Cause dystonia discovered

Apr 10, 2017

Researchers at the University of Liverpool have identified the basis for how a single gene mutation can cause dystonia.

Researchers from the University's Institutes of Translational Medicine (ITM) and Integrative Biology (IIB), led by Dr Nordine Helassa, identified mutations in the gene encoding a protein known as hippocalcin as one cause of the disorder.

The effect of these mutations on the physiological role of hippocalcin or how this would impact on the nervous system had not been understood.

Hippocalcin is a member a family of proteins involved in signalling in the nervous system that have been extensively studied in Professor Bob Burgoyne's group in ITM for the last 20 years.

As a result of their research, which has been published in the journal Human Molecular Genetics, the effect of the disease-causing mutations in hippocalcin on its physiological function have now been characterized.

These mutations do not affect the expression or the structure of the protein but lead to subtle defects in how it controls signalling in neurons.

In the course of the study it was found that hippocalcin can interact with specific types of calcium channels that are important for the normal initiation of neuronal activity and that expression of the disease-causing mutations resulted in overactivation of one particular class of these channels.

Dr Nordine Helassa said: "We can now understand for the first time how these mutations would have important physiological consequences that would lead to abnormalities in neuronal function. Excessive neuronal activation that could result in aberrant signalling in the brain of affected individuals."

Professor Burgoyne added: "These findings provide a clue toward the development of a potential new treatment as it is possible that use of drugs that inhibit the key calcium channels regulated by hippocalcin could help reduce the impact of the inherited disorder."

Full text of the paper -- 'Biophysical and functional characterization of hippocalcin mutants responsible for human dystonia' -- can be found here https://doi.org/10.1093/hmg/ddx133

Source: News Release
University of Liverpool
April 10, 2017