Table 4.

Allele frequencies of variant CYP2D6 alleles (%) in different ethnic populations ²⁰⁹.

Allele variants	Enzyme function	Caucasian	Asian	Black- African	Ethiopian, Saudi-Arabian
*1xN, *2xN	gene duplication: increased enzyme activity	1-5	0-2	2	10-29
*4	splicing defect: inactive enzyme	12-21	1	2	1-4
*5	deletion: no enzyme	2-7	6	4	1-3
*10	instable enzyme	1-2	41-51	6	3-9
*17	reduced affinity to substrate	0	0	20-35	3-9
*41	low protein expression, impaired function	8.4	2.6