Brain and Nerves

Unlike some other MPS disorders, such as MPS I Hurler syndrome, cognitive development is typically normal in MPS VI. Impaired hearing or vision may, however, contribute to poor school performance, in some cases creating the superficial appearance of cognitive deficit.¹

One central nervous system complication which does occur frequently is communicating hydrocephalus. It may present in a number of ways, including drowsiness, headache, and behavioral changes. Untreated hydrocephalus can accelerate the occurrence of blindness.²

Cervical spinal cord compression caused by meningeal thickening and a stenotic spinal canal has been described in MPS VI. This may cause myelopathy and subsequent paralysis. Peripheral nerve entrapment, including carpal tunnel syndrome, is common in MPS VI but usually has an atypical presentation and therefore is under-diagnosed. MPS VI patients experiencing carpal tunnel syndrome usually lack some typical symptoms, such as pain, tingling, or loss of feeling in the fingertips, and instead present with atrophy of the thenar muscle, difficulty with fine motor tasks, and weakness of hand grasp.¹

1. Neufeld EF, Muenzer J. The mucopolysaccharidoses. In: Scriver CR, Beaudet AL, Sly WS, Valle D, eds. The Metabolic and Molecular Bases of Inherited Disease. Vol 3. 8th ed. New York, NY: McGraw- Hill; 2001:3421-3452.
2. Vougioukas VI, Berlis A, Kopp MV, et al. Neurosurgical interventions in children with Maroteaux-Lamy syndrome. Case report and review of the literature. Pediatr Neurosurg. 2001;35:35-38. Review.