Traits

Traits linked to PIGA

phosphatidylinositol glycan anchor biosynthesis class A

The Human Phenotype Ontology links 266 traits to PIGA, 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
Abnormal cerebral white matter morphology	Always
Absent septum pellucidum	Always
Absent speech development	Always
Absent/small cerebral white matter	Always
Aplasia/Hypoplasia of the corpus callosum	Always
Arrhinencephaly	Always
Autism	Always
Babinski sign	Always
Brisk reflexes	Always
Cerebral white matter hypoplasia	Always
CNS hypomyelination	Always
Decrease in size of the outer layer of the brain due to loss of brain cells	Always
Degeneration of cerebellum	Always
Degeneration of cerebrum	Always
Diffuse leukoencephalopathy	Always
Dystonia	Always
EEG with burst suppression	Always
EEG with generalized polyspikes	Always
Encephalopathy	Always
Epilepsy	Always
Epileptic encephalopathy	Always
Exaggerated startle response	Always
Febrile seizure (within the age range of 3 months to 6 years)	Always
Focal clonic seizure	Always
Focal seizure with eyelid myoclonia	Always
Generalized myoclonic seizure	Always
Generalized tonic seizure	Always
Generalized-onset seizure	Always
Gliosis	Always
Global developmental delay	Always
Grand mal seizures	Always
Grasp reflex	Always
Head titubation	Always
Hypsarrhythmia	Always
Inability to walk	Always
Increased reflexes	Always
Instability or lack of coordination of central trunk muscles	Always
IQ between 34 and 49	Always
IQ less than 20	Always
Jerking	Always
Loss of brain cells	Always
Loss of developmental milestones	Always
Motor delay	Always
Neuronal loss in the cerebral cortex	Always
Paralysis of all four limbs	Always
Poor eye contact	Always
Postural tremor	Always
Profound global developmental delay	Always
Repeated seizures without recovery between them	Always
Small cerebellum	Always
Underdevelopment of part of brain called corpus callosum	Always
Ventriculomegaly	Always
Widened subarachnoid space	Always
Cognitive impairment	Very often (80–99%)
Infantile spasms	Very often (80–99%)
Multifocal epileptiform discharges	Very often (80–99%)
Neurodevelopmental delay	Very often (80–99%)
Abnormality of the nervous system	Often (30–79%)
Bilateral tonic-clonic seizure with focal onset	Often (30–79%)
Focal emotional seizure with laughing	Often (30–79%)
Focal hemiclonic seizure	Often (30–79%)
Focal impaired awareness seizure	Often (30–79%)
Headache	Often (30–79%)
Lateral ventricle dilatation	Often (30–79%)
Myoclonic seizure	Often (30–79%)
Olfactory lobe absence	Often (30–79%)
Abnormal corpus callosum morphology	Sometimes (5–29%)
Ataxia	Sometimes (5–29%)
Delayed myelination	Sometimes (5–29%)
Epileptic spasm	Sometimes (5–29%)
Lethargy	Sometimes (5–29%)
Abnormal pons morphology	Not recorded

Abnormality of head or neck

Trait	How often it is seen
Abnormality of the area between the eyebrows	Always
Abnormality of the brow of the face	Always
Abnormality of the face	Always
Abnormality of the philtrum	Always
Absence of adult teeth	Always
Asymmetry of the posterior head	Always
Broad forehead	Always
Broad head shape	Always
Broad opening between the eyelids	Always
Coarse facial features	Always
Decreased facial expression	Always
Decreased size of tooth	Always
Decreased volume of lip	Always
Delayed eruption of teeth	Always
Development of small head that was not present at birth	Always
Facial asymmetry	Always
Failure of development of all teeth	Always
Flat back of skull	Always
High frontal hairline	Always
High, narrow palate	Always
Increased size of gum ridge	Always
Redundant neck skin	Always
Round face	Always
Short opening between the eyelids	Always
Thickened skin folds of neck	Always
Widely spaced teeth	Always
Abnormally small head	Often (30–79%)
Depressed nasal bridge	Often (30–79%)
Downturned corners of mouth	Often (30–79%)
Gum enlargement	Often (30–79%)
High palate	Often (30–79%)
Metopic synostosis	Often (30–79%)
Narrow mouth	Often (30–79%)
Nasal tip, upturned	Often (30–79%)
Prominent back of the head	Often (30–79%)
Short neck	Often (30–79%)
Upward slanting of the opening between the eyelids	Often (30–79%)
Wide fontanelles	Often (30–79%)
Yellowing of the whites of the eyes	Often (30–79%)
Zygomatic flattening	Often (30–79%)
Pierre-Robin sequence	Sometimes (5–29%)
Big calvaria	Not recorded
Increased head circumference	Not recorded
Little lower jaw	Not recorded
Triangular mouth	Not recorded

