A Phase 1 interventional study of [18F]flumazenil in Fragile X Syndrome (FXS) and Idiopathic Intellectual Developmental Disorder (IDD), sponsored by Stanford University. Terminated at 1 site in United States. Open to male participants aged 18 Years to 30 Years. Per ClinicalTrials.gov, last updated 2021-01-28.
Sponsored by Stanford University · Phase 1, Interventional, and Basic science
The investigators wish to compare the brain distribution of GABA(A) receptors and GABA levels in young adult males with Fragile X Syndrome compared to idiopathic intellectual developmental disorder. The radiopharmaceutical [18F]flumazenil has been used to study GABA(A) receptor distribution in other genetic syndromes with autistic features; however, despite overwhelming evidence supporting the importance of the GABAergic system in FXS, no clinical investigation of this system in human FXS has been reported in the literature. Therefore, this study will provide the first in vivo comprehensive examination of the GABAergic system in FXS using hybrid positron emission tomography/ magnetic resonance imaging (PET/MRI).
Fragile X syndrome (FXS) is the most common genetic cause of autism spectrum disorder (ASD). Converging evidence suggests that GABAergic dysfunction occurs in FXS. The investigators wish to examine brain distribution of GABA (A) receptors in young adult males with FXS using hybrid PET/MRI with [18F]flumazenil. This project will study the distribution of GABA(A) receptors in 15 young male adults with FXS (18-30 years old) compared to 15 age-matched male subjects with idiopathic intellectual developmental disorder (IDD) as controls. Simultaneous PET/MRI acquisition is an optimal technique to study in vivo GABAergic dysfunction and GABAa receptor distribution.
110 studies on the registry are indexed under Fragile X Syndrome; 23 are open to participants now.
This study's enrollment of 17 is below the median of 58 across 88 interventional studies indexed under Fragile X Syndrome.
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Of its 259 completed or terminated interventional studies of FDA-regulated products, 197 (76%) have results posted.
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Inclusion Criteria for participants with FXS:
Exclusion criteria for participants with FXS:
Inclusion criteria for participants with IDD:
Exclusion Criteria for participants with IDD:
Adult males aged 18-30 years diagnosed with FXS will undergo a non-invasive F18 FMZ PET/MRI scan to determine GABA(A) receptor density; developmental dynamics of GABA(A) receptor distribution, and structural neuroanatomy and connectional anatomy.
Drug: [18F]flumazenil
Adult males aged 18-30 years diagnosed with idiopathic intellectual developmental disorder will undergo a non-invasive F18 FMZ PET/MRI scan to determine GABA(A) receptor density; developmental dynamics of GABA(A) receptor distribution, and structural neuroanatomy and connectional anatomy.
Drug: [18F]flumazenil
\[18F\]flumazenil is a PET radiopharmaceutical that can be used to determine gamma-aminobutyric acid (GABA(A)) receptor density.
Also known as: F18 FMZ
Non-displaceable binding potential of [18F]flumazenil (F18 FMZ)
Binding potential provides an estimate of the GABA (A) receptor distribution and affinity of \[18F\]flumazenil-PET to the GABA receptors. Binding potential will be measured in patients with fragile X syndrome and control group comprising individuals with idiopathic intellectual developmental disorder. Using imaging data obtained from PET that was corrected for attenuation and partial volume effects by MRI, nuclear medicine physicians will draw regions of interest (ROI's) around the areas of the brain listed below to estimate the F18 FMZ non-displaceable binding potential (BPnd) of F18 FMZ to GABA (A) receptors in FXS.
Time frame: Up to 2 hours per scan on a single study day
GABA (A) receptor density in fragile X syndrome (FXS) patients relative to control group comprising individuals with idiopathic Intellectual Developmental Disorder (IDD)
Binding potential measurements will be compared between participants with fragile X syndrome and control group with idiopathic intellectual developmental disorder(IDD) using the PET radiotracer \[18F\]flumazenil-PET. Binding Potential (BPnd) is estimated as the distribution volume ratio (DVR) -1. DVR's of tracers are used in PET receptor studies where the radiopharmaceutical can be specifically bound to receptors; nonspecifically bound to other macromolecular components, or free in tissue (FT). DVR is calculated using a Logan Plot, which uses the dynamic PET images obtained during imaging and compartment modeling to graphically analyze by linear regression pharmacokinetic data for radiopharmaceuticals that undergo 'reversible' uptake. PET scans of FXS patients will be compared to the PET scans of control group.
Time frame: Up to 2 hours per scan on a single study day
Plan to share: No
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