significantly more common in people with schizophrenia than those in the general population.

CNVs are copies or deletions of DNA sequences that can affect normal gene functioning, increasing the risk of certain diseases and disorders.

In this study, the CNVs identified by the researchers were shown to increase the risk of schizophrenia development by four- to 60-fold.
 
What is more, these CNVs were found to be more common among genes that play a role in the function of synapses - the structures that connect nerve cells, or neurons, and transmit chemical signals.

The researchers note that only a small percentage of study subjects had the schizophrenia-associated CNVs - around 1.4 percent - showing that these mutations are rare.

Further analyses are needed in order to uncover more rare genetic variants that may increase the risk of schizophrenia, the researchers note, but the current research has made a strong start.

"This study represents a milestone that demonstrates what large collaborations in psychiatric genetics can accomplish.

We're confident that applying this same approach to a lot of new data will help us discover additional genomic variations and identify specific genes that play a role in schizophrenia and other psychiatric conditions."

Jonathan Sebat, Ph.D.

Genetic Link Between Kidney Defects and Neurodevelopmental Disorders

A new study conducted by Columbia University Medical Center, headed by Dr. Gharavi, shows that there is a link between kidney defects and mental illnesses. The study tested 522 children with malformed kidneys and 17% of them carried a CNV that contributed to their kidney disorder. CNV's, short for copy number variations, are extra copies or deletions of DNA that are just large enough to hold several genes. When CNV's are present, the affected gene occurs in a higher or lower dose than normal which can cause health disorders. The CNVs discovered in the study were also linked to developmental delays and mental illnesses, and 1 in 10 of the children had one. Dr. Gharavi said "Though it remains unclear why kidney malformations and neurodevelopment are linked in some cases, it is possible that the same genes involved in kidney development are involved in brain development." From this research they have concluded that nearly 10 percent of children who are born with kidney defects also have large  alterations in their genetic makeup which are linked with neurodevelopmental delay and mental illness.


"This changes the way we should handle these kids," said kidney specialist Ali  Gharavi. "If a physician sees a child with a kidney malformation, that is a warning sign  that the child has a genomic disorder that should be looked at immediately because of the risk of neurodevelopmental delay or mental illness later in  life," he said. This newly discovered linkage can help the start of personalized medical care. Eventually, an evaluation for genomic alterations will be part of the standard clinical workup and patients can recieve a more precise diagnosis. The underlying genetic defect of the patient will dictate what approach to take and what specific medication will work best for that patient.

I think this new dicovery is exactly where we need to be heading to improve our medical treatments. This research helps us group patients with kidney malformations not only into one big group but also into smaller subgroups also based on possible mental disorders. If we can do this for many different diseases then in the future doctors will be able to look at a person's own potential risk for certain illnesses. I think that this new study is intersting because it shows that personalized medicine is in our near future.