Clinical Reasoning: A Young Man With Subacute Onset of Spastic Paraparesis.

Leukodystrophies are a group of rare, neurodegenerative disorders, usually presenting in infancy with of a variable combination of cognitive, motor and coordination impairment. Adult-onset cases are even more rare, often representing a diagnostic challenge even for experienced neurologists. Here, we present a case of 44-year-old man with subacute and rapidly progressive spastic paraplegia, whose brain MRI revealed white matter abnormalities compatible with a diagnosis of leukodystrophy. We discuss how to apply a simplified diagnostic algorithm to distinguish acquired leukoencephalopathies from leukodystrophies, and how to delve in the maze of the genetic testing for white matter diseases. In our patient, we reached the diagnosis of a treatable disorder, whose early recognition is essential in order to prevent severe neurological deterioration.