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Headlines 5 The promise of GENE EDITING M ost people have never heard of it. Few can even pronounce it. And, confusingly, it has nothing to do with teeth. Pronounced shahr-koh-marie-tooth, it’s named after the three physicians who first described it back in the 1800s: Dr Jean-Martin Charcot and Dr PierreMarie (both fromFrance) and Howard Henry Tooth (of the United Kingdom). An inherited disorder involving disease- causing variants in over 100 different genes, it affects the peripheral nervous system – the nerves outside of the brain, with symptoms in the limbs, and potentially the ears. The progressive disease causes loss of movement and sensation in the hands, feet, arms and legs, balance problems, and sometimes deformities such as hammer toes, high arches and curled fingers. In most cases, the ankle weakness leads to problems with walking. In extreme cases, patients need wheelchairs and can’t use their hands properly. At the University of Auckland’s School of Biological Sciences, a team of neuroscientists is studying families who have CMT, but the usual genetic tests done through the health system have been unable to find the genetic abnormality that causes their condition. Dr Whitney Whitford, the Principal Investigator, says, “The potential to find novel genes and mutations will really help increase understanding of CMT. Also, studying rare diseases helps us understand fundamental biology and may even help us learn more about common diseases that involve the same pathways.”  So far, Whitney has sequenced the DNA of seven families, pinpointing the variant for one, with another two potential variants in two other families being investigated further. Her results will provide much-needed answers for the families, and improve the ability to diagnose relatives. Scientists have been working on gene therapies since the mapping of the human genome in 1990. Thanks to more recent advances in DNA sequencing and gene editing technology, gene therapy is now on the verge of revolutionising medicine. The technique involves modifying a person’s faulty gene/s to cancel out a disease. Rather than simply treating a disease, it could eliminate it altogether. “Once we’ve identified the causative gene for an individual, depending on the mutation, CMT has the potential to be a great target for gene therapy,” says Whitney. At the moment, gene-editing is largely available only to patients taking part in clinical trials. Long term, Whitney hopes a human trial of gene editing can be undertaken for New Zealand for CMT patients. Only one in 6500 New Zealanders has the genetic disease Charcot-Marie-Tooth (CMT). As with many rare disorders, living with CMT can be incredibly isolating for families. Photo credit: Dr Charlotte Johnson continued on page 6 “Once we have identified the causative gene for an individual, depending on the mutation, CMT has the potential to be a great target for gene therapy.” Dr Whitney Whitford