Antioxidant Therapy With N-acetylcysteine for Learning and Motor Behavior in Children With Neurofibromatosis Type 1

Children with neurofibromatosis type 1 (NF1) commonly suffer from the effects of cognitive, behavioral, and motor impairments. At present there is no specific treatment for this NF1 complication. However, data from rodent models of NF1 along with uncontrolled clinical observations in children with NF1 suggest that the anti-oxidant, glutamate modulating compound N-Acetyl Cysteine (NAC) may reduce these impairments. Of particular interest is a murine study analyzing the central nervous system manifestations of NF1 at our institution. That study revealed a role for myelin-forming oligodendrocytes in the control of nitric oxide synthases (NOS) and their product, nitric oxide, in maintenance of brain structure and function, including regulation of behavior and motor control. Treating these mice with NAC corrected cellular and behavioral abnormalities. N-Acetyl Cysteine is available over the counter and has been used by thousands of individuals; moreover, it has shown some promise in clinical trials for psychiatric disorders. In order to better understand treatment mechanisms, and possibly predict long-term outcomes, the investigators propose concurrently to explore Specific Aim 1 (1.1, 1.2, and 1.3) exploratory potential disease biomarkers as outlined below. The primary outcome of this study is motor function rated with the Physical and Neurological Examination for Subtle Signs (PANESS), a validated scale that consistently demonstrates significant impairments in children with Attention Deficit Hyperactivity Disorder (ADHD), and which our preliminary data suggest may demonstrate more extreme problems in children with NF1. The first exploratory biomarker is motor system inhibitory physiology, measured using Transcranial Magnetic Stimulation (TMS). Preliminary measures in our NF1 population also show abnormalities similar to established findings in ADHD. The second exploratory biomarker is metabolomics profiling for the biomarker of oligodendrocyte dysfunction in NF1 participants: autotaxin. Preliminary data in our NF1 population showed specific signal abnormalities in the NF1 population compared to healthy controls. Therefore, the investigators propose to perform a double-blind placebo controlled, prospective, Phase IIa study to explore safety, tolerability, and efficacy of NAC on learning and motor behavior in children with NF1 aged 8 through 16 years old.

Sex

All

Minimum age

8 Years

Maximum age

16 Years

Inclusion Criteria:

1. Males and females aged 8 - 16 years at time of enrollment whom meet NIH diagnostic criteria for NF1.
2. Participants must have a full-scale intelligence quotient (IQ) of 70 or above, as determined by neurocognitive testing within the last 3 years or during the enrollment process.
3. Participants on stimulant or any other psychotropic medication should stay on a stable dose for at least 30 days before entering the study.

Exclusion Criteria:

1. Participants should not be receiving chemotherapy currently, or have received chemotherapy in the 6 months prior to entering the study.
2. No active intracranial lesions (stable low grade glioma are acceptable) or epilepsy diagnosis.
3. Major Depression, Bipolar Disorder, Conduct Disorder, Adjustment Disorder, other major Anxiety Disorders, or other developmental psychiatric diagnoses, based on the child's history or on parent and child responses from the Kiddie Schedule for Affective Disorders and Schizophrenia (KSADS). Note that while this is an exclusion for participation in the study if there is a prior evaluation available, this becomes a criterion, after inclusion, for the investigator to withdraw the child from the study prior to completion if identified on the first study day.
4. For females, pregnancy.
5. Current use of antidepressants, non-stimulant ADHD medications, dopamine blocking agents, mood stabilizers.
6. Implanted brain stimulator, vagal nerve stimulator, ventriculoperitoneal (VP) shunt, cardiac pacemaker, or implanted medication port.
7. Asthma (bronchospasm has been reported as occurring infrequently and unpredictable when acetylcysteine is used as a mucolytica agent).
8. High risk of upper gastrointestinal (GI) hemorrhage. Examples: presence of esophageal varices or peptic ulcers

• BACKGROUNDAcosta MT, Gioia GA, Silva AJ. Neurofibromatosis type 1: new insights into neurocognitive issues. Curr Neurol Neurosci Rep. 2006 Mar;6(2):136-43. doi: 10.1007/s11910-996-0036-5. PMID 16522267
• BACKGROUNDBallester R, Marchuk D, Boguski M, Saulino A, Letcher R, Wigler M, Collins F. The NF1 locus encodes a protein functionally related to mammalian GAP and yeast IRA proteins. Cell. 1990 Nov 16;63(4):851-9. doi: 10.1016/0092-8674(90)90151-4. PMID 2121371
• BACKGROUNDRosser TL, Packer RJ. Neurocognitive dysfunction in children with neurofibromatosis type 1. Curr Neurol Neurosci Rep. 2003 Mar;3(2):129-36. doi: 10.1007/s11910-003-0064-3. PMID 12583841
• BACKGROUNDCasnar CL, Janke KM, van der Fluit F, Brei NG, Klein-Tasman BP. Relations between fine motor skill and parental report of attention in young children with neurofibromatosis type 1. J Clin Exp Neuropsychol. 2014;36(9):930-43. doi: 10.1080/13803395.2014.957166. Epub 2014 Oct 6. PMID 25284746
• BACKGROUNDWalsh KS, Janusz J, Wolters PL, Martin S, Klein-Tasman BP, Toledo-Tamula MA, Thompson HL, Payne JM, Hardy KK, de Blank P, Semerjian C, Gray LS, Solomon SE, Ullrich N; REiNS International Collaboration. Neurocognitive outcomes in neurofibromatosis clinical trials: Recommendations for the domain of attention. Neurology. 2016 Aug 16;87(7 Suppl 1):S21-30. doi: 10.1212/WNL.0000000000002928. PMID 27527646
• BACKGROUNDAcosta MT, Bearden CE, Castellanos FX, Cutting L, Elgersma Y, Gioia G, Gutmann DH, Lee YS, Legius E, Muenke M, North K, Parada LF, Ratner N, Hunter-Schaedle K, Silva AJ. The Learning Disabilities Network (LeaDNet): using neurofibromatosis type 1 (NF1) as a paradigm for translational research. Am J Med Genet A. 2012 Sep;158A(9):2225-32. doi: 10.1002/ajmg.a.35535. Epub 2012 Jul 20. PMID 22821737
• BACKGROUNDPride N, Payne JM, Webster R, Shores EA, Rae C, North KN. Corpus callosum morphology and its relationship to cognitive function in neurofibromatosis type 1. J Child Neurol. 2010 Jul;25(7):834-41. doi: 10.1177/0883073809350723. Epub 2010 Feb 8.