Traits

Traits linked to ASL

argininosuccinate lyase

The Human Phenotype Ontology links 63 traits to ASL, by body system: features seen in people with one of the gene's rare conditions.

Abnormality of the nervous system

Trait	How often it is seen
Ataxia	Often (30–79%)
Drowsiness	Often (30–79%)
EEG abnormality	Often (30–79%)
Epilepsy	Often (30–79%)
Intellectual disability	Often (30–79%)
Lethargy	Often (30–79%)
Neurodevelopmental delay	Often (30–79%)
Specific learning disability	Often (30–79%)
Attention deficit	Sometimes (5–29%)
Delayed speech and language development	Sometimes (5–29%)
Dystonia	Sometimes (5–29%)
Focal T2 hyperintense basal ganglia lesion	Sometimes (5–29%)
Generalized brain degeneration	Sometimes (5–29%)
Motor delay	Sometimes (5–29%)
Periventricular leukomalacia	Sometimes (5–29%)
Psychosis	Sometimes (5–29%)
Self-mutilation	Sometimes (5–29%)
Tremor	Sometimes (5–29%)
Coma	Not recorded
Global developmental delay	Not recorded
Irritability	Not recorded

Laboratory abnormality

Trait	How often it is seen
Elevated CSF argininosuccinic acid concentration	Always
Abnormal urinary amino-acid findings	Very often (80–99%)
High blood ammonia levels	Very often (80–99%)
High plasma glutamine	Very often (80–99%)
Low blood arginine levels	Very often (80–99%)
Argininosuccinic aciduria	Often (30–79%)
Elevated circulating citrulline concentration	Often (30–79%)
High liver enzymes	Often (30–79%)
Increased circulating argininosuccinic acid	Often (30–79%)
Respiratory alkalosis	Often (30–79%)
High urine orotic acid levels	Sometimes (5–29%)
Increased plasma triglycerides	Sometimes (5–29%)
Low blood potassium levels	Sometimes (5–29%)
Brain swelling	Not recorded
Elevated circulating aspartate aminotransferase concentration	Not recorded
Episodic ammonia intoxication	Not recorded

Abnormality of the digestive system

Trait	How often it is seen
Enlarged liver	Often (30–79%)
Vomiting	Often (30–79%)
Chronic pancreas inflammation	Sometimes (5–29%)
Diarrhea	Sometimes (5–29%)
Hepatic fibrosis	Sometimes (5–29%)
Liver failure	Sometimes (5–29%)
Scar tissue replaces healthy tissue in the liver	Sometimes (5–29%)
Hepatocellular carcinoma	Rarely (1–4%)
Feeding difficulties in infancy	Not recorded
Protein avoidance	Not recorded

Abnormality of the integument

Trait	How often it is seen
Monilethrix	Often (30–79%)
Abnormal hair quantity	Sometimes (5–29%)
Flattened and twisted hair	Sometimes (5–29%)
Patchy baldness	Sometimes (5–29%)
Trichorrhexis nodosa	Sometimes (5–29%)
Brittle hair	Not recorded
Dry hair	Not recorded

Abnormality of the cardiovascular system

Trait	How often it is seen
High blood pressure	Often (30–79%)
Abnormal heart rate	Sometimes (5–29%)

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Increased number of platelets in blood	Sometimes (5–29%)

Abnormality of head or neck

Trait	How often it is seen
Dental cavities	Sometimes (5–29%)

Abnormality of the genitourinary system

Trait	How often it is seen
Renal failure	Sometimes (5–29%)

Abnormality of the immune system

Trait	How often it is seen
Eczema	Sometimes (5–29%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Muscle weakness	Sometimes (5–29%)

Abnormality of the respiratory system

Trait	How often it is seen
Increased respiratory rate or depth of breathing	Often (30–79%)

Growth abnormality

Trait	How often it is seen
Faltering weight	Not recorded

How often is among people with one of the gene's conditions, the most often across them, as the Human Phenotype Ontology records it. These pages describe traits and the research behind them; they are not a diagnosis, and a doctor or genetic counsellor is the person to ask about symptoms.

Where this comes from

The Human Phenotype Ontology, release 2026-09-01: the traits linked to ASL and how often each is seen. Find out more at hpo.jax.org.

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