HIVdb version 8.4 (last updated 2017-06-16)

NRTI Resistance Comments

(PI · NNRTI · INSTI)
ConditionComment/
Mutation Type
Comment
40FNRTIE40F is a non-polymorphic accessory mutation selected by AZT and d4T. It usually occurs in combination with M41L, L210W and T215Y. In this context it is associated with reduced susceptibility to each of the NRTIs.
41IOtherM41I is usually an artifact resulting from APOBEC3G-mediated hypermutation.
41LNRTIM41L is a TAM that usually occurs with T215Y. In combination, M41L plus T215Y confer intermediate / high-level resistance to AZT and d4T and contribute to reduced ddI, ABC and TDF susceptibility.
44ADNRTIE44D is a relatively non-polymorphic accessory mutation and E44A is a nonpolymorphic accessory mutation. Each usually occurs with multiple TAMs.
62VNRTIA62V is an accessory mutation that often occurs in combination with the multi-NRTI resistance mutations K65R or Q151M. A62V is widespread in subtype A viruses in former Soviet Union countries but A62 is otherwise non-polymorphic.
65ENRTIK65R causes intermediate/high-level resistance to TDF, ddI, ABC and d4T and low/intermediate resistance to 3TC and FTC. K65R increases susceptibility to AZT. K65E is an extremely rare NRTI-selected mutation with markedly reduced replication fitness.
65NNRTIK65R causes intermediate/high-level resistance to TDF, ddI, ABC and d4T and low/intermediate resistance to 3TC and FTC. K65R increases susceptibility to AZT. K65N is a rare mutation with similar but less pronounced effects on NRTI susceptibility than K65R.
65RNRTIK65R causes intermediate/high-level resistance to TDF, ddI, ABC and d4T and low/intermediate resistance to 3TC and FTC. K65R increases susceptibility to AZT.
67DeletionNRTIAmino acid deletions between codons 67 and 70 are rare and usually occur in combination with multiple TAMs, K65R, or the Q151M mutation complex. Deletions at position 67 are more often associated with multiple TAMs. Deletions at positions 69 and 70 are more often associated with K65R or the Q151M mutation complex.
67GESTHNRTID67N is a non-polymorphic TAM associated with low-level resistance to AZT and d4T. When present with other TAMs, it contributes reduced susceptibility to ABC, ddI, and TDF. D67G/E/S/T/H are non-polymorphic NRTI-selected mutations that also generally occur in viruses with multiple TAMs.
67NNRTID67N is a non-polymorphic TAM associated with low-level resistance to AZT and d4T. When present with other TAMs, it contributes reduced susceptibility to ABC, ddI, and TDF.
68DeletionNRTIAmino acid deletions between codons 67 and 70 are rare and usually occur in combination with multiple TAMs, K65R, or the Q151M mutation complex. Deletions at position 67 are more often associated with multiple TAMs. Deletions at positions 69 and 70 are more often associated with K65R or the Q151M mutation complex. Deletions at codon 68 are extremely rare and less well characterized.
68GOtherS68G is a polymorphic mutation that is often selected in combination with K65R. It partially restores the replication defect associated with K65R.
69DeletionNRTIAmino acid deletions between codons 67 and 70 are rare and usually occur in combination with multiple TAMs, K65R, or the Q151M mutation complex. Deletions at position 67 are more often associated with multiple TAMs. Deletions at positions 69 and 70 are more often associated with K65R or the Q151M mutation complex.
69DNRTIT69D is a non-polymorphic mutation that reduces susceptibility to ddI and possibly d4T.
69GNRTIT69G is a rare non-polymorphic mutation that usually occurs in viruses with a deletion at codon 67 and multiple other NRTI-resistance mutations.
69NOtherT69N is a relatively non-polymorphic mutation weakly selected in patients receiving NRTIs. In combination with TAMs, it may contribute minimally reduced susceptibility to ddI, d4T, and AZT.
69SAIEOtherT69S/A/I/E are relatively polymorphic mutations weakly selected in patients receiving NRTIs. Their effects on NRTI susceptibility have not been well studied.
69InsertionNRTIAmino acid insertions between codons 67 and 70 are by convention assigned to codon 69. Together with TAMs, they are associated with high-level resistance to AZT, d4T, ddI, ABC and TDF and intermediate to 3TC and FTC.
