Traits

Traits linked to PGAP1

post-GPI attachment to proteins inositol deacylase 1

The Human Phenotype Ontology links 66 traits to PGAP1, 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
Babinski sign	Always
Degeneration of cerebrum	Always
Delayed ability to roll over	Always
Delayed ability to sit	Always
Delayed ability to walk	Always
Delayed CNS myelination	Always
Delayed speech and language development	Always
Disorder of involuntary muscle movements	Always
Global developmental delay	Always
Increased reflexes	Always
Intellectual disability, severe	Always
IQ between 34 and 49	Always
Motor delay	Always
Repetitive movements	Always
Underdevelopment of part of brain called corpus callosum	Always
Abnormal gait	Often (30–79%)
Abnormal myelination	Often (30–79%)
Abnormality of movement	Often (30–79%)
Absent speech development	Often (30–79%)
Agenesis of corpus callosum	Often (30–79%)
Aplasia/Hypoplasia of the cerebellar vermis	Often (30–79%)
Brief seizures with staring spells	Often (30–79%)
Cerebellar vermis hypoplasia	Often (30–79%)
Decrease in size of the outer layer of the brain due to loss of brain cells	Often (30–79%)
Delayed ability to crawl	Often (30–79%)
Enlarged sylvian cistern	Often (30–79%)
Grand mal seizures	Often (30–79%)
Inappropriate laughter	Often (30–79%)
Intellectual disability	Often (30–79%)
Intellectual disability, mild	Often (30–79%)
Limb tremor	Often (30–79%)

Abnormality of head or neck

Trait	How often it is seen
Abnormal dentition	Always
Depressed nasal bridge	Always
Highly arched eyebrow	Always
Short neck	Always
Thin dental enamel	Always
Upward slanting of the opening between the eyelids	Always
Wide mouth	Always
Abnormally small head	Often (30–79%)
Bifid uvula	Often (30–79%)
Low frontal hairline	Often (30–79%)
Low hairline at back of neck	Often (30–79%)

Abnormality of the musculoskeletal system

Trait	How often it is seen
Involuntary muscle stiffness, contraction, or spasm	Always
Low muscle tone, in neonatal onset	Always
Diffuse skeletal muscle wasting	Often (30–79%)
Low muscle tone	Often (30–79%)
Low muscle tone in trunk	Often (30–79%)
Lower limb spasticity	Often (30–79%)
Muscle degeneration	Often (30–79%)
Progressive spastic paraplegia	Often (30–79%)
Spastic walk	Often (30–79%)
Spasticity and rigidity of muscles	Often (30–79%)

Abnormality of the eye

Trait	How often it is seen
Breakdown of light-sensitive cells in back of eye	Always
Cerebral visual impairment	Always
Deeply set eye	Always
Divergence nystagmus	Always
Involuntary, rapid, rhythmic eye movements	Always
Congenital nystagmus	Often (30–79%)

Abnormality of the cardiovascular system

Trait	How often it is seen
Narrowing of pulmonic valve	Often (30–79%)
Secundum atrial septal defect	Often (30–79%)

Abnormality of the digestive system

Trait	How often it is seen
Feeding difficulties	Always
Gastrostomy tube feeding in infancy	Always

Abnormality of the ear

Trait	How often it is seen
Large ears	Always
Prominent antihelix	Always

Growth abnormality

Trait	How often it is seen
Faltering weight	Often (30–79%)
Short stature	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 PGAP1 and how often each is seen. Find out more at hpo.jax.org.

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