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 brainstem morphology | Very frequent (present in 80%-99% of cases) |
| Alopecia of scalp | Very frequent (present in 80%-99% of cases) |
| Ataxia | Very frequent (present in 80%-99% of cases) |
| Brachycephaly | Very frequent (present in 80%-99% of cases) |
| Cerebellar vermis hypoplasia | Very frequent (present in 80%-99% of cases) |
| Cognitive impairment | Very frequent (present in 80%-99% of cases) |
| Corneal opacity | Very frequent (present in 80%-99% of cases) |
| Hydrocephalus | Very frequent (present in 80%-99% of cases) |
| Impaired pain sensation | Very frequent (present in 80%-99% of cases) |
| Intellectual disability, moderate | Very frequent (present in 80%-99% of cases) |
| Low-set ears | Very frequent (present in 80%-99% of cases) |
| Midface retrusion | Very frequent (present in 80%-99% of cases) |
| Turricephaly | Very frequent (present in 80%-99% of cases) |
| Anteverted nares | Frequent (present in 30%-79% of cases) |
| Hypertelorism | Frequent (present in 30%-79% of cases) |
| Mask-like facies | Frequent (present in 30%-79% of cases) |
| Telecanthus | Frequent (present in 30%-79% of cases) |
| Thin vermilion border | Frequent (present in 30%-79% of cases) |
| Toenail dysplasia | Frequent (present in 30%-79% of cases) |
| Visual impairment | Frequent (present in 30%-79% of cases) |
| Agenesis of cerebellar vermis | - |
| Alopecia | - |
| Bipolar affective disorder | - |
| Fusion of the cerebellar hemispheres | - |
| Growth hormone deficiency | - |
| High palate | - |
| Hyperactivity | - |
| Hyperreflexia | - |
| Hypertonia | - |
| Malar flattening | - |
| Muscular hypotonia | - |
| Opacification of the corneal stroma | - |
| Posteriorly rotated ears | - |
| Seizures | - |
| Self-injurious behavior | - |
| Short nose | - |
| Skull asymmetry | - |
| Smooth philtrum | - |
| Sporadic | - |
| Strabismus | - |
| Wide anterior fontanel | - |
| Wormian bones | - |
The resources below provide information about treatment options for this condition. If you have questions about which treatment is right for you, talk to your healthcare professional.
Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.
Nonprofit support and advocacy groups bring together patients, families, medical professionals, and researchers. These groups often raise awareness, provide support, and develop patient-centered information. Many are the driving force behind research for better treatments and possible cures. They can direct people to research, resources, and services. Many groups also have experts who serve as medical advisors. Visit their website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.
Living with a genetic or rare disease can impact the daily lives of patients and families. These resources can help families navigate various aspects of living with a rare disease.
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.
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