Neurophysiological characteristics in argininemia: a case report

Area of Science:

• Biochemistry
• Genetics
• Neurology

Background:

• Argininemia is a rare inherited metabolic disorder caused by mutations in the ARG1 gene, leading to progressive spastic paraplegia.
• The exact pathophysiology of argininemia remains unclear, though liver transplantation (LT) has shown promise in halting disease progression.

Observation:

• A 13-year-old male patient presented with progressive neurological impairment due to argininemia, confirmed by elevated plasma arginine and ARG1 gene mutation.
• Clinical evaluation included Spastic Paraplegia Rating Scale (SPRS), motor evoked potentials (MEPs), somatosensory evoked potentials (SEPs), F-wave, electromyography, nerve conduction velocity (NCV), and brain MRI.
• Neurophysiological testing revealed abnormalities primarily in MEPs, indicating pyramidal tract dysfunction in the lower limbs, alongside mild cerebellar atrophy on MRI.

Findings:

• The patient showed poor response to conventional treatments like protein restriction and sodium benzoate.
• Progressive deterioration of speech, irritability, and dyskinesia necessitated living-donor LT (LDLT).
• Six months post-LDLT, the patient exhibited significant symptom improvement, with a 50% reduction in spasticity severity score.

Implications:

• LDLT is a viable and effective treatment for argininemia, significantly improving neurological function and quality of life.
• Phenotypic similarities between argininemia and other urea cycle disorders suggest shared underlying mechanisms impacting corticospinal tract integrity.
• Further research into these common mechanisms could reveal novel therapeutic targets for neurodegenerative disorders affecting the urea cycle.