Spastic gait, intellectual disability and seizures due to a rare mutation causing hyperargininemia.

Hyperargininemia is an autosomal recessive disorder caused by a defect in the arginase I enzyme. We present a case of a 20-year-old male with severe spastic gait, intellectual disability and seizures. Metabolic tests revealed high levels of arginine in blood serum. Hyperargininemia was attributed to a likely pathogenic rare mutation of ARG1 gene [Chr6: g131905002_131905002 G>A (p.Arg308Gln) homozygous] detected in Whole Exome Sequencing resulting in deficiency in arginase I enzyme. Following the diagnosis, the patient has been treated with low protein diet, aminoacid and vitamin supplements. The accumulation of arginine, may contribute to the pathogenesis of severe neurological manifestations, however, low protein intake diet may lead to a favorable outcome. Therefore, clinicians should screen for hyperargininemia in early childhood in case of strong clinical suspicion.