<s>[INST] <<SYS>> This is a medical question of type : causes <</SYS>> What causes Norum disease ? [/INST] What causes Norum disease? Norum disease is caused by defects in the LCAT gene. The clinical manifestations of LCAT deficiency are probably due to a defect in LCAT-mediated cholesterol ester formation and, therefore, accumulation of unesterified cholesterol in certain tissues, such as the cornea, kidneys, and erythrocytes (red blood cells). </s>