TABLE 2

Description of subjects presenting with genotype-phenotype discordance

CYP2D6 phenotype was determined from the urinary ratio of dextromethorphan to dextrorphan (DM/DX ratio) with PM status defined as a DM/DX ratio >0.3. One subject (case 4) presented as PM 2 weeks after birth, but acquired IM status (0.03 < DM/DX < 0.3 as defined by Gaedigk et al., 2003b) within 2 months of life. Each DM/DX ratio represents a phenotype assessment. Originally discordant and subsequently revised genotypes are presented.

Sample Identification	Ethnicity	Age Group	DM/DX Ratio (Age)^a	Original Genotype (Discordant)	Revised Genotype (Concordant)
Case 1	AA	Adult	0.849	4/10	4/36
Case 2	AA	Infant	3.905 (11 d)	4/10	4x2/36
			1.595 (34 d)
Case 3	AA	Infant	1.613 (15 d)	4/10	4x2/36
			3.824 (31 d)
			0.932 (65 d)
			0.328 (123 d)
			2.026 (185 d)
Case 4	AA	Infant	0.381 (14 d)	2/10 ^b	2/36 ^b
			0.241 (27 d)
			0.019 (64 d)

AA, African American.
↵ a Postnatal age in days when phenotyping was conducted.
↵ b Both genotypes are discordant with the DM/DX ratio at 14 days because of the presence of CYP2D6*41 but are concordant with the subsequent phenotype assessments.