BACKGROUND: Long QT syndrome (LQTS) is an inheritable arrhythmogenic disorder associated with life-threatening arrhythmic events (LAEs). In general, patients with LQTS2 (KCNH2) and LQTS3 (SCN5A) are considered to be a greater risk of LAEs than LQTS1 (KCNQ1) patients. Gender differences are also important. Series analyzing families with the same pathogenic variants may help in the progress of elaborating strong specific genotype-phenotype management strategies. In this manuscript, we describe the phenotype of seven unrelated families, carriers of the KCNQ1 G168R pathogenic variant. METHODS: we identified all consecutive index cases referred for genetic testing with LQTS diagnosis carriers of KCNQ1 G168R variant. Genetic and clinical screening for all available relatives was performed. RESULTS: we evaluated seven unrelated families, with a total 34 KCNQ1 G168R carriers (two obligated carriers died without available EKGs to evaluate the phenotype). All index cases but one were women and three of them presented with aborted sudden cardiac death (SCD) or syncope. The presence of sudden death in these families is notable, with a total of nine unexplained sudden deaths and four aborted SCD. Phenotype penetrance was 100% in women and 37.5% in men. CONCLUSIONS: KCNQ1 G168R is a pathogenic variant, with a high penetrance among women and mild penetrance among men. Risk for LAEs in this variant seems not negligible, especially among woman, and risk stratification should always be carefully evaluated.
BACKGROUND:Long QT syndrome (LQTS) is an inheritable arrhythmogenic disorder associated with life-threatening arrhythmic events (LAEs). In general, patients with LQTS2 (KCNH2) and LQTS3 (SCN5A) are considered to be a greater risk of LAEs than LQTS1 (KCNQ1) patients. Gender differences are also important. Series analyzing families with the same pathogenic variants may help in the progress of elaborating strong specific genotype-phenotype management strategies. In this manuscript, we describe the phenotype of seven unrelated families, carriers of the KCNQ1G168R pathogenic variant. METHODS: we identified all consecutive index cases referred for genetic testing with LQTS diagnosis carriers of KCNQ1G168R variant. Genetic and clinical screening for all available relatives was performed. RESULTS: we evaluated seven unrelated families, with a total 34 KCNQ1G168R carriers (two obligated carriers died without available EKGs to evaluate the phenotype). All index cases but one were women and three of them presented with aborted sudden cardiac death (SCD) or syncope. The presence of sudden death in these families is notable, with a total of nine unexplained sudden deaths and four aborted SCD. Phenotype penetrance was 100% in women and 37.5% in men. CONCLUSIONS:KCNQ1G168R is a pathogenic variant, with a high penetrance among women and mild penetrance among men. Risk for LAEs in this variant seems not negligible, especially among woman, and risk stratification should always be carefully evaluated.
Entities:
Keywords:
genetic testing; inheritable arrhythmogenic disorder; long QT syndrome
Authors: Silvia G Priori; Arthur A Wilde; Minoru Horie; Yongkeun Cho; Elijah R Behr; Charles Berul; Nico Blom; Josep Brugada; Chern-En Chiang; Heikki Huikuri; Prince Kannankeril; Andrew Krahn; Antoine Leenhardt; Arthur Moss; Peter J Schwartz; Wataru Shimizu; Gordon Tomaselli; Cynthia Tracy Journal: Heart Rhythm Date: 2013-08-30 Impact factor: 6.343
Authors: Hiten D Mistry; Laura A McCallum; Lesia O Kurlak; Iain A Greenwood; Fiona Broughton Pipkin; Rachel M Tribe Journal: Hypertension Date: 2011-07-05 Impact factor: 10.190
Authors: Arthur J Moss; Wataru Shimizu; Arthur A M Wilde; Jeffrey A Towbin; Wojciech Zareba; Jennifer L Robinson; Ming Qi; G Michael Vincent; Michael J Ackerman; Elizabeth S Kaufman; Nynke Hofman; Rahul Seth; Shiro Kamakura; Yoshihiro Miyamoto; Ilan Goldenberg; Mark L Andrews; Scott McNitt Journal: Circulation Date: 2007-04-30 Impact factor: 29.690
Authors: E H Locati; W Zareba; A J Moss; P J Schwartz; G M Vincent; M H Lehmann; J A Towbin; S G Priori; C Napolitano; J L Robinson; M Andrews; K Timothy; W J Hall Journal: Circulation Date: 1998-06-09 Impact factor: 29.690