Jocelyn J LeBlanc1,2,3, Geneva DeGregorio1, Eleonora Centofante2, Vanessa K Vogel-Farley1, Katherine Barnes4, Walter E Kaufmann3,4, Michela Fagiolini2,3, Charles A Nelson1,3,5. 1. Laboratories of Cognitive Neuroscience, Division of Developmental Medicine, Boston Children's Hospital, Boston. 2. F. M. Kirby Neurobiology Center, Department of Neurology, Boston Children's Hospital, Boston. 3. Harvard Medical School, Boston. 4. Rett Syndrome Program, Department of Neurology, Boston Children's Hospital, Boston. 5. Harvard Graduate School of Education, Cambridge, MA.
Abstract
OBJECTIVE: Rett syndrome (RTT) is a neurodevelopmental disorder caused by mutation of the X-linked MECP2 gene and characterized by developmental regression during the first few years of life. The objective of this study was to investigate if the visual evoked potential (VEP) could be used as an unbiased, quantitative biomarker to monitor brain function in RTT. METHODS: We recorded pattern-reversal VEPs in Mecp2 heterozygous female mice and 34 girls with RTT. The amplitudes and latencies of VEP waveform components were quantified, and were related to disease stage, clinical severity, and MECP2 mutation type in patients. Visual acuity was also assessed in both mice and patients by modulating the spatial frequency of the stimuli. RESULTS: Mecp2 heterozygous female mice and RTT patients exhibited a similar decrease in VEP amplitude that was most striking in the later stages of the disorder. RTT patients also displayed a slower recovery from the principal peak of the VEP response that was impacted by MECP2 mutation type. When the spatial frequency of the stimulus was increased, both patients and mice displayed a deficit in discriminating smaller patterns, indicating lower visual spatial acuity in RTT. INTERPRETATION: VEP is a method that can be used to assess brain function across species and in children with severe disabilities like RTT. Our findings support the introduction of standardized VEP analysis in clinical and research settings to probe the neurobiological mechanism underlying functional impairment and to longitudinally monitor progression of the disorder and response to treatment.
OBJECTIVE:Rett syndrome (RTT) is a neurodevelopmental disorder caused by mutation of the X-linked MECP2 gene and characterized by developmental regression during the first few years of life. The objective of this study was to investigate if the visual evoked potential (VEP) could be used as an unbiased, quantitative biomarker to monitor brain function in RTT. METHODS: We recorded pattern-reversal VEPs in Mecp2 heterozygous female mice and 34 girls with RTT. The amplitudes and latencies of VEP waveform components were quantified, and were related to disease stage, clinical severity, and MECP2 mutation type in patients. Visual acuity was also assessed in both mice and patients by modulating the spatial frequency of the stimuli. RESULTS:Mecp2 heterozygous female mice and RTT patients exhibited a similar decrease in VEP amplitude that was most striking in the later stages of the disorder. RTT patients also displayed a slower recovery from the principal peak of the VEP response that was impacted by MECP2 mutation type. When the spatial frequency of the stimulus was increased, both patients and mice displayed a deficit in discriminating smaller patterns, indicating lower visual spatial acuity in RTT. INTERPRETATION: VEP is a method that can be used to assess brain function across species and in children with severe disabilities like RTT. Our findings support the introduction of standardized VEP analysis in clinical and research settings to probe the neurobiological mechanism underlying functional impairment and to longitudinally monitor progression of the disorder and response to treatment.
Authors: Abhishek Banerjee; Rajeev V Rikhye; Vincent Breton-Provencher; Xin Tang; Chenchen Li; Keji Li; Caroline A Runyan; Zhanyan Fu; Rudolf Jaenisch; Mriganka Sur Journal: Proc Natl Acad Sci U S A Date: 2016-11-01 Impact factor: 11.205
Authors: Lieselot L G Carrette; Roy Blum; Weiyuan Ma; Raymond J Kelleher; Jeannie T Lee Journal: Proc Natl Acad Sci U S A Date: 2018-07-23 Impact factor: 11.205