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Legends. Cerebral3-[18F]fluoro-5-(2-pyridinylethynyl)benzonitrile([18F]FPEB)uptake and fragileX messenger ribonucleoprotein in men with fragile X syndrome Table S1. Concomitant medications of participants from the Institute for Neurodegenerative Disorders (IND) Table S2. Demographic and clinical characteristics of participants from the Institute for Neurodegenerative Disorders (IND) Table S3. Demographic and clinical characteristics of participants from the Johns Hopkins University (JHU) Table S4. Genetic and psychological assessments of participants from the Institute for Neurodegenerative Disorders (IND) Table S5. Genetic and psychological assessments of participants from the Johns Hopkins University (JHU) Table S6. Fragile X Mental Retardation Protein (FMRP) in nanogram per microgram total protein for ten healthy people with typical development (TD) with normal CGG repeat sizes [range (20, 37)] utilizing the same analyses as the other participants Table S7. Positron emission tomography (PET) data and analyses for participants from the Institute for Neurodegenerative Disorders (IND) Table S8. Positron emission tomography (PET) data and analysis of participants from the Johns Hopkins University (JHU) Table S9. Correlation coefficients between Fragile X Mental Retardation Protein (FMRP) (Table S4) and [18F]FPEB uptake (Wong DF et al. 2013) for participants with fragile X syndrome (Table S7) Table S10. Correlation coefficients between Fragile X Mental Retardation Protein (FMRP) (Table S4) and [18F]FPEB uptake (Wong DF et al. 2013) for participants with fragile X syndrome and fragile X syndrome-mosaicism (Table S7) Poster. Cerebral3-[18F]fluoro-5-(2-pyridinylethynyl)benzonitrile([18F]FPEB)uptake and fragileX messenger ribonucleoprotein in men with fragile X syndrome Video. Cerebral3-[18F]fluoro-5-(2-pyridinylethynyl)benzonitrile([18F]FPEB)uptake and fragileX messenger ribonucleoprotein in men with fragile X syndrome The authors thank Flora Tassone, Ph.D., Department of Biochemistry and Molecular Medicine, School of Medicine, UC Davis Health, Sacramento, California, for providing genetic and protein data about participants.

This research was made possible by a Radiology BRidge/Development Funding Initiative to STimulate and Advance Research (RAD BriteStar Bridge) Award from the Johns Hopkins University School of Medicine, Baltimore, Maryland, to JRB; and the Intellectual and Developmental Disabilities Research Center (U54 HD079123), Kennedy Krieger Institute, Johns Hopkins Medical Institutions. Baltimore, Maryland, to JRB.