Traits

Traits linked to KARS1

lysyl-tRNA synthetase 1

The Human Phenotype Ontology links 73 traits to KARS1, by body system: features seen in people with one of the gene's rare conditions.

KARS1

Abnormality of the nervous system

Trait	How often it is seen
Abnormal pyramidal sign	Always
Akinesia	Always
Ataxia	Always
Cognitive impairment	Always
Decreased compound muscle action potential amplitude	Always
Delayed ability to walk	Always
Dystonia	Always
Elevated brain lactate level by MRS	Always
Epilepsy	Always
Generalized tonic seizure	Always
Global developmental delay	Always
Hypointensity of cerebral white matter on MRI	Always
Leukodystrophy	Always
Leukoencephalopathy	Always
Loss of developmental milestones	Always
Mental deterioration	Always
Motor delay	Always
Peripheral axonal neuropathy	Always
Self-injurious behavior	Always
Severe global developmental delay	Always
Worsening neurological symptoms	Always
Absent speech development	Very often (80–99%)
Absent brainstem auditory responses	Often (30–79%)
Diffuse cerebral atrophy	Often (30–79%)
Gliosis	Often (30–79%)
Head titubation	Often (30–79%)
Increased reflexes	Often (30–79%)
Small cerebellum	Often (30–79%)
Absent reflexes	Not recorded
Decreased reflex response	Not recorded
Decreased sensation in extremities	Not recorded
High stepping	Not recorded

Abnormality of the musculoskeletal system

Trait	How often it is seen
Abnormal deposits of calcium in the brain	Always
Delayed bone maturation	Always
Spastic tetraplegia	Always
Low muscle tone	Often (30–79%)
Low muscle tone in trunk	Often (30–79%)
Subcortical white matter calcifications	Often (30–79%)
Spasticity and rigidity of muscles	Sometimes (5–29%)
Harder, denser, fracture-prone bones	Not recorded

Laboratory abnormality

Trait	How often it is seen
Decreased CSF biopterin level	Always
High levels of ketone bodies	Always
Higher than normal levels of lactate in blood	Always
Increased blood alanine	Always
Mild proteinuria	Always
Elevated serum ferritin	Often (30–79%)
Increased circulating pyruvate concentration	Sometimes (5–29%)

Abnormality of the ear

Trait	How often it is seen
Congenital sensorineural hearing impairment	Always
Hearing impairment	Always
Profound sensorineural hearing impairment	Always
Sensorineural hearing impairment	Always
Vestibular schwannoma	Always
Vestibular areflexia	Often (30–79%)

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Hypochromic microcytic anemia	Always
Low number of red blood cells or hemoglobin	Often (30–79%)
Low platelet count	Sometimes (5–29%)

Abnormality of head or neck

Trait	How often it is seen
Abnormally small head	Always
Long philtrum	Always
Narrow mouth	Always

Growth abnormality

Trait	How often it is seen
Faltering weight	Always
Growth delay	Always
Small for gestational age	Always

Abnormality of limbs

Trait	How often it is seen
Foot drop	Not recorded
High-arched foot	Not recorded

Abnormality of the digestive system

Trait	How often it is seen
Vomiting	Always
Diarrhea	Sometimes (5–29%)

Abnormality of the eye

Trait	How often it is seen
Involuntary, rapid, rhythmic eye movements	Always
Progressive loss of vision	Always

Abnormal cellular phenotype

Trait	How often it is seen
Decreased activity of mitochondrial respiratory chain	Always

Abnormality of the endocrine system

Trait	How often it is seen
Underactive thyroid	Always

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
Baby eczema	Often (30–79%)

Abnormality of the respiratory system

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

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 KARS1 and how often each is seen. Find out more at hpo.jax.org.

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