Rs17221854

rs17221854, also known as Arg583Cys or R583C, is a SNP in the KCNQ1 gene on chromosome 11.

The rs17221854(T) allele has been reported as associated with long QT syndrome.

Additionally, a person who developed QT prolongation and torsade de pointes while taking the drug dofetilide carried this (T) allele, leading the authors to hypothesize that this mutation was responsible for the patient's drug response.

This variant meets the criteria published in 2013 by the ACMG regarding incidental findings in exome or genome sequencing, as a variant that they do recommend informing a patient about.