Argininosuccinic acidemia

Matthias Zielonka MD (

Dr. Zielonka of University Children’s Hospital Heidelberg has no relevant financial relationships to disclose.

Stefan Kolker MD (

Dr. Kolker of University Children's Hospital Heidelberg has no relevant financial relationships to disclose.

Barry Wolf MD PhD, editor. (Dr. Wolf of Lurie Children's Hospital of Chicago has no relevant financial relationships to disclose.)
Originally released April 24, 1995; last updated March 4, 2018; expires March 4, 2021

This article includes discussion of argininosuccinic acidemia, argininosuccinase deficiency, and argininosuccinic aciduria. The foregoing terms may include synonyms, similar disorders, variations in usage, and abbreviations.


Argininosuccinic aciduria is an inherited urea cycle disorder caused by argininosuccinic acid lyase deficiency. Patients can present with hyperammonemic encephalopathy at any age, resulting in brain damage or even death if treatment is inadequate or delayed. Patients may also develop hepatomegaly, progressive liver fibrosis, and liver function abnormalities, but they can also present with intellectual disabilities only. The disease can be detected by expanded newborn screening. Treatment consists of low-protein diet, ammonia scavengers, and L-arginine. Liver transplantation cures the hyperammonemia but does not prevent production of argininosuccinic acid in nonhepatic tissues. The authors discuss the results of an observational study, which demonstrated that neurologic involvement is similar in patients with early- and late- onset disease and does not correlate with plasma biomarkers (ammonium and argininosuccinate), whereas liver, kidney, and gut are more severely involved in the early-onset than the late-onset group, implicating discrepant pathomechanisms.

Historical note and terminology

Argininosuccinic acidemia was first described in 1958 by Allan and colleagues (Allan et al 1958). Its name derives from the marked elevation of argininosuccinic acid in blood of affected individuals. This disorder has also been called argininosuccinic aciduria because of the increased excretion of argininosuccinic acid in urine, and argininosuccinate lyase deficiency to denote its enzyme deficiency.

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