Researchers at Duke University Medical Center have now discovered that mutations in one gene cause the disease in the majority of patients with a diagnosis of AHC, and because of the root problem they discovered, a treatment may become possible.
The study was published online on July 29 in Nature Genetics.
AHC is almost always a sporadic disease, which means that typically no one else in the family has the disease, said Erin Heinzen, Ph.D., co-author of the study and Assistant Professor of Medicine in the Section of Medical Genetics. "Knowing that we were looking for genetic mutations in children with this disease that were absent in the healthy parents, we carefully compared the genomes of seven AHC patients and their unaffected parents. When we found new mutations in all seven children in the same gene we knew we had found the cause of this disease."
All of the mutations were found in a gene that encodes ATP1A3, one piece of a key transporter molecule that normally would move sodium and potassium ions across a channel between neurons (nerve cells) to regulate brain activity.
In a remarkably broad international collaborative effort, the authors partnered with three family foundations (USA, Italy and France), including scientists from 13 different countries, to study an additional 95 patients and showed over 75 percent had disease-causing mutations in the gene for ATP1A3.
"This study is an excellent example of how genetic research conducted on a world-wide scale really can make a difference for such a rare disorder as AHC," said Arn van den Maagdenberg, Ph.D., and co-author on the study and geneticist from Leiden University Medical Centre in the Netherlands. "It truly was an effort from many research groups that led to this remarkable discovery."
"This kind of discovery really brings home just what the human genome project and next-generation sequencing have made possible," said David Goldstein, Ph.D., Director of the Duke Center for Human Genome Variation and co-senior author on the study. "For a disease like this one with virtually no large families to study, it would have been very difficult to find the gene before next-generation sequencing."
"Ideally what you want from a study like this is a clear indication of how the mutations change protein function so you know how to screen for drugs that will restore normal function or compensate for the dysfunction," said Goldstein, who is also a Professor in Duke Molecular Genetics and Microbiology. "While there is considerably more work to do, our initial evaluation of the mutations suggests that they may alter the behavior of the transporter pump as opposed to reducing its activity, as do other mutations in the gene that cause a less severe neurological disease."
Co-senior author Mohamad Mikati, M.D., Professor of Pediatrics and of Neurobiology, and Chief of Pediatric Neurology at Duke, said, "Many years ago my work with other collaborators on a family with this disease proved that AHC can be caused by genetic factors, but until now we did not know the underlying gene abnormality.
"The finding that ATP1A3 mutations cause AHC will increase awareness of the disease and the ability to accurately diagnose patients," Mikati said. "While it may take a while for novel drugs to be developed to better treat this disease, we will see an immediate impact through specific testing for mutations in this gene when we suspect a case of AHC. This direct testing will prevent misdiagnoses that too often have caused patients to be treated with inappropriate medications."
Other authors worked at the University of Utah, Salt Lake City; Università Cattolica Sacro Cuore, Rome; UPMC Univ Paris, INSERM, CNRS and Groupe Hospitalier de la Pitié-Salpêtrière, in Paris; Leiden University Medical Centre, Leiden, The Netherlands; University of Melbourne, Melbourne, Australia; University Hospitals of Lyon, France; University of Chicago, Illinois; University of California, San Francisco; Rijnland Hospital, Leiderdorp, The Netherlands; Sydney Children's Hospital, Randwick, and University of Sydney, New South Wales, Australia; Royal Hobart Hospital, Hobart, Australia; Our Lady's Children's Hospital, Crumlin, and the Childrens University Hospital, Dublin, Ireland; Rigshospitalet, University of Copenhagen; CRNL, CNRS INSERM, in Lyon, France; and UCL Institute of Neurology, London.
The study was funded by the Center for Human Genome Variation, the Alternating Hemiplegia of Childhood Foundation, the ENRAH for SMEs Consortium grant of the European Commission Research Programme, Association Française de l'Hémiplégie Alternante, A.I.S.EA Onlus, CMSB within the Netherlands Genomics Initiative, the Wellcome Trust, and the University of Utah.
Mary Jane Gore | EurekAlert!
How brains surrender to sleep
23.06.2017 | IMP - Forschungsinstitut für Molekulare Pathologie GmbH
A new technique isolates neuronal activity during memory consolidation
22.06.2017 | Spanish National Research Council (CSIC)
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
23.06.2017 | Physics and Astronomy
23.06.2017 | Physics and Astronomy
23.06.2017 | Information Technology