Signs of the severe form are joint stiffness, mental deterioration, dwarfing, and progressive deafness. Death usually occurs by age 15. Symptoms of the mild form include short stature, limitation of motion, and features such as an enlarged forehead, lips, and tongue and misaligned teeth. Life span may be normal. Individuals with MPS III, or Sanfilippo syndrome, experience progressive dementia and mental deterioration in childhood.
Death usually occurs in the late teens.
Symptoms of MPS IV, or Morquio syndrome, usually appear in infancy and may include severe dwarfing and corneal clouding. Intelligence is normal. Cardiac or respiratory disease may cause death in the third or fourth decade of life. MPS VI, or Maroteauz-Lamy syndrome, resembles Hurler syndrome. Onset is in infancy, however, intelligence is normal.