Principal Investigator: Dr Anwar Chahal
Mayo Clinic (USA)Tags: 48286, cardiovascular, channelopathy, SADS, seizure, SIDS, SUDEP
Both brain and heart require precise electrical activity to function correctly. Appropriate electrical activity in the brain is needed for sensing the world around us, interacting with it, and conscious thought amongst other things. Abnormal electrical activity can cause disease. For example, in epilepsy, abnormal electrical activity manifests as seizures. Seizure symptoms can range from uncontrollable limb shaking with loss of consciousness to sensing smells, tastes or touches which are not present. One of the major worrisome complications of epilepsy in Sudden Unexplained Death in Epilepsy (SUDEP). SUDEP is when a person with epilepsy dies suddenly and no explainable cause can be found. SUDEP affects around 500 people every year in the UK. The causes of SUDEP are poorly understood.
Appropriate electrical activity in the heart is required for it to contract effectively and pump blood efficiently. Abnormal electrical activity disorders are known as arrhythmias. Sudden cardiac arrest occurs when the heart suddenly stops pumping blood around the blood and is highly fatal. Numerous risk factors for sudden cardiac arrest have been identified. Many of these are inherited defects (gene mutation) in components of the heart’s electrical conduction system.
The inner workings of the electrical conduction systems of heart and brain are very similar and interestingly there appears to be an overlap between diseases affecting each system. For example, several heart arrhythmias can present with seizure-like activity and epilepsy is considered a risk factor for sudden cardiac arrest. A series from Australia used post-mortem target-panel gene testing and identified pathogenic variants associated with long QT syndrome (a condition associated with sudden death) in over 20% of cases. These findings have not been reproduced and reported from other centres. This raises the question of whether causes of SUDEP are similar to the known causes of sudden cardiac arrest. To address this, we would like to test whether patients with epilepsy have known gene mutations implicated in sudden cardiac arrest at a greater level than patients without epilepsy. If this is found to be true, we would like to know which gene mutations in particular are present.
Identifying causes of SUDEP could be an important first step in identifying patients at risk from this condition and potentially devising preventative treatments in the future.