What new and developing genetic techniques are used to study familial hemiplegic migraine?
Dr. Lyn Griffiths uses the latest genetic technology to discover genes causing familial hemiplegic migraine.
“There's now several genes that are involved in familial hemiplegic migraine, and by ‘involved’ we mean that if they have a mutation, they definitely have the disease. So it's not susceptibility. It's not maybe. It's not increasing your risk. It's definite. And if you know that, then you can treat the people the right way. There are some good treatments for this too.
“So, what we do is we investigate all of those genes and that can get very expensive; however, technology is really getting better and in the last few years there's a new method of technology to sequence genes, and it's called next-generation sequencing. Sounds catchy, sounds exciting, but it really is. It's a lot faster. It's very efficient. It saves more time, not just time, but it’s also cost-effective, as well. So in the last few years we've come up with a method where we can look at all of those genes at once, plus any genes that relate to similar symptoms. And so we've come up with a panel of genes that allows us to look at all of these at once, and in a very timely fashion we can look at them all and provide advice back to the doctor and the patient, now, on those genes. And we can do it all in a few weeks, and for a reasonable amount of money compared to what it would have been. So it's a really great advantage in terms of diagnosis. But more importantly, now that we've been able to do that, we now know that people who have FHM (familial hemiplegic migraine) symptoms, the genes that we know don't cover all of those cases. It probably only covers about 25 to 30% of cases. So what this means is we can get samples from children, adolescents, adults with these severe symptoms, we test all of the genes that we know are implicated in these, and they'll come out negative in about 70% of cases.
“So what this means is, there must be other genes. And so what we're doing at the moment, and this is exciting for us, is that we're now looking at our bank of 1,200 samples but we're looking specifically at the FHM-negative ones and we've started doing whole-genome approaches to identify new genes. So we're currently doing what's called whole-exome sequencing. In Australia, NHMRC is the main funding body for this sort of work that happens with medical research and, luckily, NHMRC has funded this work starting this year. So we're just starting going through all of the FHM samples that we have to try and identify novel genes.
“We've now started going through a number of those and already we've got what we think are some positive new genes. And these are not just risk genes — these are causal genes. Genes that cause these disorders. And so more than anything, this is really good for diagnosis, but it also gives us some really good hints about new treatments, as well, that we should be looking at. So now we've got new genes we can look at, ‘Aha, how do we actually start to affect that particular gene in terms of a treatment?’ as well. So, I think that's my big exciting bit at the moment.”
Familial hemiplegic migraine (FHM) is a subtype of migraine with aura that can have an onset at an early age and cause severe symptoms. Determining the causative genes for FHM can help with diagnosis and treatment. New genetic techniques are cheaper and more powerful than in the past, and are speeding the discovery of FHM genes.
Professor Lyn Griffiths, PhD, BSc Hons
Director, Centre for Genomics & Personalised Health
Queensland University of Technology, Australia
Professor Lyn Griffiths is the executive director of the Institute of Health and Biomedical Innovation, the largest interdisciplinary research institute at Queensland University of Technology. An active and respected molecular geneticist with more than 28 years of experience studying human complex gene disorders, with specific expertise in human gene mapping and gene expression analysis in migraine, cardiovascular disease, and several types of cancer. Professor Griffiths leads the Genomics Research Centre, in which the main focus of research is the identification of genes involved in common human disorders and the translation of this research into new diagnostics and therapeutics.
Professor Griffiths’ own genetics research has appeared in more than 350 peer-reviewed international journals and led to diagnostic breakthroughs for several neurogenetic disorders, including familial migraine, ataxia, epilepsy, and hereditary stroke. A fellow of the Queensland Academy of Arts and Science, Professor Griffiths has also established several significant international collaborations with the Texas Biomedical Research Institute, Oxford University, University of Vienna, the Italian National Research Council, the MS ANZgene Consortium, and the International Migraine Genetics Consortium.