Traits

Traits linked to IARS1

isoleucyl-tRNA synthetase 1

The Human Phenotype Ontology links 51 traits to IARS1, by body system: features seen in people with one of the gene's rare conditions.

IARS1

Laboratory abnormality

Trait	How often it is seen
Conjugated hyperbilirubinemia	Always
Decreased serum zinc	Always
Elevated alkaline phosphatase	Always
Elevated gamma-glutamyltransferase level	Always
High blood ammonia levels	Always
Low albumin	Always
Low blood sugar	Always
High liver enzymes	Very often (80–99%)
Elevated circulating alanine aminotransferase concentration	Often (30–79%)
Elevated circulating aspartate aminotransferase concentration	Often (30–79%)
Fatty infiltration of liver	Often (30–79%)
Abnormality of vitamin D metabolism	Sometimes (5–29%)
Diabetes mellitus	Sometimes (5–29%)

Abnormality of the digestive system

Trait	How often it is seen
Impaired release of bile from liver	Always
Jaundice	Always
Feeding difficulties	Often (30–79%)
Hepatic fibrosis	Often (30–79%)
Slowed or blocked flow of bile from liver	Often (30–79%)
Inflammation of the esophagus	Sometimes (5–29%)
Liver failure	Sometimes (5–29%)
Decreased liver function	Not recorded

Abnormality of the nervous system

Trait	How often it is seen
Intellectual disability	Always
Global developmental delay	Very often (80–99%)
Absent speech development	Often (30–79%)
Epilepsy	Often (30–79%)
Autism spectrum disorder	Sometimes (5–29%)
Brain imaging abnormality	Sometimes (5–29%)
Mild global developmental delay	Sometimes (5–29%)

Abnormality of head or neck

Trait	How often it is seen
Development of small head that was not present at birth	Always
Round face	Always
Small head present at birth	Always
Full cheeks	Often (30–79%)
Abnormally small head	Sometimes (5–29%)

Growth abnormality

Trait	How often it is seen
Faltering weight	Always
Growth delay as children	Always
Prenatal growth deficiency	Always
Small for gestational age	Always
Growth delay	Very often (80–99%)

Abnormality of the integument

Trait	How often it is seen
Dermal translucency	Sometimes (5–29%)
Hyperelastic skin	Sometimes (5–29%)
Soft, doughy skin	Sometimes (5–29%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Double-Jointed	Always
Involuntary muscle stiffness, contraction, or spasm	Often (30–79%)
Low muscle tone	Often (30–79%)

Abnormality of the genitourinary system

Trait	How often it is seen
Duplicated collecting system	Always
Hydronephrosis	Always

Abnormality of limbs

Trait	How often it is seen
Drumstick shaped digital bones	Sometimes (5–29%)

Abnormality of prenatal development or birth

Trait	How often it is seen
Low levels of amniotic fluid	Always

Abnormality of the cardiovascular system

Trait	How often it is seen
Enlarged liver and spleen	Sometimes (5–29%)

Abnormality of the ear

Trait	How often it is seen
Sensorineural hearing impairment	Often (30–79%)

Abnormality of the immune system

Trait	How often it is seen
Recurrent infections	Often (30–79%)

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 IARS1 and how often each is seen. Find out more at hpo.jax.org.

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