Traits

Traits linked to PHKA1

phosphorylase kinase regulatory subunit alpha 1

The Human Phenotype Ontology links 29 traits to PHKA1, by body system: features seen in people with one of the gene's rare conditions.

Abnormality of the musculoskeletal system

Trait	How often it is seen
Distal muscle wasting	Always
Muscle fiber necrosis	Always
Weakness of outermost muscles	Always
Progressive muscle weakness	Very often (80–99%)
EMG: myopathic abnormalities	Often (30–79%)
Camptocormia	Sometimes (5–29%)
Difficulty walking up stairs	Sometimes (5–29%)
Gowers sign	Sometimes (5–29%)
Muscle degeneration	Sometimes (5–29%)
Muscle spasm	Sometimes (5–29%)
Exercise-induced muscle stiffness	Not recorded
Muscle weakness	Not recorded

Laboratory abnormality

Trait	How often it is seen
Elevated blood creatine phosphokinase	Always
Glycogen accumulation in muscle fiber lysosomes	Always
Increased muscle glycogen content	Always
Low blood sugar	Always
Reduced muscle phosphorylase kinase activity	Always
Myoglobinuria	Sometimes (5–29%)
Exercise-induced myoglobinuria	Not recorded
Reduced tissue phosphorylase kinase activity	Not recorded

Constitutional symptom

Trait	How often it is seen
Decreased ability to exercise	Always
Fatigue	Often (30–79%)
Muscle ache	Often (30–79%)
Exercise-induced muscle pain	Not recorded

Abnormality of limbs

Trait	How often it is seen
Lower limb muscle weakness	Always
Pelvic girdle muscle weakness	Always
Quadriceps weakness	Always

Abnormality of the nervous system

Trait	How often it is seen
Abnormal gait	Sometimes (5–29%)
Decreased reflex response	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 PHKA1 and how often each is seen. Find out more at hpo.jax.org.

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