For all the progress medicine has made is the past 250 years, the profession is still much akin to that of an auto mechanic: a motorist comes in complaining of some problem, and the mechanic knocks, pokes, and listens, trying to figure out what is amiss.
Yet, until the completion of the Human Genome Project, in 2000, physicians relied almost exclusively on the physical manifestation of a condition to tack a diagnosis-a very hit-and-miss proposition.
“If you look at the individuals who present themselves at the clinic, … only 30 per cent of patient ever leave the clinic even with a diagnostic,” said Dr. Mansoor Mohammed, chief scientific officer at Combimatrix Molecular Diagnostics (CMDX), a biotech start-up based in Irvine, California. “Seventy per cent of patients will actually then leave the clinic without a clue as to what the diagnosis is.”
Enter “personalized medicine.” A technology called array comparative genomic hybridization (CGH), promises -from detecting congenital conditions in newborns to the classification of tumours in older individuals. Mohammed described the potential of array CGH at an emerging technologies event held Monday morning at the Mars Discovery District.
The point of array CGH is to find changes such as deletions or amplifications in a subject’s DNA test sample, which are indicative of cancer risks. It does so by comparing the relative number of copies of a certain chromosome, in the DNA test sequence with the number of copies of the same in a stretch of generic DNA. Drastic differences in the two show up as bright spots of red or green, giving an indication of DNA gains and losses.
The industry leader, Signature Genomics, based in Spokane, Washington, offers an array CGH test to the public for US$1,600 a pop, which can test for anomalies among 126 different genes. Now Mohammed’s company, CMDX is in the process of setting up a new venture, Genomic Portraits Inc., a majority-owned Canadian company that will soon set up shop in the Mars discovery building. It plans to offer the diagnostic test in Toronto as early as July, for about US$1,000, according to Mohammed.
Advances in the manufacturing of the array, the printing the slides, and competition-due to rising demand-are driving down prices. “I would like to see the test come down during the next two to three years to US$600 or US$700,” said Mohammed. That price level, he added, will remove more people’s financial constraints for not taking the test.
