# POSITION	AA	CATEGORY	SCORE	COMMENT
41	L	NRTI	Yes	M41L usually occurs with T215Y. Together these mutations confer intermediate-to-high level resistance to AZT and d4T and a lower level of resistance to ddI, ABC, and TDF.
41	NOT L	NRTI		M41L usually occurs with T215Y. Together these mutations confer intermediate-to-high level resistance to AZT and d4T and a lower level of resistance to ddI, ABC, and TDF. $listMutsIn{41(NOT L)} is a highly unusual mutation at this position.
44	AD	NRTI	Yes	E44A/D occur in patients receiving multiple NRTIs. E44D causes low-level resistance to 3TC and probably to each of the other NRTIs when present with V118I or one or more TAMs.
44	NOT AD	Other		None
62	V	NRTI	Yes	A62V is associated with multinucleoside resistance caused by Q151M; its effect in the absence of Q151M is not known.
62	NOT V	Other		A62V is associated with multinucleoside resistance caused by Q151M; its effect in the absence of Q151M is not known. $listMutsIn{62(NOT V)} is a highly unusual mutation at this position.
65	N	NRTI	Yes	K65R causes intermediate resistance to ddI, ABC, 3TC, FTC, and TDF, and low-level resistance to d4T. K65R causes AZT hypersusceptibility. K65N is an extremely rare mutation that may have a similar effect. 
65	R	NRTI	Yes	K65R causes intermediate resistance to ddI, ABC, 3TC, FTC, and TDF, and low-level resistance to d4T. K65R causes AZT hypersusceptibility.
65	NOT NR	NRTI		K65R/N are known NRTI-resistance mutations. $listMutsIn{65(NOT NR)} is a highly unusual mutation at this position.
67	EG	NRTI	Yes	D67N contributes some degree of resistance to each of the NRTIs except 3TC and FTC. It usually occurs with mutations at positions 70 or 215. D67E/G occur in heavily treated patients but their precise effect on NRTI susceptibility is not known.
67	N	NRTI	Yes	D67N contributes some degree of resistance to each of the NRTIs except 3TC and FTC. It usually occurs with mutations at positions 70 or 215.
67	d	NRTI	Yes	Amino acid deletions (d) in this region occur uncommonly. They occur in combination with other NRTI mutations and contribute decreased susceptibility to each of the NRTIs.
67	NOT EGNd	NRTI		D67N contributes some degree of resistance to each of the NRTIs except 3TC and FTC. It usually occurs with mutations at positions 70 or 215. D67E/G occur in heavily treated patients but their precise effect on NRTI susceptibility is not known. $listMutsIn{67(NOT EGNd)} is a highly unusual mutation at this position.
69	NSAI	NRTI	Yes	T69N/S/A/I are NRTI-selected mutations but their effect on NRTI susceptibility is not known.
69	D	NRTI	Yes	T69D, a mutation originally identified for its role in causing ddC reistance, is associated with decreased susceptibility to ddI and d4T.
69	G	NRTI	Yes	T69G occurs in isolates with a deletion at position 67 but its effect on NRTI susceptibility is not known.
69	i	NRTI	Yes	Amino acid insertions (i) at this position occur in about 1%-2% of heavily treated persons. Together with TAMs, they confer high-level resistance to each of the NRTIs. Most susceptibility data are available for double amino acid insertions. However, insertions of 1 or >2 amino acids also occur.
69	NOT ADGINSi	NRTI		T69D/N/S/G/A/I are NRTI-selected mutations. $listMutsIn{69(NOT ADGINSi)} is a highly unusual mutation at this position.
70	EG	NRTI	Yes	K70E/G reduces TDF, ABC, DDI, and to a lesser extent 3TC and FTC susceptibility. 
70	R	NRTI	Yes	K70R causes low-level AZT, d4T, and possibly TDF resistance. 
70	NOT EGR	NRTI		K70R causes low-level AZT, d4T, and possibly TDF resistance. K70E/G reduces TDF, ABC, DDI, and to a lesser extent 3TC and FTC susceptibility. $listMutsIn{70(NOT EGR)} is an unusual mutation at this position.
