A specific DNA change has been discovered by Linda Brzustowicz which is highly likely to increase the risk of developing schizophrenia in select people. This functional DNA change drastically increases gene expression within the gene NOS1AP(CAPON). Also introduced was a statistical method called Posterior Probability of Linkage Disequilibrium (PPLD) which quantifies the association between the NOS1AP gene in question and schizophrenia. PPLD was used to evaluate a total of 60 variants of the NOS1AP gene or single nucleotide polymorphisms (SNP’s).
Through the use of the introduced PPLD method, the 60 variants were narrowed down to three cases which had a highly increased risk of developing schizophrenia. From here these three candidate single nucleotide polymorphisms were introduced into cultures of cloned brain tissue cells from humans. This was done to measure the quantity of protein which was being produced by each of the three variants termed “overexpression”. Also added to these cultures was a certain gene from which creates the glow of a firefly and human regulatory DNA, these in combination with the SNP would give researches notice of which variant was producing more protein by the intensity of light from the culture. The light is then measured by a luminometer showing that there was a drastic increase in gene expression from one of the three variants. These results rectify that the increased expression of NOS1AP observed in postmortem brain samples of individuals with schizophrenia do indeed give an increased risk of 55 percent within the studied variants.
But in saying this, it is also stated that if you have the altered gene that you will contract schizophrenia, the frequency of the studied variant in the general population is approximately 40 percent, whereas only 1 percent of the population are diagnosed with schizophrenia.
ScienceDaily, May 10, 2009.
http://www.sciencedaily.com /releases/2009/04/090407105154.htm
