Development Delay

Assessment of neurodevelopment and cognitive ability is essential at the time of diagnosis with MPS I/MPS II and at regular intervals thereafter.1,2

The primary purpose of neurodevelopmental testing in MPS I/MPS II is to determine the cognitive and educational abilities of an affected child. This information can be used to assist parents and caregivers in helping the child learn as much as they can before development plateaus and regresses, by focusing on their functional age. Because skills developed early may be retained as the disease progresses, it is important that affected children receive as much developmental stimulation as possible early in the disease course.1,3

Neurodevelopmental assessment of children with MPS I/MPS II has significant limitations and requires a multidisciplinary approach. This is because children with MPS I/MPS II may have other physical and neurological manifestations that are not taken into account by standard assessment tools and which can interfere with their performance. For example, hearing loss, vision impairment and enlarged tongue are common signs and symptoms of MPS I/MPS II that may limit the ability to understand and perform requested tasks. Therefore, neurodevelopmental assessments should be interpreted in the context of the disease process and the results from other tests such as hearing, vision, and oral motor skills.3


  1. 1.Muenzer J, Wraith JE, Clarke LA, International Consensus Panel on M, Treatment of Mucopolysaccharidosis I. (2009) Mucopolysaccharidosis I: management and treatment guidelines. Pediatrics 123(1): 19-29.
  2. 2.Scarpa M, Almassy Z, Beck M, et al. (2011) Mucopolysaccharidosis type II: European recommendations for the diagnosis and multidisciplinary management of a rare disease. Orphanet J Rare Dis 6: 72.
  1. 3.Martin HR, Poe MD, Reinhartsen D, et al. (2008) Methods for assessing neurodevelopment in lysosomal storage diseases and related disorders: a multidisciplinary perspective. Acta Paediatr 97(457): 69-75.