Traits

Traits linked to VRK1

VRK serine/threonine kinase 1

The Human Phenotype Ontology links 70 traits to VRK1, 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	Always
Brisk reflexes	Always
Decreased number of peripheral myelinated nerve fibers	Always
Difficulty sleeping	Always
Motor axonal neuropathy	Always
Motor delay	Always
Muscle twitch	Always
Small cerebellum	Always
Absent/small cerebellum	Very often (80–99%)
Decreased reflex response	Very often (80–99%)
Degeneration of anterior horn cells	Very often (80–99%)
Global developmental delay	Very often (80–99%)
Decrease in size of the outer layer of the brain due to loss of brain cells	Often (30–79%)
Demyelinating peripheral neuropathy	Often (30–79%)
Hand tremor	Often (30–79%)
Hypoplasia of the pons	Often (30–79%)
Intellectual disability, mild	Often (30–79%)
Lateral ventricle dilatation	Often (30–79%)
Limb ataxia	Often (30–79%)
Nerve damage causing decreased feeling and movement	Often (30–79%)
Sensory axonal neuropathy	Often (30–79%)
Simplified gyral pattern	Often (30–79%)
Babinski sign	Sometimes (5–29%)
Cerebellar cyst	Sometimes (5–29%)
Delayed ability to roll over	Sometimes (5–29%)
Delayed ability to sit	Sometimes (5–29%)
Epilepsy	Sometimes (5–29%)
Increased reflexes	Sometimes (5–29%)
Peripheral axonal neuropathy	Sometimes (5–29%)
Thin corpus callosum	Sometimes (5–29%)
Basal ganglia gliosis	Not recorded
Hypoplasia of the ventral pons	Not recorded
Intellectual disability	Not recorded
Neuronal loss in basal ganglia	Not recorded

Abnormality of the musculoskeletal system

Trait	How often it is seen
Increased endomysial connective tissue	Always
Increased variability in muscle fiber diameter	Always
Low muscle tone	Very often (80–99%)
Muscle degeneration	Very often (80–99%)
Muscle weakness	Very often (80–99%)
Weakness of outermost muscles	Very often (80–99%)
Distal muscle wasting	Often (30–79%)
Muscle weakness between ribs	Often (30–79%)
Involuntary muscle stiffness, contraction, or spasm	Sometimes (5–29%)
Proximal neurogenic muscle weakness	Sometimes (5–29%)
Scoliosis	Sometimes (5–29%)
Arthrogryposis multiplex congenita	Rarely (1–4%)
Congenital contracture	Not recorded
EMG: neuropathic changes	Not recorded
Spinal muscle degeneration	Not recorded

Abnormality of the eye

Trait	How often it is seen
Involuntary, rapid, rhythmic eye movements	Often (30–79%)
Optic atrophy	Often (30–79%)
Progressive loss of vision	Often (30–79%)
Cross-eyed	Sometimes (5–29%)
Inward turning cross eyed	Rarely (1–4%)

Abnormality of head or neck

Trait	How often it is seen
Abnormally small head	Always
Enlarged cisterna magna	Always
Progressively abnormally small cranium	Often (30–79%)
Tongue twitching	Often (30–79%)

Abnormality of limbs

Trait	How often it is seen
Club feet	Always
High-arched foot	Often (30–79%)
Hammertoe	Sometimes (5–29%)
Abnormal feet structure	Not recorded

Abnormality of the digestive system

Trait	How often it is seen
Poor swallowing	Always
Feeding difficulties	Often (30–79%)
Poor suck	Often (30–79%)
Feeding difficulties in infancy	Not recorded

Abnormality of the respiratory system

Trait	How often it is seen
Respiratory failure	Very often (80–99%)
Congenital laryngeal stridor	Sometimes (5–29%)
Respiratory function loss	Not recorded

Growth abnormality

Trait	How often it is seen
Faltering weight	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 VRK1 and how often each is seen. Find out more at hpo.jax.org.

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