Traits

Traits linked to GCSH

glycine cleavage system protein H

The Human Phenotype Ontology links 51 traits to GCSH, 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 diffusion weighted cerebral MRI morphology	Always
Absent reflexes	Always
Agitation	Always
Autism spectrum disorder	Always
Coma	Always
Dystonia	Always
EEG with burst suppression	Always
Elevated brain glycine level by MRS	Always
Elevated brain lactate level by MRS	Always
Epilepsy	Always
Exaggerated startle response	Always
Global developmental delay	Always
Hallucinations	Always
Hypsarrhythmia	Always
Impulsivity	Always
Increased reflexes	Always
Infantile spasms	Always
Irritability	Always
Jerking	Always
Lethargy	Always
More active than typical	Always
Multifocal seizures	Always
Myoclonic seizure	Always
Reduced brain N-acetyl aspartate level by MRS	Always
Seizure affecting one half of brain	Always
Thin corpus callosum	Always
Underdevelopment of part of brain called corpus callosum	Always

Laboratory abnormality

Trait	How often it is seen
Elevated blood glycine levels	Always
High blood sugar	Always
Increased CSF glycine concentration	Always
Low blood sugar	Always
High blood sodium levels	Often (30–79%)
Metabolic acidosis	Often (30–79%)

Abnormality of head or neck

Trait	How often it is seen
Development of small head that was not present at birth	Always
Gum enlargement	Always
Long, narrow head	Always
Nasal tip, upturned	Always
Open mouth	Always

Abnormality of the digestive system

Trait	How often it is seen
Decreased liver function	Always
Feeding difficulties	Always
Poor suck	Always

Abnormality of the musculoskeletal system

Trait	How often it is seen
Low muscle tone in trunk	Always
Spasticity and rigidity of muscles	Always
Low muscle tone	Very often (80–99%)

Abnormality of the respiratory system

Trait	How often it is seen
Apnea	Always
Respiratory failure requiring assisted ventilation	Always

Abnormality of blood and blood-forming tissues

Trait	How often it is seen
Low platelet count	Always

Abnormality of limbs

Trait	How often it is seen
Abnormal rhythmic movements of ankle	Always

Abnormality of the cardiovascular system

Trait	How often it is seen
Partial atrioventricular canal defect	Always

Abnormality of the integument

Trait	How often it is seen
Blue discoloration of the skin	Always

Constitutional symptom

Trait	How often it is seen
Hiccup	Always

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

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