Hyperargininemic Encephalopathy with Unique Clinical Presentation and Novel Genetic Mutations

Hyperargininemia is a urea cycle disorder that has rarely been reported in adults. We present a case of arginase deficiency disorder in a 32-year man with metabolic encephalopathy. He presented with progressive limb spasticity, changes in personality, cognitive decline (impaired judgement, executive and language dysfunction) and pseudo-bulbar affect. He deteriorated to an akinetic mute and rigid state. MRI brain was suggestive of a metabolic disorder. Hyperammonemia was present, blood arginine levels were elevated, and serum arginase levels were reduced. The standard argI gene mutations were absent but rs2781666 (G/T) and rs2608897 (C/T) variations were noted in this patient. Hyperargininemic encephalopathy may present in adults and with atypical features. It should be kept in the differential diagnosis of metabolic encephalopathy in adults. Key Words: Metabolic encephalopathy, Pseudobulbar affect, Arginase deficiency, Hyperammonemia, Urea cycle.