Familial Spastic Paraparesis Syndrome Associated with HTLV-I Infection

HUMAN T-cell lymphotropic virus Type I (HTLV-I) is a retrovirus identified as the etiologic agent of adult T-cell leukemia and lymphoma.1 , 2 More recently, HTLV-I infection has been implicated in the causation of chronic progressive myelopathies, such as tropical spastic paraparesis3 , 4 and HTLV-I—associated myelopathy.5 HTLV-I—associated myelopathy affects patients from southern Japan, which has a temperate climate, whereas tropical spastic paraparesis affects persons from tropical areas. Despite these differences, the two conditions resemble each other,6 prompting some to suggest that they are different names for the same disease.7 HTLV-I has been implicated in the development of these conditions, because affected persons have . . .