CYP2C19 (measured phenotype):
98.2 % extensive metabolizers
1.8 % poor metabolizers
(N=4301, Dutch healthy volunteers, 98.9% Caucasian, 68% males)(Tamminga et al., 1999).
[Note editor: Study-population is allocated to two categories: extensive or poor metabolizers; superextensive and slow metabolizers are not mentioned. Apparently extensive and superextensive are lumped together into ‘extensive metabolizers’ and slow and poor metabolizers into ‘poor metabolizers’]