Table 1. Classification criteria used to identify off-target pharmacogenetic variants from the PharmGKB database.

Step	Filter	Number variants
1	Exclude synonymous and non-coding variants	561
2	Include variants that have type:toxicity/ADR	339
3	For drug and gene pairs, exclude variants with additional effect types other than Toxicity/ADR	273
4	Gene containing variant is NOT an ADME process gene OR annotated in GO with ‘xenobiotic metabolic process’ OR ‘transporter’	196
5*	Variant not containing an entry in clinVAR	142

Note:

^*For 30 variants used as a truth set, we performed an additional detailed literature search to definitively classify each variant as type A or type B.