Cognitive and behaviour profiles of children with mucopolysaccharidosis Type II.

Mucopolysaccharidosis Type II (MPS II) or Hunter Syndrome is a rare X-linked condition, due to a defect in a lysosomal enzyme involved in the breakdown of glycosaminoglycans. It is a progressive condition with worsening over time; however, symptom severity and progression rates vary. Normal intellectual function has been reported in males with mild MPS II but few studies are available that provide comprehensive cognitive profiles. Enzyme replacement therapy (ERT) can stabilize physical symptoms and has become standard treatment. Whether ERT can influence cognition is currently unknown. Considering this, we conducted cognitive, fine motor, and behavioural assessments with three males (7;6-12;1 years) with mild MPS II before and after ERT. Generally, cognition, fine motor skills, and behaviour were in the normal range; however, specific deficits in attention and executive function were identified. Following ERT, some memory improvements were seen. Executive deficits remained, and processing speed declined over time.