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 argl 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.