Propionic Acidemia: Gray Matter Disease Meets Subcortical Leukodystrophy.

Area of Science:

• Neurology
• Radiology
• Metabolic Disorders

Background:

• Propionic acidemia (PA) is a rare metabolic disorder.
• Existing imaging literature primarily focuses on deep gray matter changes in PA.

Purpose of the Study:

• To systematically analyze the spectrum and patterns of MRI changes in propionic acidemia.
• To characterize the evolution of brain lesions in PA patients.

Main Methods:

• Retrospective analysis of 45 MRI scans from 13 patients with PA (age range: 0.31–33.2 years).
• Systematic evaluation of deep and cortical gray matter, white matter, and other brain structures.

Main Results:

• Deep and cortical gray matter changes were linked to acute metabolic decompensation.
• Striatal involvement (10/13) and transient pallidal changes in infants were observed.
• Subcortical leukoencephalopathy was characteristic in older children (≥9 years), potentially improving over time.
• Cerebellar watershed injury and cortico-subcortical changes were more frequent with seizures during decompensation.

Conclusions:

• MRI findings in propionic acidemia are diverse, extending beyond deep gray matter.
• Subcortical white matter changes are a hallmark in older PA patients and may show improvement.
• Transient pallidal changes in infants suggest myelin-related processes.
• Seizures during decompensation correlate with specific brain injuries.