Traits

Traits linked to SIGMAR1

sigma receptor chaperone 1

The Human Phenotype Ontology links 60 traits to SIGMAR1, 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
Brisk knee jerk	Always
Decreased compound muscle action potential amplitude	Always
Decreased motor nerve conduction velocity	Always
Increased reflexes	Always
Lou Gehrig's disease	Very often (80–99%)
Abnormal gait	Often (30–79%)
Abnormal speech pattern	Often (30–79%)
Arm dystonia	Often (30–79%)
Babinski sign	Often (30–79%)
Brisk reflexes	Often (30–79%)
Bulbar signs	Often (30–79%)
CNS hypomyelination	Often (30–79%)
Delayed ability to walk	Often (30–79%)
Dystonia	Often (30–79%)
Inability to walk	Often (30–79%)
Loss of ability to walk	Often (30–79%)
Abnormality of the cerebellum	Sometimes (5–29%)
Ataxia	Sometimes (5–29%)
Axial dystonia	Sometimes (5–29%)
Behavioral abnormality	Sometimes (5–29%)
Chorea	Sometimes (5–29%)
Clonus	Sometimes (5–29%)
Cognitive impairment	Sometimes (5–29%)
Global developmental delay	Sometimes (5–29%)
Head titubation	Sometimes (5–29%)
Loss of articulate speech	Sometimes (5–29%)
Oromandibular dystonia	Sometimes (5–29%)
Parkinsonism	Sometimes (5–29%)
Toe walking	Sometimes (5–29%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Distal muscle wasting	Always
Lower limb spasticity	Always
Weakness of outermost muscles	Always
Muscle degeneration	Very often (80–99%)
Muscle weakness	Very often (80–99%)
Uncontrollable movement in upper arms	Very often (80–99%)
Lower-limb joint contracture	Often (30–79%)
Muscle fiber degeneration	Often (30–79%)
Spastic diplegia	Often (30–79%)
Spasticity and rigidity of muscles	Often (30–79%)
Upper-limb joint contracture	Often (30–79%)
Neck flexion weakness	Sometimes (5–29%)
Opisthotonus	Sometimes (5–29%)
Proximal neurogenic muscle weakness	Sometimes (5–29%)
Scoliosis	Sometimes (5–29%)
Spinal muscle degeneration	Not recorded

Abnormality of limbs

Trait	How often it is seen
Absent ankle reflexes	Always
Foot drop	Always
Lower limb muscle weakness	Always
Weakness of the intrinsic hand muscles	Always
Claw hand deformity	Often (30–79%)
Hammertoe	Not recorded
High-arched foot	Not recorded

Abnormality of head or neck

Trait	How often it is seen
Abnormally small head	Sometimes (5–29%)
Retrocollis	Sometimes (5–29%)

Abnormality of the digestive system

Trait	How often it is seen
Gastrostomy tube feeding in infancy	Sometimes (5–29%)
Poor swallowing	Sometimes (5–29%)

Abnormality of the eye

Trait	How often it is seen
Involuntary, rapid, rhythmic eye movements	Sometimes (5–29%)
Supranuclear gaze palsy	Sometimes (5–29%)

Abnormality of the genitourinary system

Trait	How often it is seen
Loss of bladder control	Sometimes (5–29%)

Growth abnormality

Trait	How often it is seen
Wasting syndrome	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 SIGMAR1 and how often each is seen. Find out more at hpo.jax.org.

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