SNP Shot: Genomic Insights

Wolff-Parkinson-White (WPW) syndrome is a heart condition where abnormal electrical pathways cause an irregular heartbeat, known as an arrhythmia.

A healthy heartbeat relies on precisely timed electrical signals. These signals travel from the heart's upper chambers (atria) to the lower chambers (ventricles) through a specialized group of cells called the atrioventricular (AV) node. The AV node ensures the ventricles contract slightly after the atria.

In individuals with WPW syndrome, an extra electrical connection, called an accessory pathway, is present at birth. This pathway allows electrical signals to bypass the AV node, rapidly transmitting signals from the atria to the ventricles. This pathway can also transmit impulses backwards, from the ventricles to the atria. This abnormal pathway disrupts the heart's coordinated electrical activity, potentially leading to a rapid heart rate (tachycardia) and other rhythm disturbances. Symptoms can include dizziness, heart palpitations (a fluttering or pounding sensation), shortness of breath, and fainting (syncope). Though rare, severe arrhythmias associated with WPW syndrome can lead to cardiac arrest and sudden death. Paroxysmal supraventricular tachycardia is the most commonly observed arrhythmia in WPW syndrome.

WPW syndrome complications can arise at any age. However, some individuals born with an accessory pathway may never experience related health issues.

WPW syndrome is often associated with other heart structural abnormalities or underlying heart disease. A common association is Ebstein anomaly, which affects the tricuspid valve controlling blood flow between the right atrium and right ventricle. Furthermore, WPW syndrome-related heart rhythm problems can be a feature of several genetic syndromes, including hypokalemic periodic paralysis (causing episodes of muscle weakness), Pompe disease (characterized by excess glycogen storage), Danon disease (weakening heart and skeletal muscles, leading to intellectual disability), and tuberous sclerosis complex (resulting in non-cancerous tumor growth in various body parts).

Inheritance:

Most WPW syndrome cases are sporadic, meaning they occur in individuals with no known family history. These cases are not inherited. Familial WPW syndrome, where the condition runs in the family, is uncommon. This familial form typically follows an autosomal dominant inheritance pattern, meaning only one copy of the affected gene is needed to cause the condition. In most instances, individuals with familial WPW syndrome inherit the condition from an affected parent.