Brain MR spectroscopic abnormalities in "MRI-negative" tuberous sclerosis complex patients

Area of Science:

• Neurology
• Biochemistry
• Medical Imaging

Background:

• Tuberous Sclerosis Complex (TSC) affects approximately 50,000 individuals in the US.
• A subset of TSC patients (~5-10%) are classified as "MRI-negative."
• The presence of metabolic abnormalities in "MRI-negative" TSC patients remains under investigation.

Purpose of the Study:

• To investigate metabolic abnormalities in "MRI-negative" Tuberous Sclerosis Complex (TSC) patients.
• To test the hypothesis that these patients exhibit detectable metabolic differences despite negative MRI findings.

Main Methods:

• Proton MR spectroscopy was employed to assess brain metabolite concentrations.
• Gray matter (GM) and white matter (WM) levels of N-acetylaspartate (NAA), myo-inositol (mI), creatine (Cr), and choline (Cho) were measured.
• Metabolite levels in two "MRI-negative" female TSC patients were compared to age-matched controls.

Main Results:

• Pediatric patient's metabolite levels (NAA, Cr, Cho, mI) were comparable to controls.
• The adult patient showed a 17% decrease in white matter N-acetylaspartate (NAA) and a 16% increase in white matter choline (Cho) compared to healthy adult means.
• These adult patient findings fell outside the 90% prediction intervals for healthy individuals.

Conclusions:

• Metabolic abnormalities may be present in "MRI-negative" TSC patients, particularly with longer disease duration.
• Observed white matter changes in the adult patient suggest potential axonal dysfunction and demyelination.
• The TSC2 gene mutation may be associated with these observed metabolic alterations.