A multicenter prospective study of the growth and neuropsychological function of 207 boys (mean age 12 years) with hemophilia and seropositive for human immunodeficiency virus type 1 (HIV-1) is reported from the University of Iowa College of Medicine, Iowa City. Head trauma was sustained in 40%, intracranial hemorrhage occurred in 10%, and seizures in 9%. Behavioral disorders in 15% and intracranial infections in 4% of the total were most frequent in the HIV positive group. Neurologic abnormalities, involving cranial nerves (11%), deep tendon reflexes (17%), coordination (25%), muscle strength (23%), and tone (31%), were more common in children of 12 years and older. They were similar in frequency in HIV-seronegative and seropositive subjects, except for deep tendon reflexes and muscle tone and bulk, which were more frequently abnormal in seropositive individuals. Substantial neurological dysfunction could be attributed to hemophilia, but HIV-1 contributes to the neurologic morbidity of hemophiliacs. 
COMMENT. The effect of HIV-1 or its treatment on muscle and peripheral nerve was reflected by non-hemophilia-related reductions in muscle tone and bulk, identified only in HIV-1 seropositive subjects. HIV-1 was also responsible for the majority of behavioral disorders and intracranial infections observed in hemophilic children.
Of multiple MRI abnormalities, including arachnoid cysts, focal lesions, and multifocal white-matter lesions, found in 80 of 310 hemophilic boys, only diffuse cerebral atrophy was associated with HIV infection, and only in subjects with compromised immunologic function . Cerebral atrophy is the most consistent neuroradiological abnormality among children with HIV infection, reported in 85%.