Signs and symptoms of the later-onset forms are extremely variable but may include muscle weakness and rigidity; walking difficulties; vision loss; intellectual regression; and/or seizures.
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|
|Abnormal thumb morphology||
Abnormality of the thumb
Abnormality of the thumbs
Thumb deformity[ more ]
|Aplasia/Hypoplasia of the abdominal wall musculature||
Absent/small abdominal wall muscles
Absent/underdeveloped abdominal wall muscles[ more ]
Poor feeding[ more ]
|Global developmental delay||0001263|
|Sensorineural hearing impairment||0000407|
Damage to nerves that sense feeling
Involuntary muscle stiffness, contraction, or spasm
Loss of eyesight
Poor vision[ more ]
|30%-79% of people have these symptoms|
Impaired gait[ more ]
|Generalized myoclonic seizures||0002123|
Paralysis or weakness of one side of body
|Recurrent respiratory infections||
Frequent respiratory infections
Multiple respiratory infections
respiratory infections, recurrent
Susceptibility to respiratory infections[ more ]
|5%-29% of people have these symptoms|
|Percent of people who have these symptoms is not available through HPO|
|Abnormal flash visual evoked potentials||0007928|
|Decreased nerve conduction velocity||0000762|
Loss of developmental milestones
Mental deterioration in childhood[ more ]
|Diffuse cerebral atrophy||0002506|
|Failure to thrive||
Weight faltering[ more ]
Hearing defect[ more ]
Too much cerebrospinal fluid in the brain
|Hyperactive deep tendon reflexes||0006801|
Progressive degeneration of movement
Low or weak muscle tone
Ongoing loss of nerve cells
Involuntary, rapid, rhythmic eye movements
Increased body temperature, episodic
Intermittent fever[ more ]
Nerve damage causing decreased feeling and movement
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.
Related diseases are conditions that have similar signs and symptoms. A health care provider may consider these conditions in the table below when making a diagnosis. Please note that the table may not include all the possible conditions related to this disease.
Conditions with similar signs and symptoms from Orphanet
Differential diagnosis includes metachromatic leukodystrophy, GM1 gangliosidosis, GM2 gangliosidosis, Canavan disease, encephalopathy due to prosaposin deficiency, X-linked adrenoleukodystrophy, Pelizaeus-Merzbacher disease and Alexander disease (see these terms).
Visit the Orphanet disease page for more information.
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.
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.
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.