Clinical Trial: Neurologic Injuries in Adults With Urea Cycle Disorders

Study Status: Completed
Recruit Status: Completed
Study Type: Observational

Official Title: Assessing Neural Mechanisms of Injury in Inborn Errors of Urea Metabolism Using Structural MRI, Functional MRI, and Magnetic Resonance Spectroscopy

Brief Summary: Urea cycle disorders (UCDs) are a group of rare inherited metabolism disorders. The purpose of this study is to evaluate how UCD-related neurologic injuries affect adults with one of the most common types of UCD.

Detailed Summary:

UCDs are a group of rare genetic diseases that affect how protein is broken down in the body. The cause of UCDs is a deficiency in one of eight enzymes responsible for removing ammonia, a waste product of protein metabolism, from the bloodstream. Normally, ammonia is converted into urea and then removed from the body in the form of urine. However, in people with UCDs, ammonia accumulates unchecked and is not removed from the body. Toxic levels of ammonia can build up and cause irreversible neurologic damage that can affect metabolism, cognition, sensation, and movement. This study will focus on the most common enzyme disorder among UCDs, ornithine transcarbamylase deficiency (OTCD), a disorder inherited from mothers. Using different types of magnetic resonance imaging (MRI), this study will evaluate how UCD-related neurologic injuries affect metabolism, cognition, sensation, and movement in adults with OTCD.

Participants in this study will attend an initial study visit that will include a review of medical history, current symptoms, impairments, and diet history; urine and blood collection; a physical exam; a full neurological exam; and cognitive and motor testing. During this visit, participants will undergo imaging studies and additional cognitive and motor testing over a 2- to 3-day period. This will include standard MRI studies and four sessions consisting of functional MRI (fMRI), diffusion tensor imaging, and 1H magnetic resonance spectroscopy. For the fMRI study, participants perform various motor and behavioral tasks while in the imaging scanner. Magnetic resonance spectroscopy (MRS) is used to study and evaluate the chemical makeup of specific brain areas. Diffusion tensor imaging is used to assess myelination of major brain pathways and their alteration in disease states. This study will involve one-time participation. There will be no follow-up visits for this
Sponsor: Andrea Gropman

Current Primary Outcome:

  • Concentration of Glutamine and Myoinositol by MRS [ Time Frame: one time measurement at study baseline ]

    Concentration based on area under curve on 1H MRS and quantitated by LCModel. A metabolite's tissue concentration is related to the integrated amplitude of the MRS signal it produces. Integrated amplitude is the area under the MRS signal curve. While MRS signals are usually acquired in the time domain as free induction decays or echoes, they are usually viewed and analyzed in the frequency domain. The frequency domain representation is derived from the acquired time domain data by the Fourier Transform. The protocol we use selects 257 averages. This means, 257 free induction decays. The machine summates the data at each time point to generate one value for the area under the curve. Therefore, we don't have the measurement at each time point.

    Furthermore, we measured voxels in two different brain areas containing different kinds of brain matter: one voxel was located in posterior cingulate gray matter (PCGM) and the other in parietal white matter (PWM).

  • Functional MRI Activation in N-Back Tast [ Time Frame: one time measurement at study baseline ]
    Measure of blood oxygen level dependent (BOLD) signal of OTCD patients and healthy controls during an N-Back task comparing 2-back and 1-back conditions. This contrast was created for each participant using SPM and then entered into a group analysis in which we compare percent signal change between groups. Therefore, we never see BOLD signal change at the individual level, which is why we never see "scores" or numbers at the individual level and we cannot calculate

    Original Primary Outcome:

    Current Secondary Outcome:

    Original Secondary Outcome:

    Information By: Children's Research Institute

    Dates:
    Date Received: May 11, 2007
    Date Started: March 2007
    Date Completion:
    Last Updated: May 28, 2015
    Last Verified: May 2015