74	I	NRTI	Yes	L74V reduces susceptibility to ddI and ABC susceptibility and increases susceptibility AZT and TDF. 
74	V	NRTI	Yes	L74V reduces susceptibility to ddI and ABC susceptibility and increases susceptibility AZT and TDF. L74I appears to have a similar effect but may not increase AZT and TDF susceptibility.
74	NOT IV	NRTI		L74V reduces susceptibility to ddI and ABC susceptibility and increases susceptibility AZT and TDF. L74I appears to have a similar effect but may not increase AZT and TDF susceptibility. $listMutsIn{74(NOT IV)} is a highly unusual mutation at this position.
75	I	NRTI	Yes	V75I increases multinucleoside resistance caused by Q151M when present with F77L and F116Y; its effect in the absence of Q151M is not known.
75	TMAS	NRTI	Yes	V75T/M/A/S reduce d4T and possibly ddI susceptibility.
75	L	NRTI	No	V75L does not appear to be associated with reduced NRTI susceptibility.
75	NOT AIMSTL	NRTI		V75M/T/A/S/I are NRTI-selected mutations. $listMutsIn{75(NOT AIMSTL)} is a highly unusual mutation at this position.
77	L	NRTI	Yes	F77L increases multinucleoside resistance caused by Q151M when present with V75I or F116Y; its effect in the absence of Q151M is not known.
77	NOT L	NRTI		F77L increases multinucleoside resistance caused by Q151M when present with V75I or F116Y. $listMutsIn{77(NOT L)} is a highly unusual mutation at this position
90	I	NNRTI	No	V90I is a common polymorphism that was weakly associated with decreased ETR response in the DUET studies. However, it has minimal if any effect on NNRTI susceptibility. 
90	NOT I	Other		None
98	G	NNRTI	Yes	A98G reduces NVP susceptibility by 2 to 3-fold. It is selected by NRTIs and NNRTIs. It was associated with a decreased ETR response in the DUET studies but it has little if any effect on ETR susceptibility.
98	S	Other	Yes	A98S is a common polymorphism that does not reduce NNRTI susceptibility.
98	NOT GS	Other		None
100	I	NNRTI	Yes	L100I usually occurs in combination with K103N. By itself it causes intermediate resistance to NVP, DLV, and EFV, and 2 to 4-fold decreased ETR susceptibility. In combination with K103N it causes high-level resistance to NVP, DLV, and EFV and 10 to 20-fold decreased ETR susceptibility.  L100I increases susceptibility to AZT and TDF.
100	NOT I	NNRTI		L100I usually occurs in combination with K103N. By itself it causes intermediate resistance to NVP, DLV, and EFV, and 2 to 4-fold decreased ETR susceptibility. In combination with K103N it causes high-level resistance to NVP, DLV, and EFV and 10 to 20-fold decreased ETR susceptibility.  $listMutsIn{100(NOT I)} is a highly unusual mutation at this position.
101	E	NNRTI	Yes	K101E causes intermediate resistance to NVP and DLV and low-level resistance to EFV and ETR.
101	HN	NNRTI	Yes	K101H/N are rare NNRTI-associated mutations with uncertain phenotypic and clinical effects. K101H was weakly associated with a decreased ETR response in the DUET studies.
101	P	NNRTI	Yes	K101P nearly always occurs with K103N and in this setting causes high-level resistance to NVP, DLV, and EFV. By itself K101P reduces ETR susceptibility 6-fold. 
101	Q	NNRTI	Yes	K101Q is weakly associated with NNRTI therapy and minimally reduces susceptibility to each of the NNRTIs.
101	R	Other	No	K101R is an uncommon polymorphism that has not been associated with decreased NNRTI susceptibility.
101	NOT EHNPQR	NNRTI		K101E/P/N/H/Q are NNRTI-selected mutations. $listMutsIn{101(NOT EHNPQR)} is a highly unusual mutation at this position.
