Scientists from Cambridge University in the UK have found a common DNA sequence in children suffering from brain tumours. The knowledge is vital to our understanding of one of the least understood genetic disorders.
Pilocytic astrocytomas are amongst the most common brain tumours in children. They are generally benign and tend to occur in the cerebellum, brainstem and optic pathways, though they can also be found at other sites in the brain. As with many other brain tumours, not much is known about the cause, but a genetic basis has long been suspected, making this another genetic disorder that is slowly revealing its secrets.
Genetic Disorders and Brain Tumors
To hunt out the genes that may cause a genetic disorder, scientists compare the DNA of affected persons to see if there is a common DNA sequence. Once found, strong weight is given to that DNA sequence being a contributing factor. Sometimes for further clarification the DNA is compared with the genomes of healthy people. If this DNA sequence is not present in healthy control samples it's another good indicator that it may have something to do with the genetic disorder under study.
Scientists from Cambridge University in the UK, led by Professor Peter Collins found an unusual DNA sequence amongst many of the genomes of the 44 pilocytic astrocytomas they studied. The DNA sequence had become rearranged, in fact it was a fusion of two genes. This was the first time such a hybrid gene had been seen in brain tumours.
How this fusion gene causes the tumour is not known at this stage. But what scientists now have is something they can work with; future research can take a look at the basic genetics and see what protein products are being turned off or incorrectly made.
Detecting Brain Tumors
If this hybrid gene turns out to be a definitive marker for the condition, it opens up the possibility of early detection. That's one of the hopes of Professor Collins as he recently told the British Broadcasting Corporation (BBC). "If we can diagnose exactly which type of brain tumour a child has as early as possible, the tumour is more likely to be treated successfully." And of course once a gene has been implicated in a genetic disorder, new routes for treatments are opened up, such as blocking the action of the gene, and in this case stopping a tumour from growing.
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