KCNH2 and Prolonged QT interval: These observations suggest that the manifestation of Long QT syndrome associated with this KCNH2 variant exhibits incomplete penetrance influenced by gender within this family, indicating potential protective mechanisms against the syndrome in females affected by this variant.<h4>Conclusion</h4>Our investigation has led to the identification of a novel pathogenic <i>KCNH2</i> variant responsible for Long QT syndrome within a familial context characterized by gender-selective, incomplete penetrance.