April 10 (UPI) -- Researchers at the University of Liverpool in England have uncovered how a single gene mutation can cause the rare neurological disorder known as dystonia.
Dystonia is a rare neurological disorder affecting about 70,000 people in the Britain that can occur after an injury or be inherited, and causes progressively worsening uncontrollable muscle contractions and repetitive movements.
The condition ranges from mild to severe, affects different body parts and can cause dragging leg, cramping of the foot, uncontrollable blinking and speech difficulties.
A team at the University's Institutes of Translational Medicine and Integrative Biology identified mutations in the gene encoding a protein called hippocalcin as a cause of the dystonia.
Hippocalcin is part of a family of proteins that signal the nervous system. The mutations do not affect the expression or structure of the protein but cause subtle defects in how it controls signaling in neurons.
Researchers found that hippocalcin can interact with specific types of calcium channels that are vital for the normal initiation of neuronal activity and expression of the disease-causing mutations cause overactivation of one specific class of channels.
"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," Dr. Nordine Helassa, of the Institutes of Translational Medicine, said in a press release.
The study was published in Human Molecular Genetics.