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) |
| EEG with focal sharp slow waves | Very frequent (present in 80%-99% of cases) |
| Encephalopathy | Very frequent (present in 80%-99% of cases) |
| Intellectual disability | Very frequent (present in 80%-99% of cases) |
| Abnormality of brainstem morphology | Frequent (present in 30%-79% of cases) |
| Aggressive behavior | Frequent (present in 30%-79% of cases) |
| Atonic seizures | Frequent (present in 30%-79% of cases) |
| Atypical absence seizures | Frequent (present in 30%-79% of cases) |
| Autistic behavior | Frequent (present in 30%-79% of cases) |
| Falls | Frequent (present in 30%-79% of cases) |
| Generalized tonic seizures | Frequent (present in 30%-79% of cases) |
| Generalized tonic-clonic seizures | Frequent (present in 30%-79% of cases) |
| Hyperactivity | Frequent (present in 30%-79% of cases) |
| Mental deterioration | Frequent (present in 30%-79% of cases) |
| Myoclonus | Frequent (present in 30%-79% of cases) |
| Personality disorder | Frequent (present in 30%-79% of cases) |
| Focal seizures | Occasional (present in 5%-29% of cases) |
| Generalized myoclonic seizures | Occasional (present in 5%-29% of cases) |
| Abnormality of the periventricular white matter | - |
| Abnormality of the teeth | - |
| Autosomal recessive inheritance | - |
| Downslanted palpebral fissures | - |
| Dysphagia | - |
| Enlarged cisterna magna | - |
| Epileptic encephalopathy | - |
| Frontotemporal cerebral atrophy | - |
| Gastroesophageal reflux | - |
| Gingival overgrowth | - |
| High forehead | - |
| Hypoplasia of the corpus callosum | - |
| Intellectual disability, progressive | - |
| Intellectual disability, severe | - |
| Low-set ears | - |
| Macrocephaly | - |
| Posteriorly rotated ears | - |
| Progressive | - |
| Ptosis | - |
| Recurrent respiratory infections | - |
| Tented upper lip vermilion | - |
Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a 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.
Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know. Submit a new question
Is there a life expectancy for Lennox-Gastaut syndrome? See answer
