From SNPedia
The (T) form of this SNP causes an amino acid change (from proline to serine) at position 34 of the
CYP2D6 protein. The associated allele is also known as CYP2D6.10 or CYP2D6*10.
If two copies of this (or similar) changes are inherited, poor metabolism ('PM') of debrisoquine [PMID 2211621] is observed.
Other drugs metabolized by CYP2D6 include dextromorphan, sparteine, nortriptyline, and codeine.
Nakamura et al [PMID 12051754] suggest that thermal instabilities and reduced intrinsic clearance by the protein encoded by the rs1065852(T) allele are the main reasons Orientals show lower metabolic activities than Caucasians for drugs metabolized mainly by CYP2D6, since this (T) allele occurs in higher frequency in Orientals.
It is also suggested that poor metabolizers of debrisoquine will be poor metabolizers of metoprolol, diltiazem (brand name cardizem), and propafenone. [PMID 3437726]
