Too often the first and final symptom is sudden death.

Other symptoms include:

Light headedness, dizziness, fainting, palpitations, shortness of breath, paleness, head aches.

Symptoms vary according to the type of channel involved, whether the person is male or female, their age, and the length of the QT interval on the ECG. Males are more likely to have symptoms before puberty, while females are more likely to have them in adolescence and early adulthood. Relatives from the same family who have inherited the same mutation may have very different experiences.

Potassium channel:

Associated with sudden death which is related to exercise or when the person has been startled or awoken suddenly, (acoustic trigger).

Sodium channel:

Associated with death while asleep.

There are no physical signs. However, people with Andersen's Syndrome may also have muscle weakness or minor abnormalities of the skull, chin, fingers and toes.

NB: It is also thought that many young adults who have died while driving or swimming may, in fact, have suffered from these genetic defects.

Energy Drinks:

Energy drinks are becoming increasingly popular with young people and can be beneficial with CAUTION: Popular brands 'disguise' their main ingredients, Caffeine as Guarana, green tea extract, coffee extract.  Sugar as natural cane juice and glucose. With added B vitamins, Inositol, ginseng with other additives, this results in extremely high levels of caffeine and sugars that can produce toxic effects:  Headaches, Dizziness, Agitation, Tremor, Palpitation/Tachycardia (abnormal rapid heart rate/ cardiac arrhythmia),  Death.