This disorder belongs to a group of neurodegenerative disorders called leukodystrophies in which there is a deterioration of the nerve covering known as myelin. It is also a member of a family of hereditary, progressive neurological conditions in which there is stiffness primarily of the legs called spastic paraplegia.
Like many neurological conditions, age of onset is variable but it is often diagnosed when children begin to walk. They may appear to be clumsy and stumble frequently. Involuntary to-and-fro eye movements (nystagmus) are often seen in childhood as well. Later the optic nerve has evident deterioration and vision is often severely reduced. Speech is often slurred (dysarthria). Unsteadiness and balance problems soon become evident and sometimes there is a tremor in the arms. Movement becomes more difficult as the neurological deterioration progresses and by the second or third decade of life assistive devices such as crutches and wheelchairs are required.
Mental functioning can be normal in some individuals while others are mentally retarded.
This is an X-linked disorder which is seen almost entirely in males. A few females who carry the gene can have mild symptoms such as tremors in the arms. Males who carry the causative mutation cannot have affected children but all their daughters will be carriers of the mutation and each of their sons have a 50% risk of inheriting the spastic paraplegia 2.
Neurologists, and especially pediatric neurologists, are most likely to make this diagnosis. There is some variation in the rate of neurological deterioration but life expectancy is decreased for all. Some individuals succumb to their illness within the first month of life but this is rare and many live until the fourth decade of life.
There is no known treatment for the neurological symptoms but physical therapy and mobility devices such as crutches and wheel chairs are helpful.
Spastic paraplegia 2 is similar to another disorder, Pelizaeus-Merzbacher disease, which, however is more severe.