Same family, same mutation, different ECG

Background: Different types of long QT syndromes (LQTS) have distinct ECG manifestations according to the type and magnitude of ion channel dysfunction. While LQT1 carriers usually have broad-based T waves and LQT3 carriers have extended ST segments with relatively narrow peaked T waves; LQT2 carriers have low-amplitude T waves with high incidences of notches.

Methods: We describe three members of a family with the same LQTS2 pathogenic variant, but different surface ECG findings.

Conclusion: This case shows ECG differences may also occur between family members who have pathogenic variants associated with long QT syndrome.