Natural History of MPS Disorders – What Do We Know About Cognition Over Time?
Elsa Shapiro, PhD, A.B.P.P., LP
Dr. Elsa Shapiro delivers an overview of the effects of MPS on neurocognitive functions, how they differ in each syndrome type, and the effectiveness of transplant and enzyme replacement therapy for each. In most of the MPS disorders, brain abnormality is associated with a broad spectrum of cognitive and behavioral effects. In severe MPS I (Hurler Syndrome), a neuronopathic progressive syndrome, early treatment both in Hematopoietic Stem Cell Transplant (HSCT) and Enzyme Replacement Therapy (ERT), have produced the best outcomes. In MPS II, predicting the cognitive developmental course has been more difficult, with cognitive decline typically beginning from age 2 to 5.
A faster decline is seen in MPS III (Sanfilippo Syndrome), for which neurologic and cognitive problems are the primary symptoms. After a normal first year of development, cognitive decline typically begins in year 2. Clinical trials for MPS III have failed to have a positive impact on cognition. MPS IVA and VI are not known to have progressive cognitive impairment, though studies have shown possible difficulties with executive functions (attention, visual processing efficiency) in MPS VI. Cognitive impairment in MPS VII can be similar to MPS I, but with fewer than 200 diagnosed patients, timing of progression is still unknown.
Neurobehavioral manifestations and other considerations in MPS
Julie Eisengart, PhD, LP
Dr. Julie Eisengart explores the likelihood that all MPS types have some underappreciated neurobehavioral symptoms, many of which could be the indirect effect of somatic symptoms. Less obvious behavioral symptoms such as anxiety, inattention, or slow processing, can often be overshadowed by hyperactivity, physicality, and other more observable symptoms. These behavioral symptoms can negatively impact other aspects of a child’s life, including social isolation, sleep problems, and a reduction in educational and community access.
Management techniques for behavioral symptoms should always be individualized. MPS is not a cookie cutter disease. Severe behaviors are challenging for caregivers, who are often more concerned about emotional and behavioral symptoms than cognitive ones. Because caregiver and family burden is so high, the impact of physical, social-emotional, financial, and other stressors should be considered and measured in clinical trials.