Laboratory abnormality

Trait	How often it is seen
Abnormal circulating iron concentration	Always
Abnormal liver iron concentration	Always
Decreased circulating hepcidin concentration	Always
Elevated circulating iron concentration	Always
Elevated serum ferritin	Always
Elevated transferrin saturation	Always
Fatty infiltration of liver	Always
Fluid retention	Always
Increased CSF glutamate concentration	Always
Increased iron concentration in liver	Always
Elevated alkaline phosphatase	Very often (80–99%)
Hemoglobin in urine	Very often (80–99%)
Decreased circulating haptoglobin concentration	Often (30–79%)
Decreased circulating iron concentration	Often (30–79%)
Hemosiderinuria	Often (30–79%)
Increased blood urea nitrogen	Often (30–79%)
Increased circulating lactate dehydrogenase concentration	Often (30–79%)
Microvesicular hepatic steatosis	Often (30–79%)
Unconjugated hyperbilirubinemia	Often (30–79%)
High urine protein levels	Sometimes (5–29%)
Glucose in urine	Rarely (1–4%)
Renal Fanconi syndrome	Rarely (1–4%)
Hydrops fetalis	Not recorded
Paroxysmal nocturnal hemoglobinuria	Not recorded

Abnormality of the musculoskeletal system

Trait	How often it is seen
Abnormal shape of joints	Always
Diffuse skeletal muscle wasting	Always
Flexed joint that cannot be straightened	Always
Involuntary muscle stiffness, contraction, or spasm	Always
Limb contractures	Always
Low muscle tone	Always
Low muscle tone in trunk	Always
Muscle degeneration	Always
Opisthotonus	Always
Permanent flexion of the finger or toe	Always
Poor head control	Always
Rigidity	Always
Scoliosis	Always
Spastic tetraplegia	Always
Thin bony cortex	Always
Functional motor deficit	Very often (80–99%)
Small chest	Often (30–79%)
Spasticity and rigidity of muscles	Sometimes (5–29%)
Lower limb spasticity	Not recorded
Uncontrollable movement in upper arms	Not recorded

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Abnormal erythrocyte enzyme concentration or activity	Always
Low platelet count	Always
Stomatocytosis	Always
Hemolytic anemia	Very often (80–99%)
Low number of red blood cells or hemoglobin	Very often (80–99%)
Blood clot in a deep vein	Often (30–79%)
Blood clot in vein	Often (30–79%)
Increased immature red blood cells	Often (30–79%)
Thromboembolism	Often (30–79%)
Blood clot in artery	Sometimes (5–29%)
Decreased blood leukocyte number	Sometimes (5–29%)
Erythroid hyperplasia	Sometimes (5–29%)
Low blood cell count	Sometimes (5–29%)
Mesenteric venous thrombosis	Sometimes (5–29%)

Abnormality of the cardiovascular system

Trait	How often it is seen
Enlarged liver and spleen	Always
Heart stops beating	Always
Increased spleen size	Always
Left ventricular hypertrophy	Always
Right ventricular hypertrophy	Always
Ventricular arrhythmia	Always
An opening in the wall separating the top two chambers of the heart	Often (30–79%)
Patent ductus arteriosus	Often (30–79%)
Aortopulmonary collateral arteries	Sometimes (5–29%)
Blood clot in artery of lung	Sometimes (5–29%)
Budd-Chiari syndrome	Sometimes (5–29%)
Heart attack	Sometimes (5–29%)
High blood pressure	Sometimes (5–29%)
Stroke	Sometimes (5–29%)

