<s>[INST] <<SYS>> This is a medical question of type : causes <</SYS>> What causes Simple Kidney Cysts ? [/INST] The cause of simple kidney cysts is not fully understood. Obstruction of tubulestiny structures within the kidneys that collect urineor deficiency of blood supply to the kidneys may play a role. Diverticulasacs that form on the tubulesmay detach and become simple kidney cysts. The role of genetic factors in the development of simple kidney cysts has not been studied. </s>