A highly prevalent polymorphism at codon 72 of HIV-1 reverse transcriptase in Argentina prevents hybridization reaction at codon 74 in the LiPA genotyping test.

The aim of this study was to compare the performance of two commercial drug-resistance HIV-1genotyping kits: LiPA (Innogenetics, Belgium) and TruGene (Visible Genetics, Canada). Samples from 103 HIV-1 infected individuals from Argentina were studied. The average correlation between the two methods was 92.81%. More codons could be analysed by TruGene than by LiPA (610/618 and 541/618 codons, respectively). The sequences of the samples and the LiPA probes were aligned showing that a silent mutation at codon 72 (AGA-->AGG) of the HIV-1 reverse transcriptase, which was not recognised by the LiPA probes, was present in 35/36 non-reactive samples for position 74. The overall prevalence of this polymorphism in the population studied was 39.81%. When sequences from different parts of the world were analysed 189/3395 (5.63%) carried the mutation at codon 72, while 23/133 (17.29%) of the sequences from Latin America (excluding Argentina) had this mutation. In both cases, the prevalence of this polymorphism in the Argentinean population was significantly higher. This highlights the importance of carrying out studies on the performance of genotyping kits outside the United States and Europe, especially in areas where non-B HIV-1 subtypes are prevalent.