Table 1.

KCNQ1 Mutations in Chinese LQTS Families

Kindred	Nucleotide Change*	Codon* Change	Protein Domain	Clinical Characteristics of Mutation Carriers	Trigger for Arrhythmias
F2	572T>C	L191P	Intracellular loop between S2 and S3	I:1, QTc 480–500 ms; syncope, 1 episode II:3, QTc 600 ms; syncope, 3 episodes; inverted T-wave (V1–V5), appearance of U-wave II:5, sudden death at age of 2 years III:1, proband: QTc 580 ms; TdP, syncope, 2 episodes (early morning sleeping) III:2, QTc 480 ms III:3, QTc 520 ms	Sleeping or Awakening from sleep
F1	824T>C	F275S	S5	I:2, QTc 470 ms; TdP; sudden death triggered by excitement II:7, QTc 580 ms; history of palpitation III:4, proband: QTc 530 ms; syncope; sudden death at age of 19 years triggered by skiing, stress, and excitement	Excitement Exercise Stress
F8	830C>T	S277L	S5	I:2, sudden death. II:1, proband, QTc 680 ms; sudden death II:3, QTc 470 ms; no symptom. II:4, QTc 470 ms; no symptom.	Exercise Excitement
F4	917G>T	G306V	Pore	I:1, QTc 540 ms; no symptom. II:4, QTc 600 ms; no symptom. II:6, proband, QTc 560 ms; syncope III:3, QTc 500 ms; no symptom	Exercise Excitement

^*Positions of nucleotides and codons for KCNQ1 are based on NM-000218 and AF000571, respectively. TdP, torsade de pointes.