Hyperargininemia mimicking spastic cerebral palsy: case report

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Abstract

Case Presentation: A case of a metabolic disease of the urea cycle - hyperargininemia, which mimics spastic cerebral palsy, in addition to reviewing the medical literature. Female, six-year-old patient, with no risk factors for brain injury, presented with spastic paraparesis, compromising gait, associated with cognitive and language impairment. Brain MRI showed cerebral atrophy. The initial diagnosis of spastic diplegic cerebral palsy, GMFCS IV, was excluded 3 years later, considering the clinical evolution and the amino acid profile by mass spectrometry, which showed an increase in plasma arginine concentration, compatible with the diagnosis of hyperargininemia. Sequencing in the ARG1 gene confirmed 2 pathogenic variants.

Discussion: Hyperargininemia is a rare, autosomal recessive metabolic disorder caused by an inherited deficiency of hepatocyte arginase due to a defect in the ARG1 gene. Arginase is the final enzyme in the urea cycle that catalyzes the hydrolysis of arginine to ornithine and urea. This genetic disorder is caused by more than 40 mutations found throughout the ARG1 gene, resulting in partial or complete loss of enzyme function. With the application of liquid chromatography-tandem mass spectrometry in selective screening and neonatal screening for inborn errors of metabolism, an increasing number of patients with argininemia are detected in the asymptomatic or early stages Early diagnosis and a protein-restricted diet with citrulline and benzoate supplements may contribute to improving the patient's prognosis.

Final Comments: Confirmation of a genetic diagnosis has relevant implications for the patient and family, and some specific metabolic conditions may improve symptoms and developmental outcome. Genetic counseling can prevent a recurrence of the disease in the family and provide information to other members at risk. Several genetic problems can have clinical features that mimic cerebral palsy. It is essential to insist on the search for an accurate etiological diagnosis, especially among patients who do not have risk factors that justify the neurological condition.

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Artikel online veröffentlicht:
12. Mai 2025