103	EQ	NNRTI	No	K103E/Q are rare mutations that have not been associated with resistance to the current NNRTIs.
103	TH	NNRTI	Yes	K103T/H are rare mutations that appear to be associated with intermediate/high-level resistance to NVP, DLV, and EFV. 
103	N	NNRTI	Yes	K103N causes high-level resistance to NVP, DLV, and EFV. By itself it has no effect on ETR susceptibility. However, it has a synergistic effect with L100I and possibly K101P on ETR susceptibility.
103	R	NNRTI	Yes	K103R occurs in about 1%-2% of untreated persons and by itself has no effect on NNRTI susceptibility. However, the combination of K103R + V179D, reduces NVP, DLV, and EFV susceptibility by about 15-fold.
103	S	NNRTI	Yes	K103S causes high-level resistance to NVP and intermediate/high-level resistance to DLV and EFV. 
103	NOT EHNQRST	NNRTI		K103N/S/T/H are NNRTI-resistance mutations. K103R/E/Q are variants that usually do not cause NNRTI resistance. $listMutsIn{103(NOT EHNQRST)} is a highly unusual mutation at this position.
106	A	NNRTI	Yes	V106A causes high-level resistance to NVP and DLV, and low/intermediate resistance to EFV. Its effect on ETR, if any, appears to be minimal.
106	I	NNRTI	No	V106I is a common polymorphism that was associated with decreased ETR response in the DUE study. However, it does not decrease NNRTI susceptibility. 
106	L	NNRTI	No	V106L is a rare polymorphism that does not appear to be associated with NNRTI resistance.
106	M	NNRTI	Yes	V106M causes high-level resistance to NVP, EFV, and DLV but does not appear to decrease ETR susceptibility except as a marker of past NNRTI therapy.
106	NOT AIML	NNRTI		V106A/M are NNRTI-resistance mutations. V106I/L are polymorphisms that do not appear to cause NNRTI resistance. $listMutsIn{106(NOT AIML)} is a highly unusual mutation at this position.
108	I	NNRTI	Yes	V108I causes low-level reductions in susceptibility to each of the NNRTIs except ETR. It occasionally occurs in the absence of NNRTI therapy.
108	NOT I	NNRTI		V108I causes low-level reductions in susceptibility to each of the NNRTIs except ETR. It occasionally occurs in the absence of NNRTI therapy. $listMutsIn{108(NOT I)} is a highly unusual mutation at this position.
115	F	NRTI	Yes	Y115F causes intermediate resistance to ABC and low-level resistance to TDF.
115	NOT F	NRTI		Y115F causes intermediate resistance to ABC and low-level resistance to TDF. $listMutsIn{115(NOT F)} is a highly unusual mutation at this position.
116	Y	NRTI	Yes	F116Y increases multinucleoside resistance caused by Q151M when present with F77L or V75I; its effect in the absence of Q151M is not known.
116	NOT Y	NRTI		F116Y increases multinucleoside resistance caused by Q151M when present with F77L or V75I; its effect in the absence of Q151M is not known. $listMutsIn{116(NOT Y)} is a highly unusual mutation at this position.
118	I	NRTI	Yes	V118I occurs in ~2% of untreated persons and with increased frequency in persons receiving multiple NRTIs. It causes low-level resistance to 3TC and possibly to other NRTIs when present with E44A/D and/or one or more TAMs.
118	NOT I	Other		$listMutsIn{V118(NOT I)} is a highly unusual mutation at this position.
138	A	NNRTI	Yes	E138A is a polymorphism that has been recently added to the list of mutations associated with decreased ETR response in the DUET studies.
138	G	NNRTI	Yes	E138G is a rare mutation that has been reported to emerge in patients with ETR failure. It may contribute to decreased ETR susceptibility in combination with other mutations.
138	K	NNRTI	Yes	E138K is selected in vitro by ETR and reduces its susceptibility by about 5-fold. E138K reduces to susceptibility other NNRTIs by about 2 to 5-fold.
138	Q	NNRTI	Yes	E138Q is weakly associated with NNRTI therapy. It may contribute to decreased NNRTI susceptibility in certain genetic contexts.
