Kcnq1, also known as Kv7.1, is a voltage-dependent K+ channel. It is crucial in regulating gastric acid secretion, salt and glucose homeostasis, and heart rhythm. It functions in various pathways and its activity is tissue-specifically regulated by co-assembly with beta subunits KCNE1-5 [1].

Kcnq1 mutations are strongly associated with long QT syndrome (LQTS). Heterozygous mutations in Kcnq1 cause Romano-Ward syndrome (LQT1 only), while homozygous mutations lead to JLNS (LQT1 and deafness). The mutant Kcnq1 alpha-subunits combine with normal ones to form abnormal IKS channels, mainly acting through a dominant-negative or loss-of-function mechanism [3]. Additionally, the G allele of Kcnq1 variant rs163184 is associated with a lower glycosylated hemoglobin reduction after exenatide treatment in type 2 diabetes mellitus patients, indicating its role in glycemic response regulation [2].

In conclusion, Kcnq1 is essential for multiple physiological functions, especially in maintaining normal heart rhythm and glucose metabolism. Studies on Kcnq1 mutations in relation to LQTS and its role in glycemic response provide insights into these disease areas. Understanding Kcnq1's functions through genetic models helps in uncovering the underlying mechanisms of these diseases and may lead to the development of targeted therapies.