To date, it was known that AQP3 constitutes an important molecule in the onset of diabetes; transgenic Aqp3-deficient mice develop nephrogenic diabetes insipidus [14]; changes in the expression of AQP3 in the adipose tissue [15], liver [16], or kidneys [17] have been associated with the development of type 2 diabetes. The gene discussed is AQP3; the disease is type 2 diabetes mellitus.