Pelizaeus-Merzbacher disease is divided into classic and severe (connatal) types. Although these two types differ in severity, their symptoms can overlap.Classic Pelizaeus-Merzbacher disease is the more common type. Within the first year of life, those affected with classic Pelizaeus-Merzbacher disease typically experience weak muscle tone (
Severe or connatal Pelizaeus-Merzbacher disease is the more severe of the two types. Symptoms are usually present at birth or develop in the first few weeks of life. Features include nystagmus, problems feeding, a whistling sound when breathing, progressive spasticity leading to joint deformities (
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||
|100% of people have these symptoms|
Involuntary, rapid, rhythmic eye movements
|80%-99% of people have these symptoms|
|Abnormal pyramidal sign||0007256|
Psychiatric disturbances[ more ]
|Cerebral cortical atrophy||
Decrease in size of the outer layer of the brain due to loss of brain cells
Loss of developmental milestones
Mental deterioration in childhood[ more ]
|Failure to thrive in infancy||
Faltering weight in infancy
Weight faltering in infancy[ more ]
Impaired gait[ more ]
Stiff joints[ more ]
Round back[ more ]
Low or weak muscle tone
Premature delivery of affected infants
Preterm delivery[ more ]
|Progressive spastic quadriplegia||0002478|
Abnormal curving of the spine
Signs and symptoms worsen slowly with time
Involuntary muscle stiffness, contraction, or spasm
Loss of eyesight
Poor vision[ more ]
|30%-79% of people have these symptoms|
|Abnormality of the urinary system||
Urinary tract abnormalities
Urinary tract abnormality
Urinary tract anomalies[ more ]
|Abnormality of visual evoked potentials||0000649|
Loss of bowel control
|Delayed speech and language development||
Deficiency of speech development
Delayed language development
Delayed speech acquisition
Delayed speech development
Impaired speech and language development
Impaired speech development
Language development deficit
Late-onset speech development
Poor language development
Speech and language delay
Speech and language difficulties
Speech delay[ more ]
Difficulty articulating speech
Swallowing difficulty[ more ]
|Failure to thrive||
Weight faltering[ more ]
Hearing defect[ more ]
Mental retardation, nonspecific
Mental-retardation[ more ]
Abnormally small skull
Decreased circumference of cranium
Decreased size of skull
Reduced head circumference
Small head circumference[ more ]
|Neurological speech impairment||
Speech impediment[ more ]
|Recurrent respiratory infections||
Frequent respiratory infections
Multiple respiratory infections
respiratory infections, recurrent
Susceptibility to respiratory infections[ more ]
|Reduction of oligodendroglia||0100709|
Decreased body height
Small stature[ more ]
|5%-29% of people have these symptoms|
|1%-4% of people have these symptoms|
Decreased reflex response
Decreased reflexes[ more ]
|Percent of people who have these symptoms is not available through HPO|
Decreased muscle tone
Low muscle tone[ more ]
Onset in first year of life
Onset in infancy[ more ]
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.
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 Krabbe disease, Canavan disease, metachromatic leukodystrophy, Alexander disease, familial SPG, PMLD (see these terms), and cerebral palsy.
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. Submit a new question
There is a history of Pelizaeus-Merzbacher disease in my family. I would like to learn more about this condition, including it's causes, symptoms, treatment and prognosis. See answer
How rare is Pelizaeus-Merzbacher disease? See answer