In the western world it affects mainly young and middle-aged adult men. It has been associated with mutations in the same sodium channel that is affected in long QT syndrome, but this appears to account for only 1 in every 5 people with the condition. The sodium channel behaves abnormally in that movement of sodium ions into the cells is restricted. This results in particular changes on the ECG but no abnormalities in the structure of the heart. Other genes have been described as being involved in Brugada syndrome that produce calcium ion channels and a protein in the cell surface (membrane) that interacts with the sodium channel. They have, however, only been detected in a small number of carriers.