In wireless IoT networks, when each node communicates with maximum power, power consumption increases unnecessary. Therefore, the transmission power of each node is adjusted using topology control. Because topology control decreases the number of edges between nodes, the fault tolerance may decline. One solution is to employ fault tolerant topology control using k-connectivity. Existing fault-tolerant topology control assumes that a network is constructed for one domain and the environment has a fixed k value. With a fixed k value, extra links are prepared, and power consumption increases. On the other hand, since various communications are shared in an IoT environment, the connectivity requirements change. Consequently, setting the k value for each pair of nodes according to the importance of data can eliminate extra links and reduce power consumption. Herein a method is proposed to realize topology control using a variable k value. To obtain a solution by the genetic algorithm, we propose an encoding scheme and define a fitness function. Simulation experiments demonstrate that the proposed method can construct a more power-efficient topology than the existing topology control method.