The House of Kor was active until 2375, when Kor, who was the last son of the House, died in battle against the Dominion. Kor had no surviving heirs as his son had died at the hands of the Albino in the late 23rd century. As a result, the House of Kor was dissolved upon Kor's death. (DS9 episodes: "Blood Oath", "Once More Unto the Breach")