Scientists have developed a new method for measuring a particular mutant protein that builds up in the nervous system of patients, a causal factor in progression of Huntington’s disease.
Huntington’s disease is a progressive neurodegenerative disease caused by a mutation in the gene that encodes Huntingtin. The Huntingtin gene is located on chromosome four and it follows a dominant inheritance pattern – only one copy of the gene is required for the disease to occur. The mutation is an expansion of triplet repeats in the genetic code. The mutant protein forms aggregates with one another that interrupt neuronal function and transport of messengers in the brain. This leads to dementia, psychiatric disorders and chorea – an involuntary twitching and jerking movement symptom.
Previously it has not been possible to quantify the amount of the mutant protein in patients. However, a team of scientists from UCL, IRBM Promidis, University of British Columbia and CHDI Foundation have now developed a means of detecting the protein from cerebrospinal fluid, a system called the Singulex SMC Technology Erenna Immunoassay. The basic principle of the test is using fluorescent antibody tags to the protein and a laser detection chamber to count the protein molecules.
Dr Edward Wild of UCL Institute of Neurology said: “We think the mutant huntingtin is being released into the CSF from the very brain cells it is killing”.
He added: “It may be a smoking gun that reflects the harm the protein is doing in the living human nervous system”.
It is hoped that this method of detection will aid patients, as new therapeutics are looking at lowering Huntingtin, as amounts of mutant Huntingtin has been shown to increase as the disease progresses. Dr Douglas Macdonald at CHDI has said: “Measuring the amount of huntingtin may also be an essential biomarker for the upcoming trials of huntingtin-lowering therapeutics”.
Whilst this development is not a directly advancing promise of a cure for this terminal disease, it will greatly improve research and clinical trials, indirectly increasing our knowledge of the disease progression.