Pelizaeus-Merzbacher Disease, also known as PMD is a degenerative disease that causes coordination, motor skills, and intellectual functions to progressively deteriorate, basically a central nervous system disorder. Pelizaeus-Merzbacher is inherited from the mother, who is the carrier of the PLP1 mutation, to her male fetus as an X-linked recessive trait. The PLP1 mutation is the mutation in the gene that controls the production of the proteolipid protein-1, which is a myelin protein. The myelin protein is part of the myelin sheath which is the fatty covering that protects and wraps the nerve fibers in the brain. Pelizraeus-Merzbacher disease (PMD) has four types or classifications. The most severe type is Connatal PMD which causes severe neurological problems as well as delayed physical and mental developments. Speech complications or pharyngeal weakness can be found in patients. Classic PMD causes muscle weakness, delays in motor skills, and involuntary eye movements during the first year of life. Complicated Spastic Paraplegia Type 2 (SPG2) causes symptoms not to show up until after the first year of life. Muscle contractions and involuntary movements in the lower limbs can occur. Pure Spastic Paraplegia Type 2 or PureSPG2 cases include those with PMD that do not show neurological problems.
Approximately 1 in 500,000 people are affected with Pelizaeus-Merzbacher Disease. At the present time there is no cure of Pelizaeus-Merzbacher Disease. The course of treatment for PMD is to treat the symptoms of the disease as needed as PMD progresses. Supported care such as antispasticity agents, physical therapy, and orthotics are given as needed. Tracheostomy or feeding tubes may be necessary forms of treatment for some patients.
Genetic testing and MRI’s are two of the most common tests for diagnosing PMD. Nuerology.org states that Brainstem auditory evoked responses (BAERs) can be detected in infants as early as one month old and can be useful for a PMD diagnosis.
The prognosis of Pelizaeus-Merzbacher Disease ranges from good to poor depending on the symptoms and form of the disease. Patients with a mild form of PMD can possibly have a normal life span. The more severe forms have progressive deterioration until an eminent death.
Information on Pelizaeus-Merzbacher Disease can be found at the National Institute of Neurological Disorders and Stroke, the National Organization for Rare Diseases, and The PMD Foundation. Unfortunately even with the world wide web are our fingertips, information on Pelizaeus-Merzbacher is scarce when compare to other diseases. A mere 55,000 results immerge when Google, most of which are clinical papers or medical journals which have terminology that most don’t understand.