RESUMO
<p><b>BACKGROUND</b>To study the polymorphism of human cytomegalovirus US28 gene in children and investigate the relationship between the polymorphism and pathogenesis.</p><p><b>METHODS</b>The FQ-PCR was carried out to determine the DNA quantity of clinical isolate and then the segmental PCR and HMA-SSCP were performed to test the mutation of US28 gene. The typical isolates from different diseases were selected to clone and sequence, then the results were analyzed.</p><p><b>RESULTS</b>The nucleic acid mutation is frequent among the sequence of US28, those mutations focus on the two ends of US28, but most of them are sense mutation. The important functional groups of US28 are highly conserved. The amino acid mutation of some isolates resulted in the change of secondary structure, but the phylogenetic tree analysis did not show any clear association between the pathogenesis and the distribution of clinical isolates. The comparison of US28 sequences from AIDS patients with the sequences from children in our study showed that both sequences have their own specific high mutation points.</p><p><b>CONCLUSION</b>There is polymorphism among the HCMV-US28 gene of clinical isolates from children. There observed no clear relationship was between the pathogenesis and the distribution of clinical isolates.</p>