Detection of a major gene predisposing to human T lymphotropic virus type I infection in children among an endemic population of African origin

Human T lymphotropic virus type I (HTLV-I) is a human oncoretrovirus that c auses an adult T cell leukemia/lymphoma and a chronic neuromyelopathy, To i nvestigate whether familial aggregation of HTLV-I infection (as determined by specific seropositive status) could be explained in part by genetic fact ors, we conducted a large genetic epidemiological survey in an HTLV-I-endem ic population of African origin from French Guiana, All of the families in 2 villages were included, representing 83 pedigrees with 1638 subjects, of whom 165 (10.1%) were HTLV-I seropositive. The results of segregation analy sis are consistent with the presence of a dominant major gene predisposing to HTLV-I infection, in addition to the expected familial correlations (mot her-offspring, spouse-spouse) due to the virus transmission routes. Under t his genetic model, similar to 1.5% of the population is predicted to be hig hly predisposed to HTLV-I infection, and almost all seropositive children < 10 years of age are genetic cases, whereas most HTLV-I seropositive adults are sporadic cases.