Approach Considerations
No specific treatment for Pelizaeus-Merzbacher disease is known. Medical therapy is limited to supportive care, such as the use of physical therapy, orthotics, and antispasticity agents, including intrathecal baclofen. Regular physical medicine or orthopedic evaluations, physical therapy, and careful attention to posture and seating can help to minimize the development of joint contractures, dislocations, and kyphoscoliosis.
Patients who are severely affected (ie, those who have connatal Pelizaeus-Merzbacher disease) need special attention directed to airway protection and may need anticonvulsant therapy. Developmental assessment is important to maximize cognitive achievement and to assist in proper educational program assignment.
Consultations
Consultation with a geneticist and a genetic counselor is essential for parents of an affected child to educate them about Pelizaeus-Merzbacher disease and the risks to future offspring; consultation may also be critical for establishing and confirming the diagnosis. Confirmation of the disease is likely to have implications for more distant relatives and for the immediate family. Prenatal testing and preimplantation genetic testing are possible and should be offered when appropriate. Identification of a causative mutation would be essential before prenatal testing could be performed. Preimplantation genetic diagnosis is possible when a mutation is known.
Neonates with the connatal form of Pelizaeus-Merzbacher disease should be evaluated by a pulmonologist and perhaps by a neonatal swallowing specialist to evaluate airway safety and swallowing safety, respectively. Feeding tube placement may be necessary.
Regular consultation with a physiatrist or orthopedist and therapy team should be arranged. As the child grows, the physiatrist can help to optimize the patient’s mobility and strengthening and maximize the patient’s capabilities. The use orthotics, custom seating and cushions, and other aids is important for minimizing the development of joint dislocations and kyphoscoliosis. For severe contractures or scoliosis, orthopedic consultation may be beneficial.
Communication therapy, including training in use of communication devices, is often valuable. In addition, a pediatric developmental specialist should be consulted to optimize the child's educational program and to maximize the patient’s functional and learning capabilities.
Medical Care
Pharmacologic therapy
When indicated, antiepileptic medications should be used. Antispasticity medications, such as baclofen, tizanidine, or benzodiazepines, may be beneficial.
Constipation is a common complication and may require the use of mild laxatives, such as senna, fiber supplements, or osmotic agents, such as polyethylene glycol 3350 (MiraLAX, Enemeez).
Surgical Care
Tracheostomy may be needed during infancy if stridor impairs respiratory function. Feeding tube placement may be needed if oral feeding is inadequate to maintain weight or sustain normal growth in a child with Pelizaeus-Merzbacher disease, or if oral feeding poses a significant risk of aspiration.
Some patients with severe spasticity, especially children, may benefit from intrathecal baclofen, as well as from surgical release of contractures and other orthopedic procedures, including the use of spinal rods to correct severe scoliosis.
Diet
Dietary adjustments can have a benefical impact on the pathophysiology of the disease. It has been evident that a diet high in healthy cholesterol, suh as Ketogenic diet, can prolong the life span of oligodendrocytes and the axonal caliber. The ketones produced from this diet can cross the blood brain barrier and provide the essential building blocks for CNS lipid synthesis.
Activity
Within their capabilities, patients should be encouraged to be active for their physical and emotional well-being. A physiatrist or physical therapist can be helpful in providing guidelines for a specific child. Aquatic therapy can be a helpful exercise to maintain leg strength, as well as an enjoyable form of recreation.
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T2-weighted magnetic resonance imaging (MRI) scan of a child aged 10 months with duplication of the proteolipid protein (PLP) gene; note the high-intensity signal throughout the cerebral white matter.
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T2-weighted magnetic resonance imaging (MRI) scan of a man aged 41 years with duplication of the proteolipid protein (PLP) gene; note the increased white matter signal, as well as diffuse atrophy.
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T2-weighted magnetic resonance imaging (MRI) scan of a man aged 20 years with connatal Pelizaeus-Merzbacher disease due to a Pro14Leu mutation; note the severe reduction in white matter volume, as well as the increased white matter signal.
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T2-weighted magnetic resonance imaging (MRI) scan of a boy aged 17 years with null mutation of the proteolipid protein (PLP) gene; note the more subtle increase in signal intensity relative to that seen in the previous images, and observe that the volume of white matter is normal.
