{{Genotype
|rsid=1800462
|allele1=C
|allele2=C
|magnitude=3.5
|repute=Bad
|summary=incapable of detoxifying
}}
poor [[drug metabolism]] of some medications.

potentially encoding a variant incapable of detoxifying byproducts of certain antineoplastic and immunosuppressant drugs.

http://blog.23andme.com/health-traits/do-you-know-how-youll-respond-to-thiopurine-medications/