ABSTRACT
The Sanfilippo Behavior Rating Scale (SBRS), a 68 item questionnaire, has been developed to assess the behavioral phenotype of children with Sanfilippo syndrome and its progression over time. Fifteen scales rate orality, movement/activity, attention/self-control, emotional function including anger and fear, and social interaction. Items within scales intercorrelate; measures of internal consistency are adequate. Twelve scales are grouped into 4 abnormality clusters: Movement, Lack of fear, Social/emotional and Executive Dysfunction. A Loess age-trajectory analysis showed that Lack of Fear, Social/Emotional and Executive Dysfunction increased steadily with age; Orality and Mood/Anger/Aggression leveled off. Movement peaked around 6years, then declined as children's excessive/purposeless actions stopped. Compared with standard scales, SBRS Movement was appropriately associated with the Vineland Motor scale; SBRS Lack of Fear had significant associations with the Autism Diagnostic Observation Schedule (ADOS), indicating a symptom overlap between Sanfilippo syndrome and autism. This suggests that reduced fearfulness may be the most salient/sensitive SBRS marker of disease progression. Volumetric MRI showed that increased Lack of Fear was significantly associated with reduced amygdala volume, consistent with our hypothesis that the behavior seen in Sanfilippo syndrome is a variant of Klüver-Bucy syndrome. Hippocampal volume loss had twice the effect on Social-Emotional Dysfunction as amygdala loss, consistent with a hippocampal role in attachment and social emotions. In conclusion, the SBRS assesses the Sanfilippo behavioral phenotype; it can measure behavior change that accompanies disease progression and/or results from treatment.
Subject(s)
Behavior Rating Scale , Behavior , Mucopolysaccharidosis III/psychology , Adolescent , Amygdala/pathology , Autistic Disorder/diagnosis , Autistic Disorder/psychology , Child , Child, Preschool , Fear , Female , Humans , Infant , Male , Mucopolysaccharidosis III/diagnosis , Mucopolysaccharidosis III/pathology , Neuroimaging , Phenotype , Social Behavior , Surveys and QuestionnairesABSTRACT
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.
