Argininosuccinic acidemia

Stefan Kolker MD (Dr. Kolker of University Children's Hospital has no relevant financial relationships to disclose.)
Barry Wolf MD PhD, editor. (Dr. Wolf of Henry Ford Hospital has no relevant financial relationships to disclose.)
Originally released April 24, 1995; last updated February 27, 2017; expires February 27, 2020

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 author discusses the results of a metaanalysis of neonatal mortality and outcome in early-onset urea cycle disorders, the potential benefit of newborn screening, and in vitro evidence for a novel treatment strategy.

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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