138	NOT AGKQ	NNRTI		E138AGKQ are weakly assocated with decreased ETR suscepitibility. $listMutsIn{138(NOT AGKQ)} is an unusual mutation at this position.
151	L	NRTI	Yes	By itself, Q151M causes intermediate-to-high level resistance to AZT, ddI, d4T, and ABC; and low-level resistance to TDF. With changes at the associated positions 75, 77, and 116, Q151M confers high-level resistance to AZT, ddI, d4T, and ABC; intermediate resistance to TDF, and low-level resistance to 3TC and FTC. Q151L is a rarely observed transitional mutation that may precede the emergence of the Q151M.
151	M	NRTI	Yes	By itself, Q151M causes intermediate-to-high level resistance to AZT, ddI, d4T, and ABC; and low-level resistance to TDF. With changes at the associated positions 75, 77, and 116, Q151M confers high-level resistance to AZT, ddI, d4T, and ABC; intermediate resistance to TDF, and low-level resistance to 3TC and FTC. 
151	NOT LM	NRTI		By itself, Q151M causes intermediate-to-high level resistance to AZT, ddI, d4T, and ABC; and low-level resistance to TDF. With changes at the associated positions 75, 77, and 116, Q151M confers high-level resistance to AZT, ddI, d4T, and ABC; intermediate resistance to TDF, and low-level resistance to 3TC and FTC. $listMutsIn{151(NOT LM)} is a highly unusual mutation at this position.
179	DE	NNRTI	Yes	V179D/E cause low-level reductions in susceptibility to NVP, EFV, and DLV. V179D occurs in about 1% of untreated persons and reduces the susceptibility of each NNRTI by about 2-fold.  The combination of K103R + V179D reduces the susceptibility of NVP, DLV, and EFV by about 15-fold; the combination's effect on ETR is not known. V179D was associated with a decreased response to ETR in the DUET studies.
179	F	NNRTI	Yes	V179F nearly always occurs in combination with Y181C. By itself, V179F has no effect on ETR susceptibility but in combination with Y181C, it reduces ETR susceptibility >100-fold and causes low-level EFV resistance. It is selected in vivo by ETR.
179	I	Other	Yes	V179I is a common polymorphism which occurs more commonly in NNRTI-treated isolates. However, it does not reduce NNRTI susceptibility.
179	T	NNRTI	Yes	V179T is a rare mutation that was weakly associated with a decreased response to ETR in the DUET studies. It has no apparent effect on NNRTI susceptibility
179	NOT DEFIT	NNRTI		$listMutsIn{V179(NOT DEFIT)} is an unusual mutation at this position.
181	CIV	NNRTI	Yes	Y181C/I/V cause high-level resistance to NVP and DLV and low-level resistance to EFV. Y181C/I/V reduces ETR susceptibility by 5 to 15-fold and provide the mutational foundation for the development of higher levels of ETR resistance. Y181C increases susceptibility to AZT and TDF.
181	S	NNRTI	Yes	Y181C/I/V cause high-level resistance to NVP and DLV and low-level resistance to EFV. Y181C/I/V reduces ETR susceptibility by 5 to 15-fold and provide the mutational foundation for the development of higher levels of ETR resistance. Y181S is a rare NNRTI-selected mutation that causes intermediate-high resistance to NVP and DLV. Few data are available for EFV and ETR.
181	NOT CISV	NNRTI		Y181C/I/V cause high-level resistance to NVP and DLV and low-level resistance to EFV. Y181C/I/V reduces ETR susceptibility by 5 to 15-fold and provide the mutational foundation for the development of higher levels of ETR resistance. $listMutsIn{181(NOT CISV)} is a highly unusual mutation at this position.
184	VI	NRTI	Yes	M184V/I cause high-level in vitro resistance to 3TC and FTC and low-level in vitro resistance to ddI and ABC. M184V/I increase susceptibility to AZT, TDF, and d4T.
