Traits

Traits linked to ALAD

aminolevulinate dehydratase

The Human Phenotype Ontology links 52 traits to ALAD, 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
Abnormality of the nervous system	Often (30–79%)
Peripheral neuropathy	Often (30–79%)
Abnormal fear-induced behavior	Sometimes (5–29%)
Abnormal gait	Sometimes (5–29%)
Agitation	Sometimes (5–29%)
Anxiety	Sometimes (5–29%)
Autism	Sometimes (5–29%)
Confusion	Sometimes (5–29%)
Damage to nerves that sense feeling	Sometimes (5–29%)
Delirium	Sometimes (5–29%)
Depression	Sometimes (5–29%)
Difficulty articulating speech	Sometimes (5–29%)
Fluctuations in consciousness	Sometimes (5–29%)
Hallucinations	Sometimes (5–29%)
Intellectual disability, mild	Sometimes (5–29%)
Lack of feeling, emotion, interest	Sometimes (5–29%)
Motor polyneuropathy	Sometimes (5–29%)
Peripheral nerve disease	Sometimes (5–29%)
Restlessness	Sometimes (5–29%)
Paralysis	Not recorded
Pins and needles feeling	Not recorded

Abnormality of the digestive system

Trait	How often it is seen
Abdominal pain	Often (30–79%)
Abdominal bloating	Sometimes (5–29%)
Constipation	Sometimes (5–29%)
Diarrhea	Sometimes (5–29%)
Episodic vomiting	Sometimes (5–29%)
Nausea	Sometimes (5–29%)
Abdominal colic	Not recorded
Vomiting	Not recorded

Laboratory abnormality

Trait	How often it is seen
Elevated urinary delta-aminolevulinic acid	Always
Abnormal circulating enzyme concentration or activity	Very often (80–99%)
Abnormal circulating porphyrin concentration	Often (30–79%)
Increased erythrocyte protoporphyrin concentration	Often (30–79%)
Increased fecal coproporphyrin 3	Often (30–79%)
Increased urinary porphobilinogen	Often (30–79%)
Purple urine	Often (30–79%)
Low blood sodium levels	Sometimes (5–29%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Low muscle tone	Always
Respiratory paralysis	Always
Muscle weakness	Often (30–79%)
Functional motor deficit	Sometimes (5–29%)

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Abnormal erythrocyte enzyme concentration or activity	Often (30–79%)
Myeloproliferative disorder	Sometimes (5–29%)
Hemolytic anemia	Not recorded

Abnormality of the respiratory system

Trait	How often it is seen
Abnormality of the respiratory system	Sometimes (5–29%)
Respiratory function loss	Sometimes (5–29%)
Ventilator dependence with inability to wean	Sometimes (5–29%)

Abnormality of limbs

Trait	How often it is seen
Ankle flexion contracture	Sometimes (5–29%)
Limb muscle weakness	Sometimes (5–29%)

Abnormality of the ear

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

Abnormality of the integument

Trait	How often it is seen
Abnormal skin structure	Not recorded

Growth abnormality

Trait	How often it is seen
Faltering weight	Always

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 ALAD and how often each is seen. Find out more at hpo.jax.org.

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