LAUSR

We thank Pinto et al. for their interest in our article on acute intermittent porphyria-related leukoencephalopathy.1 We agree that with the identification of this family, 3 clinical syndromes associated with HMBS mutations are distinguishable. It is exciting that genetic progress reveals such unexpected disease diversity. Pinto et al. implied that the family described could be classified as “complicated hereditary spastic paraplegia”; we disagree, as virtually all leukodystrophies could then be classified as such. The term complicated hereditary spastic paraplegia is commonly reserved for neuronal degenerative disorders predominantly affecting the long fibers of the corticospinal tracts2,3; leukodystrophies are specifically excluded.3