Amino Acid Disorders

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Disease Name Argininosuccinyl-CoA lyase deficiency
Alternate name(s) Argininosuccinase deficiency, Argininosuccinic aciduria, Argininosuccinic acid lyase deficiency, ASL deficiency
Acronym ASAL
Disease Classification Amino Acid Disorder
Variants Yes
Variant name Late onset form
Symptom onset Neonatal onset is typical, although later-onset may occur.
Symptoms Anorexia, vomiting, lethargy, seizures and coma possibly leading to death.
Natural history without treatment Mental and physical retardation due to hyperammonemia, cyclic vomiting, seizures, cerebral edema and trichorrhexis nodosa. Coma and death possible.
Natural history with treatment Normal mental and physical development is possible if treatment is initiated before hyperammonemic crisis.
Treatment Protein restricted diet, arginine supplementation to help complete the urea cycle, essential amino acid supplementation, ammonia scavenging drugs in some cases and supplemental carnitine if patient has a secondary deficiency.
Other Enzyme is genetically heterogeneous and patients may present in infancy/childhood with MR or seizures.
Physical phenotype Trichorrhexis nodosa (short, dry, brittle hair) in older patients.
Inheritance Autosomal recessive
General population incidence 1:70,000
Ethnic differences No
Ethnic incidence N/A
Enzyme location Erythrocytes, liver and fibroblasts
Enzyme Function Catalyzes the conversion of argininosuccinate to fumurate and arginine as part of the urea cycle.
Missing Enzyme Argininosuccinate lyase
Metabolite changes Hyperammonemia
Gene ASL
Gene location 7q11.2
DNA testing available No
DNA testing detail No common mutation known. More that 25 mutations detected.
Prenatal testing Enzyme assay in cultured amniocytes. DNA possible if mutations known. Analyte testing of amniocytes.
MS/MS Profile Citrulline is elevated, may show elevated argininosuccinic peak.
Genetests Link
Support Group National Urea Cycle Disorders Foundation

National Coalition for PKU and Allied Disorders

Children Living with Inherited Metabolic Diseases
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