Determination of Guanidino Compounds in Plasma and Urine of Patients with Argininemia before and during Therapy

Abstract

The first clinical and biochemical description of two sisters affected with argininemia, last of the five primary disorders of the urea cycle, was published in 1969^1–3. A third sister homozygote was described shortly after birth five years later⁴. Five other families including eight cases have been reported in the literature^5–10. The first clinical symptoms seen in patients with argininemia are irritability, coma and epilepsy. The children show also pyramidal spasticity and mental retardation. All the patients described are still alive. The patient’s biochemistry is characterized by an arginase deficiency in liver shown after biopsy as well as in erythrocytes and leucocytes. As a consequence to this arginase deficiency, the patients accumulate arginine in their cells and biological fluids. The arginine accumulation leads to an increase of its catabolites: the guanidino compounds. Already in 1972 it was reported that guanidinoacetic acid, N-α-acetylarginine, argininic acid, γ-guanidinobutyric acid, arginine and an unknown guanidino compound (later identified as being γ-keto-δ-guanidinovaleric acid¹¹) were elevated in urine of these patients¹². These determinations were done applying the colorimetric Sakaguchi detection method.