Abnormality of the digestive system

Trait	How often it is seen
Abdominal bloating	Always
Accumulation of fluid in the abdomen	Always
Enlarged liver	Always
Liver failure	Always
Micronodular cirrhosis	Always
Starry sky appearance on hepatic sonography	Always
Intermittent abdominal pain	Often (30–79%)
Jaundice	Sometimes (5–29%)
Painful swallowing	Sometimes (5–29%)
Scar tissue replaces healthy tissue in the liver	Sometimes (5–29%)
Esophageal spasms	Rarely (1–4%)
Poor swallowing	Rarely (1–4%)

Abnormality of the eye

Trait	How often it is seen
Abnormal macular morphology	Always
Abnormal visual fixation	Always
Abnormality of eye movement	Always
Breakdown of light-sensitive cells in back of eye	Always
Cerebral visual impairment	Always
Close sighted	Always
Drooping of both upper eyelids	Always
Moderate visual impairment	Always
Optic disc pallor	Always
Wide-set eyes	Always
Visual impairment	Sometimes (5–29%)

Abnormality of the genitourinary system

Trait	How often it is seen
Hydronephrosis	Always
Testicular degeneration	Always
Vesicoureteral reflux	Very often (80–99%)
Chronic kidney disease	Often (30–79%)
Duplicated collecting system	Often (30–79%)
Acute kidney injury	Sometimes (5–29%)
Difficulty getting a full erection	Sometimes (5–29%)
Hypospadias	Sometimes (5–29%)
Renal failure	Sometimes (5–29%)
Undescended testes	Sometimes (5–29%)
Short penis	Not recorded

Abnormality of limbs

Trait	How often it is seen
Abnormal feet structure	Always
Deep palm line	Always
Short finger	Always
Tapered finger	Always
Broad palm	Often (30–79%)
Elbow flexion contracture	Often (30–79%)
Hip contracture	Often (30–79%)
Inability to straighten knee	Often (30–79%)
Lower limb hypertonia	Sometimes (5–29%)

Abnormality of the integument

Trait	How often it is seen
Frontal upsweep of hair	Always
Paleness	Always
Papule	Always
Abnormal skin structure	Often (30–79%)
Ichthyosis	Often (30–79%)
Small nail	Often (30–79%)
Abnormal skin pigmentation	Not recorded

Abnormality of the immune system

Trait	How often it is seen
Acute aspiration pneumonia	Always
Aspiration pneumonia	Always
Pneumonia	Always
Psoriasiform dermatitis	Always
Seborrheic dermatitis	Often (30–79%)

Abnormality of the respiratory system

Trait	How often it is seen
Apnea	Always
Aspiration	Always
Respiratory tract infection	Always
Breathing difficulty	Often (30–79%)
Respiratory failure	Often (30–79%)

Growth abnormality

Trait	How often it is seen
Birth weight > 90th percentile	Always
Short stature	Always
Faltering weight	Sometimes (5–29%)
General overgrowth	Sometimes (5–29%)
Birth length greater than 97th percentile	Not recorded

Abnormality of prenatal development or birth

Trait	How often it is seen
High levels of amniotic fluid	Very often (80–99%)
Bilateral fetal pyelectasis	Often (30–79%)
Feet or buttocks of fetus positioned near opening of uterus	Often (30–79%)
Fetal distress	Often (30–79%)

Abnormality of the ear

Trait	How often it is seen
Hearing impairment	Always
Uplifted earlobe	Always
Overfolded ears	Often (30–79%)

Constitutional symptom

Trait	How often it is seen
Lack of energy and strength	Very often (80–99%)
Chest pain	Often (30–79%)
Erythromelalgia	Often (30–79%)

Abnormal cellular phenotype

Trait	How often it is seen
Abnormality of the mitochondrion	Always

Abnormality of the endocrine system

Trait	How often it is seen
Early onset of puberty	Rarely (1–4%)

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 PIGA and how often each is seen. Find out more at hpo.jax.org.

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