The Human Phenotype Ontology (HPO) project provides an ontology of medically relevant phenotypes, disease-phenotype annotations, and algorithms. AHC is included in the HPO and provides a strategic roadmap of this disease.
Ontology is a set of concepts and categories that show their properties and their relationships. The HPO is adopted as a standard for phenotypic abnormalities within international rare disease organizations, registries, clinical labs, biomedical resources, and clinical software tools.
| PHENOTYPIC ASSOCIATIONS | TERM NAME | FREQUENCY |
|---|---|---|
| Growth | Failure to thrive | Frequent |
| Head and neck | Downturned corners of mouth | Occasional |
| Exaggerated cupid’s bow | Occasional | |
| High forehead | Occasional | |
| Eye | Nystagmus | Frequent |
| Occulomotor apraxia | Occasional | |
| Ocular flutter | Occasional | |
| Mydriasis | Frequent | |
| Exotropia | Frequent | |
| Abnormal involuntary eye | Frequent | |
| Cardiovascular | Arrhythmia | Very rare |
| Abnormal T-wave | Occasional | |
| Cardiomyopathy | Very rare | |
| Cardiac conduction abnormality | Occasional | |
| Respiratory System | Respiratory distress | Occasional |
| Apnea | Occasional | |
| Aspiration | Occasional | |
| Digestive System | Gastrointestinal dysmotility | Very frequent |
| Constipation | Frequent | |
| Diarrhea | Frequent | |
| Vomiting | Frequent | |
| Anorexia | Frequent | |
| Abdominal distention | Frequent | |
| Abnormality of the GI tract | Very Frequent | |
| Musculature | ||
| Hypotonia | Occasional | |
| Rigidity | Occasional | |
| Facial hypotonia | Occasional | |
| Limbs | Skewfoot | Occasional |
| Skin, Hair, and Nails | Flushing | Frequent |
| Thin eyebrow | Occasional | |
| Pallor | Frequent | |
| Hyperhidrosis | Occasional | |
| Nervous System | Bulbar signs | Occasional |
| Abnormal pyramidal sign | Occasional | |
| Areflexia | Occasional | |
| Seizure | Frequent | |
| Ataxia | Frequent | |
| Intellectual disability | Frequent | |
| Choreoathetosis | Occasional | |
| Dysarthria | Occasional | |
| Hyperreflexia | Occasional | |
| Dystonia | Frequent | |
| Tremor | Occasional | |
| Episodic hemiplegia | Very frequent | |
| Dysphagia | Frequent | |
| Bilateral tonic-clonic seizure | Occasional | |
| Chorea | Occasional | |
| Status epilepticus | Occasional | |
| Tetraparesis | Frequent | |
| Impulsivity | Occasional | |
| Oral-pharyngeal dysphagia | Frequent | |
| Progressive neurologic deterioration | Occasional | |
| Headache | Occasional | |
| Paroxysmal dyskinesia | Occasional | |
| Delayed speech and language | Frequent | |
| Aggressive behavior | Occasional | |
| Emotional liability | Occasional | |
| Behavioral abnormality | Frequent | |
| Neurodevelopmental delay | Frequent | |
| Abnormal autonomic – nervous system physiology | Frequent | |
| Focal motor seizure | Occasional | |
| Metabolism | Dehydration | Occasional |