Independent Studies of Dextromethorphan and of Donepezil Hydrochloride for Rett Syndrome
Rett syndrome (RTT) is a disorder in which the nervous system does not develop properly. RTT generally affects girls, but there are some boys who have been diagnosed with RTT. Symptoms of RTT include small brain size, poor language skills, repetitive hand movements, and seizures. This study will evaluate the effectiveness of two drugs in treating the symptoms of RTT.
RTT is a neurodevelopmental disorder characterized by apparently normal early development followed by loss of purposeful hand use, distinctive hand stereotypies, slowed brain growth, loss of language, respiratory irregularities, GI disturbances, gait abnormalities, seizures, and mental retardation. These symptoms appear between ages 6 and 18 months (stage 2 of the disease) following apparently normal development (stage 1). Subsequently, there is gradual stabilization of severe mental retardation and motor compromise (stage 3). The majority (70% to 80%) of patients demonstrate mutations in the methyl-CpG-binding-protein-2 (MeCP2) gene, a transcription repressor located on chromosome Xq28. The disorder predominantly affects females, but a few males with mutations in MeCP2 have been identified, even though many of them do not have the classic symptoms recognized in females.
Recent studies demonstrate increased brain N-methyl-D-aspartate (NMDA) receptors in stages 2 and 3 of the disease. This age-specific increase in glutamate levels and their receptors contribute to brain damage. This first study will examine the effectiveness of dextromethorphan, an NMDA receptor antagonist, to ameliorate symptoms. Participants will be randomized to receive one of three doses of dextromethorphan. All participants will be admitted to the hospital for three days at the beginning of the study. During the hospitalization, participants will undergo physical exam, Dexascan, MRI, EEG, behavioral assessment, laboratory testing, and neuropsychological evaluations. Six months after baseline assessment, participants will be rehospitalized for 3 days for similar assessments.
Reduction in choline acetyltransferase activity in RTT patients may also contribute to disturbed cortical development and psychomotor retardation in RTT. Therefore, the second part of the study will evaluate the effect of donepezil hydrochloride, an inhibitor of acetylcholine-esterase, on acetylcholine levels. This portion of the study will not begin until pharmacokinetic data for donepezil in children is available.
Allocation: Randomized, Control: Dose Comparison, Endpoint Classification: Efficacy Study, Intervention Model: Factorial Assignment, Masking: Open Label, Primary Purpose: Treatment
dextromethorphan, donepezil hydrochloride
Kennedy Krieger Institute
Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
Results (where available)
- Source: http://clinicaltrials.gov/show/NCT00069550
- Information obtained from ClinicalTrials.gov on July 15, 2010
Medical and Biotech [MESH] Definitions
Methyl-cpg-binding Protein 2
A DNA-binding protein that interacts with methylated CPG ISLANDS. It plays a role in repressing GENETIC TRANSCRIPTION and is frequently mutated in RETT SYNDROME.
An inherited neurological developmental disorder that is associated with X-LINKED INHERITANCE and may be lethal in utero to hemizygous males. The affected female is normal until the age of 6-25 months when progressive loss of voluntary control of hand movements and communication skills; ATAXIA; SEIZURES; autistic behavior; intermittent HYPERVENTILATION; and HYPERAMMONEMIA appear. (From Menkes, Textbook of Child Neurology, 5th ed, p199)
Dextro form of levorphanol. It acts as a noncompetitive NMDA receptor antagonist, among other effects, and has been proposed as a neuroprotective agent. It is also a metabolite of DEXTROMETHORPHAN.
4(1-Naphthylvinyl)pyridine hydrochloride. Cholinesterase inhibitor. Synonym: YuB 25.
Used in the form of the hydrochloride as a reagent in ANALYTICAL CHEMISTRY TECHNIQUES.
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