Traits

Traits linked to XK

X-linked Kx blood group antigen, Kell and VPS13A binding protein

The Human Phenotype Ontology links 29 traits to XK, 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
Chorea	Very often (80–99%)
Difficulty articulating speech	Often (30–79%)
Dystonia	Often (30–79%)
Epilepsy	Often (30–79%)
Impaired vibration sensation at ankles	Often (30–79%)
Anxiety	Not recorded
Depression	Not recorded
Disorder of involuntary muscle movements	Not recorded
Generalized-onset seizure	Not recorded
Motor axonal neuropathy	Not recorded
Obsessive compulsive behavior	Not recorded
Personality disorder	Not recorded

Laboratory abnormality

Trait	How often it is seen
Elevated blood creatine phosphokinase	Always
Decreased circulating haptoglobin concentration	Very often (80–99%)
Increased circulating lactate dehydrogenase concentration	Very often (80–99%)
Elevated circulating alanine aminotransferase concentration	Often (30–79%)
Elevated circulating aspartate aminotransferase concentration	Often (30–79%)
Elevated gamma-glutamyltransferase level	Often (30–79%)

Abnormality of the cardiovascular system

Trait	How often it is seen
Increased spleen size	Often (30–79%)
Disease of the heart muscle	Sometimes (5–29%)
Quivering upper heart chambers resulting in irregular heartbeat	Sometimes (5–29%)
Stretched and thinned heart muscle	Sometimes (5–29%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Muscle tissue disease	Very often (80–99%)
Muscle weakness	Often (30–79%)
Breakdown of skeletal muscle	Sometimes (5–29%)

Abnormality of limbs

Trait	How often it is seen
Absent ankle reflexes	Very often (80–99%)
Areflexia of upper limbs	Often (30–79%)

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Acanthocytosis	Always

Abnormality of the digestive system

Trait	How often it is seen
Enlarged liver	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 XK and how often each is seen. Find out more at hpo.jax.org.

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