Objectives To assess autism spectrum disorder (ASD) behaviors in children with mucopolysaccharidosis type IIIA (MPS IIIA) using a standard measure, understand the behavioral evolution of the disease, and provide specific guidelines for diagnosis. Study design Children (n = 21) with documented enzyme deficiency and SGSH gene mutations, cognitive age-equivalent >12 months, and early onset were administered the Autism Diagnostic Observation Schedule (ADOS) (module 1) and Bayley Scales of Infant Development-Third Edition. ADOS Social Affect and Restricted Repetitive Behavior total scores, as well as Bayley Scales of Infant Development-Third Edition cognitive age-equivalent scores, are reported using descriptive statistics and graphic presentations. Results Thirteen of the 21 children evaluated met the ADOS criteria for ASD/autism. ADOS score was strongly associated with age; all 11 children aged >46 months met the criteria, compared with only 2 of 10 aged <46 months. Social and affective abnormalities were most frequent; restricted interests and repetitive behaviors were largely absent. Lack of cognitive growth paralleled ADOS score. Conclusion An increased incidence of ASD-like social behaviors was seen at age 3-4 years in children with early-onset MPS IIIA. Although more frequent in the severely impaired children, ASD-like behaviors were observed across the entire range of cognitive impairment. Clinicians must be aware that when a child acquires ASD-like behaviors, MPS IIIA should be included in the differential diagnosis.
Bibliographical noteFunding Information:
We would like to acknowledge the University of Minnesota Autism Spectrum and Neurodevelopmental Disorders Clinic; the Center for Neurobehavioral Development; Amy Esler, PhD (University of Minnesota Autism Spectrum and Neurodevelopmental Disorders Clinic), who conducted several of the ADOS assessments; Brianna Yund (funded by National Institute of Neurological Disorders and Stroke [ U54NS065768 ]), who entered the data; and the families who helped advance research by participating in this study. We thank Patrick Haslett, MD (employee of Shire Pharmaceuticals) for his role in designing the overall trial and assistance in reviewing the initial manuscript.
- Autism Diagnostic Observation Schedule
- Autism spectrum disorder
- MPS IIIA
- Mucopolysaccharidosis type IIIA