The Human Phenotype Ontology (HPO) provides the following list of features that have been reported in people with this condition. Much of the information in the HPO comes from Orphanet, a European rare disease database. If available, the list includes a rough estimate of how common a feature is (its frequency). Frequencies are based on a specific study and may not be representative of all studies. You can use the MedlinePlus Medical Dictionary for definitions of the terms below.
| Signs and Symptoms | Approximate number of patients (when available) |
| Abnormality of the metacarpal bones | 90% |
| Aplasia/Hypoplasia of the cerebellum | 90% |
| Apnea | 90% |
| Bifid tongue | 90% |
| Cognitive impairment | 90% |
| Foot polydactyly | 90% |
| Hand polydactyly | 90% |
| Incoordination | 90% |
| Muscular hypotonia | 90% |
| Oculomotor apraxia | 90% |
| Abnormality of the hypothalamus-pituitary axis | 50% |
| Cleft upper lip | 50% |
| Cryptorchidism | 50% |
| Gait disturbance | 50% |
| Long face | 50% |
| Narrow forehead | 50% |
| Nystagmus | 50% |
| Aganglionic megacolon | 7.5% |
| Anteverted nares | 7.5% |
| Encephalocele | 7.5% |
| Hernia of the abdominal wall | 7.5% |
| Highly arched eyebrow | 7.5% |
| Iris coloboma | 7.5% |
| Low-set, posteriorly rotated ears | 7.5% |
| Prominent nasal bridge | 7.5% |
| Ptosis | 7.5% |
| Seizures | 7.5% |
| Strabismus | 7.5% |
| Tremor | 7.5% |
These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.
