This is a heritable disorder of fat metabolism that can cause symptoms at birth, such as persistent jaundice and diarrhea.  Cataracts may be present in the first decade of life and often need to be removed by the third decade.  In fact, cataracts are the first sign in 75% of patients.  Later, in the second and third decades, unsightly cholesterol deposits appear in tendons which connect muscle to bone.  Perhaps even more serious are the progressive neurologic signs such as unsteadiness and mental changes including dementia.  These generally appear in early adulthood, after the onset of cataracts and tendon deposits but earlier signs, even in children, can be found if careful examination is done.  Many individuals have evidence of atherosclerosis.