Hereditary myelopathies.

Hereditary myelopathies comprise a diverse group of disorders whose signs and symptoms include progressive spasticity, limb ataxia without additional cerebellar signs, impaired vibration and positional sensation, and a variable degree of neurogenic weakness, all suggesting spinal cord impairment. Recent progress in the understanding of hereditary myelopathies has revealed that many are systemic processes with widespread axonal degeneration. However, the concept of hereditary myelopathies remains clinically helpful in differentiating hereditary myelopathies from other potentially treatable myelopathies. In this article, hereditary myelopathies are divided into four categories: hereditary spastic paraplegias, motor neuron disorders, spinocerebellar and spastic ataxias, and metabolic disorders, including leukodystrophies.