Pelizaeus–Merzbacher disease

The Pelizaeus- Merzbacher disease is a rare congenital disorder of the central nervous system. In this disease from the group of leukodystrophies occurs a disturbance of myelination, by a variety of symptoms may be caused. The disease is named after the Erstbeschreibern Friedrich Christoph Pelizaeus Merzbacher and Ludwig.

Genetics

The Pelizaeus- Merzbacher disease is based on a mutation of the proteolipid protein ( PLP) -encoding gene on the X chromosome ( Xq22 ), which leads to a failure or uselessness of the PLP- production and subsequently to an incorrect composition of the myelin sheaths, the necessary for normal function of the nerve fibers. The inheritance of Pelizaeus- Merzbacher disease is X-linked recessive, which is why only boys and men are usually affected. The observed genetic changes in the disease of the PLP gene are diverse: in addition to deletions and duplications of the PLP gene have been described. The disease is counted in the disease group of hereditary spastic paraplegia or spastic paraplegia. There she is called SPG2 ( spastic paraplegia gen 2 ).

Symptoms

The cardinal symptoms of Pelizaeus- Merzbacher disease is a delay in the normal mental and motor development with uncontrollable, rhythmic movements of the eyes ( nystagmus), paralysis of the muscles ( which can occur in both spastic and flaccid paralysis with loss of tone particularly the core muscles ) and a state - and unsteadiness of gait (ataxia). The disease usually begins in the infant or childhood, but can also manifest only in adulthood.

Related diseases

Diseases similar to the Pelizaeus -Merzbacher disease, but are inherited as autosomal recessive, are:

• Pelizaeus- Merzbacher like disease ( PMLD ) 1: caused by mutations in connexin 47 ( GJA12 ) gene on chromosome 1q41
• Pelizaeus- Merzbacher like disease ( PMLD ) 2

A disease similar to that of Pelizaeus -Merzbacher disease, but is inherited as an autosomal dominant trait and its onset is in adulthood, is the

• Autosomal dominant leukodystrophy ( ADLD ).

Diagnostics

Neurological examination and medical history can give first suspicions. However, Biochemical markers for the disease does not exist. Magnetic resonance imaging of the brain occupied disorders of marrow maturation ( myelination ) of which are not specific to the Pelizaeus -Merzbacher disease. A differentiation from demyelinating diseases can be necessary with the help of magnetic resonance spectroscopy. Proving is the molecular genetic detection of a mutation of the PLP gene on the X chromosome ( Xq22 ). A prenatal diagnosis is possible.

Treatment

The Pelizaeus -Merzbacher disease is not the cause of treatable. Supportive care, including emotional support of family members is recommended as needed. A physiotherapy and occupational therapy aims to improve the quality of life of affected children.

Forecast

The severity of the disease varies considerably among others, depending on the nature of the PLP mutation, ranging from mild gradients at which develops in adulthood manifesting disease to severe disease courses starting in infancy and fatal even in childhood.