184	NOT IV			M184V/I cause high-level in vitro resistance to 3TC and FTC and low-level in vitro resistance to ddI and ABC. M184V/I increase susceptibility to AZT, TDF, and d4T. $listMutsIn{184(NOT IV)} is a highly unusual mutation at this position.
188	C	NNRTI	Yes	Y188C causes high-level resistance to NVP and low-level resistance to EFV and DLV; its effect on ETR is not known.
188	H	NNRTI	Yes	Y188H causes intermediate resistance to NVP, EFV, and DLV and has been selected in vitro by ETR.
188	L	NNRTI	Yes	Y188L causes high-level resistance to NVP and EFV, intermediate resistance to DLV, and potentially low-level resistance to ETR.
188	F	NNRTI	No	Y188F is a rare mutation at this position of uncertain significance. It is often an artifact of the two-base pair change required for the emergence of Y188L.
188	NOT CHLF			Y188L/H/C are NNRTI-resistance mutations. $listMutsIn{188(NOT CHLF)} is a highly unusual mutation at this position.
190	A	NNRTI	Yes	G190A causes high level resistance to NVP, intermediate resistance to EFV, and increased DLV susceptibility. It has no effect on ETR susceptibility but was associated with a decreased response to ETR in the DUET studies.
190	CTV	NNRTI	Yes	G190C/T/V are rare mutations that cause high-level resistance to NVP and EFV and increased susceptibility to DLV. Their effect on ETR is not known.
190	EQ	NNRTI	Yes	G190E/Q cause high-level resistance to NVP and EFV and intermediate resistance to DLV. G190E + Y181C is associated with >100-fold decreased ETR susceptibility.
190	S	NNRTI	Yes	G190S causes high-level resistance to NVP and EFV and increases DLV susceptibility. Although it was on the list of 13 mutations associated with decreased ETR response in the DUET studies, it does not appear to decrease ETR susceptibility.
190	NOT ACEQSTV	NNRTI		G190A/S/E/Q/T/V/C are NNRTI-resistance mutations. $listMutsIn{190(NOT ACEQSTV)} is a highly unusual mutation at this position.
210	FS	NRTI	Yes	L210W contributes resistance to each of the NRTIs except 3TC and FTC. It usually occurs with the mutations M41L and T215Y. L210F/S occur rarely and are of unknown significance.
210	W	NRTI	Yes	L210W contributes resistance to each of the NRTIs except 3TC and FTC. It usually occurs with the mutations M41L and T215Y.
210	NOT FSW	NRTI		L210W contributes resistance to each of the NRTIs except 3TC and FTC. It usually occurs with the mutations M41L and T215Y. $listMutsIn{210(NOT FSW)} is a highly unusual mutation at this position.
215	SCDEIV	NRTI	Yes	T215S/C/D/E/I/V are transitions between wild type and the mutations Y and F. Most do not reduce NRTI susceptibility but their presence may suggests that T215Y or F may also be present.
215	F	NRTI	Yes	T215F causes AZT and D4T resistance and reduces susceptibility to ABC, ddI, and to a lesser extent TDF.
215	Y	NRTI	Yes	T215Y causes AZT and D4T resistance and reduces susceptibility to ABC, ddI, and TDF particularly when it occurs in combination with M41L and L210W.
215	NOT CDEFISVY	NRTI		T215Y causes AZT and D4T resistance and reduces susceptibility to ABC, ddI, and TDF particularly when it occurs in combination with M41L and L210W. T215S/C/D/E/I/V are transitions between wild type and the mutations Y and F. Most do not reduce NRTI susceptibility but their presence may suggests that T215Y or F may also be present. $listMutsIn{215(NOT CDEFISVY)} is a highly unusual mutation at this position.
219	EQ	NRTI	Yes	K219Q/E decrease AZT and probably d4T susceptibility when present with K70R or T215Y/F but have little if any effect on the remaining NRTIs.
219	NR	NRTI	Yes	K219N/R occur commonly in heavily NRTI-treated patients. Their effect on NRTI susceptibility is uncertain.
