Frequency of CYP2B6 Alleles in Major Iranian Ethnicities, Affecting Response to Efavirenz

Table 4

The effects of CYP2B66 (516G > T), CYP2B64 (785A > G), and CYP2B65 (1459C > T) polymorphisms in efavirenz metabolization and mutated allele frequency of CYP2B6 polymorphisms worldwide, especially in West Asia.

Polymorphism	CYP2B6	Efavirenz metabolization	Proposed mechanism	Studies’ findings (mutated allele percentage)
				Current study	Iran (Mazani) [6]	Iran (Baloch) [25]	West Asian [26]	Italian [27]	Caucasian [28]	German [29]	United Kingdom [30]
CYP2B66 (516G > T)	Reduced expression [31, 32]	Poor metabolization	(i) Aberrant splicing [33]; (ii)Higher protein expression in COS-1 cells [34]; (iii) Demethylation catalytic activity with the substrate 4-trifluoromethylcoumarin [34]	41.50	48	10.4	21.5	29.1	25.6	25	28.1
CYP2B64 (785A > G)	Reduced expression [32]	Poor metabolization	(i) Higher protein expression in COS-1 cells [34]; (ii) Demethylation catalytic activity with the substrate 4-trifluoromethylcoumarin [34]	37.41	43	23.1	14.7	2.82	4	5	1.1
CYP2B65 (1459C > T)	Increased activity [35]	Rapid metabolization	(i) Unknown.	24.49	0.08	2.4	NR	17.3	10.9	9.5	12.2

COS, CV-1 (simian) in origin and carrying the SV40 genetic material; NR, not reported.