Traits

Traits linked to PIGB

phosphatidylinositol glycan anchor biosynthesis class B

The Human Phenotype Ontology links 67 traits to PIGB, by body system: features seen in people with one of the gene's rare conditions.

Abnormality of head or neck

Trait	How often it is seen
Little lower jaw	Often (30–79%)
Big lower jaw	Sometimes (5–29%)
Coarse facial features	Sometimes (5–29%)
Failure of development of more than six teeth	Sometimes (5–29%)
High palate	Sometimes (5–29%)
Long eyebrows	Sometimes (5–29%)
Long eyelashes	Sometimes (5–29%)
Long philtrum	Sometimes (5–29%)
Narrow forehead	Sometimes (5–29%)
Protruding tongue	Sometimes (5–29%)
S-shaped eyes	Sometimes (5–29%)
Smooth philtrum	Sometimes (5–29%)
Tented mouth	Sometimes (5–29%)
Upward slanting of the opening between the eyelids	Sometimes (5–29%)
Wide mouth	Sometimes (5–29%)
Wide nasal bridge	Sometimes (5–29%)
Widow's peak	Sometimes (5–29%)
Broad forehead	Not recorded
Broad head shape	Not recorded
Cleft palate	Not recorded
Cleft upper lip	Not recorded
Full cheeks	Not recorded
Pointed chin	Not recorded
Zygomatic flattening	Not recorded

Abnormality of the nervous system

Trait	How often it is seen
Epilepsy	Always
Global developmental delay	Always
Intellectual disability	Always
Absent reflexes	Sometimes (5–29%)
Decreased reflex response	Sometimes (5–29%)
More grooves in brain	Sometimes (5–29%)
Underdevelopment of part of brain called corpus callosum	Sometimes (5–29%)
Ventriculomegaly	Sometimes (5–29%)
Abnormal cerebral white matter morphology	Not recorded
Nerve damage causing decreased feeling and movement	Not recorded
Peripheral axonal neuropathy	Not recorded

Abnormality of the eye

Trait	How often it is seen
Wide-set eyes	Always
Abnormally small eyeball	Sometimes (5–29%)
Bulging eye	Sometimes (5–29%)
Iris degeneration	Sometimes (5–29%)
Optic atrophy	Sometimes (5–29%)
Abnormal visual fixation	Not recorded
Drooping upper eyelid	Not recorded
Optic disc pallor	Not recorded
Visual impairment	Not recorded

Abnormality of limbs

Trait	How often it is seen
Broad thumb	Sometimes (5–29%)
Finger-like thumb	Sometimes (5–29%)
Acetabular dysplasia	Not recorded
Club feet	Not recorded
Short outermost finger bone	Not recorded
Shortened long bone of hand	Not recorded
Tapered finger	Not recorded

Abnormality of the ear

Trait	How often it is seen
Hearing impairment	Often (30–79%)
Overfolded ears	Often (30–79%)
Uplifted earlobe	Often (30–79%)
Ears rotated toward back of head	Sometimes (5–29%)
Low-set ears	Sometimes (5–29%)
Mixed hearing impairment	Sometimes (5–29%)
Abnormally shaped ears	Not recorded

Growth abnormality

Trait	How often it is seen
Short stature	Always
Faltering weight	Not recorded
Growth delay	Not recorded

Abnormality of the musculoskeletal system

Trait	How often it is seen
Generalized decreased muscle tone	Very often (80–99%)
Funnel chest	Sometimes (5–29%)

Laboratory abnormality

Trait	How often it is seen
Elevated alkaline phosphatase	Very often (80–99%)
Increased urine alpha-ketoglutarate concentration	Sometimes (5–29%)

Abnormality of the digestive system

Trait	How often it is seen
Feeding difficulties	Not recorded

Abnormality of the integument

Trait	How often it is seen
Small nail	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 PIGB and how often each is seen. Find out more at hpo.jax.org.

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