219	WDH	NRTI	Yes	K219W/H/D are uncommon NRTI-selected mutations at this position.
219	NOT ENQRWDH	NRTI		K219Q/E/N/R/W/D/H are NNRTI-associated mutations. $listMutsIn{219(NOT ENQRWDH)} is an unusual mutation at this position.
221	Y	NNRTI	No	H221Y is an uncommon NNRTI-associated mutation. Its phenotypic effect on current NNRTIs has not been studied. 
221	NOT Y	NNRTI		H221Y is an uncommon NNRTI-associated mutation. Its phenotypic effect on current NNRTIs has not been studied. $listMutsIn{221(NOT Y)} is a highly unusual mutation at this position.
225	H	NNRTI	Yes	P225H increases EFV resistance when present in combination with K103N.
225	NOT H	NNRTI		P225H increases EFV resistance when present in combination with K103N. $listMutsIn{225(NOT H)} is a highly unusual mutation at this position.
227	C	NNRTI	Yes	F227C is a rare mutation which which has emerged in vitro with ETR. It has been associated with a wide range in phenotypic resistance to each of the NNRTIs.
227	L	NNRTI	Yes	F227L usually occurs in combination with V106A and in this setting is associated with high level resistance to NVP and intermediate resistance to DLV and EFV. Its effect on ETR is not known.
227	NOT CL	NNRTI		F227LC are NNRTI-associated mutations. $listMutsIn{F227(NOT CL)} is a highly unusual mutation at this position.
230	L	NNRTI	Yes	M230L causes intermediate-to-high-level resistance to each of the NNRTIs. It has been selected in vitro by ETR and reduces ETR susceptibility by about 3 to 10-fold depending on the assay.
230	NOT L	NNRTI		M230L causes intermediate-to-high-level resistance to each of the NNRTIs. $listMutsIn{230(NOT L)} is a highly unusual mutation at this position.
234	I	NNRTI	Yes	L234I has been selected in vitro by ETR and it acts synergistically with Y181C to reduced susceptibility. Its clinical significance and effect on other NNRTIs is not known.
234	NOT I	NNRTI		L234I is an uncommon NNRTI associated mutation. $listMutsIn{234(NOT I)} is a highly unusual mutation at this position.
236	L	NNRTI	Yes	P236L causes high-level DLV resistance.
236	NOT L	NNRTI		P236L causes high-level DLV resistance. $listMutsIn{236(NOT L)} is a highly unusual mutation at this position.
238	N	NNRTI	Yes	K238T is an NNRTI-selected mutations that usually occur in combination with K103N in which case it causes high-level resistance to NVP, EFV, and DLV. Its effect on ETR is not known. K238N is a rarer NNRTI-selected mutation at this position. Its phenotypic effect is not known.
238	R	Other	Yes	K238R is a naturally occurring variant that is common in some non-B subtypes and does not reduce NNRTI susceptibility.
238	T	NNRTI	Yes	K238T is an NNRTI-selected mutations that usually occur in combination with K103N in which case it causes high-level resistance to NVP, EFV, and DLV. Its effect on ETR is not known. 
238	NOT NRT	NNRTI		K238T/N are NNRTI-associated mutations. K238R is a common polymorphism that is not associated with NNRTIs. $listMutsIn{238(NOT NRT)} is a highly unusual mutation at this position.
318	F	NNRTI	Yes	Y318F is an uncommon mutation that causes high-level DLV resistance and low/intermediate NVP resistance.
318	NOT F			Y318F is an uncommon mutation that causes high-level DLV resistance and low/intermediate NVP resistance. $listMutsIn{318(NOT F)} is a highly unusual mutation at this position.
333	DE	Other	No	G333D/E are polymorphisms that occur more frequently in persons receiving NRTIs than in untreated persons. They may facilitate AZT resistance in isolates that contain M184V and multiple TAMs.
333	NOT DE			None
348	I	NRTI	No	N348I causes low-level reductions in AZT and NVP susceptibility.
348	NOT I	NRTI	No	N348I causes low-level reductions in AZT and NVP susceptibility. $listMutsIn{348(NOT I)} is an unusual mutation at this position.