Less common features, include:
Age at time of symptom onset varies from infancy to early adulthood, with onset in infancy to adolescence being most common. Learning disability may begin in childhood. Most people experience a decline in intellectual ability and an increase in muscle weakness and nerve abnormalities over time. As the condition progresses, some people require wheelchair assistance (often 10 to 20 years after symptom onset).
This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.
|Medical Terms||Other Names||
|80%-99% of people have these symptoms|
|Aplasia/Hypoplasia of the
|Cerebral cortical atrophy||
Decrease in size of the outer layer of the brain due to loss of brain cells
Difficulty articulating speech
Impaired gait[ more ]
Mental retardation, nonspecific
Mental-retardation[ more ]
Cognitive decline, progressive
Progressive cognitive decline[ more ]
Involuntary, rapid, rhythmic eye movements
|Saccadic smooth pursuit||0001152|
|5%-29% of people have these symptoms|
|Reduced tendon reflexes||0001315|
|Percent of people who have these symptoms is not available through HPO|
|Abnormality of the periventricular white matter||0002518|
Symptoms begin in adulthood
|Agenesis of corpus callosum||0001274|
Abnormal rhythmic movements of ankle
Symptoms begin in childhood
|Decreased number of peripheral myelinated nerve fibers||0003380|
|Degeneration of the lateral corticospinal tracts||0002314|
|Distal peripheral sensory neuropathy||0007067|
Swallowing difficulty[ more ]
|Hypoplasia of the corpus callosum||
Underdevelopment of part of brain called corpus callosum
|Impaired vibration sensation in the lower limbs||
Decreased lower limb vibratory sense
Decreased vibratory sense in lower limbs
Decreased vibratory sense in the lower extremities
Decreased vibratory sense in the lower limbs
Diminished vibratory sensation in the legs[ more ]
|Lower limb muscle weakness||
Lower extremity weakness
Lower limb weakness
Muscle weakness in lower limbs[ more ]
|Lower limb spasticity||0002061|
Having too much body fat
Worsens with time
Damage to nerves that sense feeling
|Specific learning disability||0001328|
|Thenar muscle atrophy||0003393|
Walking on tiptoes
|Urinary bladder sphincter dysfunction||0002839|
Loss of bladder control
Loss of eyesight
Poor vision[ more ]
If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.
If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.
You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.
Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.
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
What is this exactly and how does it effect someone? See answer