A-067 Behavior and Blood Biomarker Differences for Children with Fragile X Syndrome and Idiopathic Autism

Abstract

Abstract Objective A clearer understanding of behavioral and blood biomarker differences in individuals with Fragile X Syndrome (FXS) and idiopathic autism is necessary as advancement in gene therapies and medication targeted to the FXS single gene abnormality are being trialed in autism. Our primary objective is to determine Autism Diagnostic Interview-Revised (ADIR) item/domain differences in children with FXS and autism, controlling for age, IQ, and autism severity. Our secondary objective is to demonstrate blood protein biomarker group differences. Method Participants were drawn from a larger study examining amyloid precursor protein (APP) metabolite levels in children with FXS (n = 18) and autism (n = 21) from Indiana University Riley Hospital Clinics. Complete data were available for children with full FXS mutations (n = 9, and autism (n = 9, one girl), matched for age, MSEL IQ, and CARS severity scores. ADI-R was administered to mothers by staff trained to research reliability. Western blot for APP and fragile X mental retardation protein (FMRP) were performed on peripheral blood mononuclear cells. Results No significant group differences are seen via Mann–Whitney U after Bonferroni multiple comparison, likely due to low power. However, two trends in our data corroborate recent reports: social smiling (item 51) is more intact for FXS [U(18) = 20.5,Z = -1.76,p = 0.085, 95%CI = -0.15–1.93,r = 0.41] and Restricted Behavior Scale [U(18) = 21,Z = -1.72,p = 0.09,95%CI = -0.57–2.79,r = 0.40] was more pronounced in autism. Western blot showed variations in APP and FMRP between FXS, autism and controls (Figure 1). Conclusions Trends in behavioral ADI-R scores and blood biomarker APP differences exist between FXS and idiopathic autism. Further study of these preliminary results should inform appropriate treatment endpoints for autism and FXS.