Mucopolysaccharidosis III (MPSIII) syndrome is characterized by a severe cognitive decline ending in dementia and death. MPSIII is also associated with a range of abnormal and disruptive behaviors that can include, but go well beyond, childhood noncompliance and oppositionality. The purpose of this study is to conduct a cross-sectional investigation to identify the behavioral phenotype and its neural basis in MPSIII. An overall goal of this research is to develop easily administered, sensitive and specific neurobehavioral markers to characterize the behavioral phenotype(s) of MPSIII, track their progression, and to delineate their possible neural substrates. The study looks to develop develop a sensitive and specific behavioral rating of disease progression in MPS III which can be used for clinical outcome studies. The research objectives are: <ul> <li>Develop a measure for the use of health professionals to use in tracking MPSIII phenotypes and disease progression.</li> <li>Test our model of MPSIII with objectively recorded behaviors in a well-defined experimental setting.</li> <li>Elucidate the neural bases of MPSIII by correlating behavioral profiles with changes in brain structures through quantitative neuroimaging.</li> <li>Determine the relationship between the loss of cognitive functions and development of behavioral abnormalities in MPSIII.</li> </ul> This is an observational pilot study that will enroll 45 individuals with MPS III Type A or B. Those participating in the study will be evaluated during a one-day assessment and chart review.

Characterizing Phenotype(s) in MPS III

Acquired autistic behaviors in children with mucopolysaccharidosis type IIIA.

Mucopolysaccharidosis Type IIIA presents as a variant of Klüver–Bucy syndrome