<s>[INST] <<SYS>> This is a medical question of type : information <</SYS>> What is (are) essential pentosuria ? [/INST] Essential pentosuria is a condition characterized by high levels of a sugar called L-xylulose in urine. The condition is so named because L-xylulose is a type of sugar called a pentose. Despite the excess sugar, affected individuals have no associated health problems. </s>