Research Grant - 2008

Neuromuscular Disease Award funded by Alma May George & Michael Rogers Stirling Estates
Nerve excitability in Long QT Syndrome.

Dr Stacey Jankelowitz
Institute of Clinical Neurosciences, Royal Prince Alfred Hospital and University of Sydney

The peripheral nerve, i.e. the nerve in the arm or leg, has various ion channels that may be affected as the primary cause, or as a secondary result, of disease. Changes in these channels may produce the symptoms of disease and/or provide targets for treatment. Long QT syndrome is a cardiac disorder in which patients may have no symptoms, may faint frequently, may have abnormal heart rhythms or experience sudden, unexpected death. Recently, the genes and associated ion channel abnormalities in the heart muscle have been described for long QT syndrome. Similar ion channels exist on the human peripheral nerve but these have not been studied in patients with long QT syndrome.

This study will investigate whether there are changes in ion channel function on the peripheral nerve of patients with long QT syndrome using the techniques of axonal excitability testing. Electrical impulses of variable duration and strength are applied to the nerve in various combinations and at different time intervals. The change in threshold for the required response and the change in the response itself, provide information with respect to the different ion channels along the nerve. Patients with long QT syndrome will be compared with age-matched control subjects to determine the presence of alterations in ion channel function. If changes in ion channel function are detected, further studies will be performed to determine whether these changes are in anyway protective against neurotoxins and disease or whether they increase the susceptibility to peripheral nerve disease.