70DeletionNRTIAmino acid deletions between codons 67 and 70 are rare and usually occur in combination with multiple TAMs, K65R, or the Q151M mutation complex. Deletions at position 67 are more often associated with multiple TAMs. Deletions at positions 69 and 70 are more often associated with K65R or the Q151M mutation complex.
70EGNRTIK70E/G cause low-level resistance to TDF, ABC, DDI and possibly 3TC and FTC. K70E/G increase susceptibility to AZT.
70QNSTNRTIK70E/G cause low-level resistance to TDF, ABC, DDI and possibly 3TC and FTC. K70E/G increase susceptibility to AZT. K70Q/N/S/T are rare non-polymorphic NRTI-selected mutations that appear to have resistance profiles similar to K70E/G.
70RNRTIK70R causes intermediate resistance to AZT and possibly low-level resistance to D4T, DDI, ABC and TDF.
74VINRTIL74V/I cause high-level resistance to ddI and intermediate resistance to ABC.
75INRTIV75I is a relatively non-polymorphic accessory mutation that often occurs in combination with the multi-NRTI resistance mutation Q151M. When V75I occurs alone its clinical significance is uncertain.
75MNRTIV75M causes intermediate d4T resistance, low-level ddI resistance, and potentially low-level AZT resistance.
75SANRTIV75S/A are non-polymorphic mutations that appear to reduce susceptibility to d4T and ddI.
75TNRTIV75T causes high-level d4T resistance and intermediate ddI resistance.
77LNRTIF77L usually occurs in combination with the multi-NRTI resistance mutation Q151M. When it occurs alone, its clinical significance is uncertain.
115FNRTIY115F causes intermediate resistance to ABC and low-level resistance to TDF.
116YNRTIF116Y usually occurs in combination with the multi-NRTI resistance mutation Q151M.
118IOtherV118I is a polymorphic accessory NRTI-resistance mutation that often occurs in combination with multiple TAMs.
151LNRTIQ151M causes intermediate/high-level resistance to AZT, ddI, d4T and ABC and low-level resistance to TDF, 3TC and FTC. In combination with accessory mutations at positions 62, 75, 77, and 116, Q151M confers high-level resistance to AZT, ddI, d4T and ABC and intermediate resistance to TDF, 3TC and FTC. Q151L is an extremely rare transitional mutation that may precede the emergence of the Q151M.
151MNRTIQ151M causes intermediate/high-level resistance to AZT, ddI, d4T and ABC and low-level resistance to TDF, 3TC and FTC. In combination with accessory mutations at positions 62, 75, 77, and 116, Q151M confers high-level resistance to AZT, ddI, d4T and ABC and intermediate resistance to TDF, 3TC and FTC.
184VINRTIM184V/I cause high-level in vitro resistance to 3TC and FTC and low-level resistance to ddI and ABC. However, M184V/I are not contraindications to continued treatment with 3TC or FTC because they increase susceptibility to AZT, TDF and d4T and are associated with clinically significant reductions in HIV-1 replication.
210WNRTIL210W is a TAM that usually occurs in combination with M41L and T215Y. The combination of M41, L210W and T215Y causes high-level resistance to AZT and d4T and intermediate to high-level resistance to ddI, ABC and TDF.
215FNRTIT215F is a TAM that causes intermediate/high-level resistance to AZT and d4T, low-level resistance to ddI, and potentially low-level resistance to ABC and TDF.
215SCDEIVALNNRTIT215Y/F cause intermediate/high-level resistance to AZT and d4T, low-level resistance to ddI, and potentially low-level resistance to ABC and TDF. T215S/C/D/E/I/V/N/A/L do not reduce NRTI susceptibility but arise from viruses that once contained T215Y/F. The presence of one of these revertant mutations suggests that the patient may have once had a majority virus population with T215Y/F.
215YNRTIT215Y is a TAM that causes intermediate/high-level resistance to AZT and d4T, low-level resistance to ddI, and potentially low-level resistance to ABC and TDF.
219NRNRTIK219N/R are accessory TAMS that usually occur in combination with multiple other TAMs.
219QENRTIK219Q/E are accessory TAMS associated with reduced susceptibility to AZT and possibly d4T.
219WNRTIK219W is an uncommon NRTI-selected mutation.