Tuesday, 15 May 2012

Twin Studies of the Genetics of Schizophrenia
By: Emily Malia      #42876559
Artist Interpretation of Schizophrenia
(Cure, 2011)

The assumption that identical twins are exactly the same in every way, even down to their gene sequence, seems logical. However, recent studies have shown that no-one is exactly the same; everyone has variations hard wired into their genetic code, which makes every person unique. Molecular geneticist Shiva Singh from The University of Western Ontario and psychiatrist Dr. Richard O'Reilly have used this discovery to embark on genetic advances which may possibly result in the identification of the genetic sequence of schizophrenia. (Wallis, 2011).

Schizophrenia is a severe, highly inherited mental illness affecting the normal functioning of the brain. The main symptoms include; hallucinations, altered emotions, intellectual damage and disordered behaviour. (Hywel J. Williams, 2009). The image below shows an MRI scan of the brain of identical twins where only one has the disease. This particular mental illness causes the ventricles to become enlarged. Since schizophrenia is a fairly common disease, it affects around 1% of the world population. (Hywel J. Williams, 2009).

MRI Images of identical twins where only one has schizophrenia
(Schizophrenia.com, 2009)
It was previously believed by many scientists that identical twins had identical genetic material. Therefore, if one twin had schizophrenia then so would the other. However, Singh studied around one million gene sequences of identical twins where only one of the pair had schizophrenia. In fact, “studies over the years have shown that the risk of the disease in both twins is only 50 percent.” That means twins are either not genetically identical or the disease that was once thought hereditary is in fact caused non-genetically. (Singh, 2011).
Identical Twins, they might look similar, but they are completely unique
(Raising Twins, 2012)
By further study of the genetic code of identical twins, Singh and his team have now demonstrated that twins are in fact not genetically identical since there are many variations in their genome. Singh stated,
“By looking at the million DNA differences between these pairs, all of a sudden I realised … these guys have differences. They are not genetically identical. So if they are not genetically identical and schizophrenia is in the genes, then these differences that I look and find must have something to do with the disease.” (Singh, 2011).   Singh discovered that identical twins have about 12 percent of DNA variation. He also concluded that since schizophrenia is a genetic disorder, then somewhere in the 12% difference in the genetic makeup of identical twins with only one diagnosed with the disease, must be located the genes that cause schizophrenia. (Singh, 2011)
Dr. O'Reilly hopes that’s this research will eventually lead to a better understanding of schizophrenia, and possible gene location of the disease. This in turn will result in more effective treatments. "If we had a genetic test for schizophrenia, it could be applied early in the disease when it's hard to make that diagnosis," stated Dr. O'Reilly. (Singh, 2011)

Singh and Dr. O’Reilly’s genome-wide approach is a pioneer. It has the potential to be effective where all other approaches have failed. In fact, this genetic advance may revolutionise medical knowledge and treatments of schizophrenia worldwide!

Reference List

Cure, E. (2011, March 18). The Severity of Schizophrenia. Retrieved March 19, 2012, from Cure Talk: http://trialx.com/curetalk/2011/03/understanding-schizoaffective-disorder-vs-schizophrenia/
David A Collier, E. V. (2009). Advances in the Genetics of Schizophrenia: Will High-Risk Copy Number Variants be Useful in Clinical Genetics or Diagnostics? Medicine Reports, Online Resource.
Hywel J. Williams, M. J. (2009). Schizophrenia Genetics: New Insights From New Approaches. British Medical Bulletin, Online Source.
Raising Twins. (2012). Identical Twins. Retrieved March 19, 2012, from Raising Twins.com: http://www.raising-twins.com/types-of-twins.html
Schizophrenia.com. (2009). MRI Images of Brains of People that Have Schizophrenia . Retrieved March 19, 2012, from Schizophrenia.com: http://www.schizophrenia.com/research/slide10.htm
Singh, S. (2011). Seeing Double (or Triple) in Genome Sequencing. Western News, Online Source.
Wallis, K. (2011). Study To Pinpoint The Genetic Determinants Of Schizophrenia. Medical News Today, Online Source.

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