The Human Phenotype Ontology (HPO) project provides an ontology of medically relevant phenotypes, disease-phenotype annotations, and the algorithms. Ontology is a set of concepts and categories in a subject area that shows their properties and the relations between them. The HPO is being increasingly adopted as a standard for phenotypic abnormalities by diverse groups such as international rare disease organizations, registries, clinical labs, biomedical resources, and clinical software tools and will thereby contribute toward nascent efforts at global data exchange for identifying disease etiologies (Köhler et al, 2017). AHC is included in the HPO and provides a strategic roadmap of this disease.
| 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 |
