Human cytomegalovirus-encoded alpha -chemokines exhibit high sequence variability in congenitally infected newborns.

Most congenital human cytomegalovirus (HCMV) infections are asymptomatic, but some lead to severe disease. We hypothesized that differences in disease manifestations may be partially explained by differences in viral strains. We recently reported an association between unique long (UL) 144 gene polymorphisms and clinical disease. We now report on the sequence heterogeneity of 2 potential HCMV virulence genes that encode alpha -chemokines: UL146 and UL147. These 2 genes were highly divergent in cultured isolates obtained from 23 newborns with congenital HCMV infection and were difficult to categorize. Unlike our findings for the contiguous UL144 gene, no specific UL146 or UL147 genotype was associated with disease outcome.