• long-QT syndrome;
  • genetics;
  • arrhythmia

Introduction: Data regarding risk factors and clinical course of patients affected with Jervell and Lange-Nielsen syndrome (JLNS), an autosomal recesssive form of the congenital long-QT syndrome (LQTS), are limited to several reported cases and a retrospective analysis.

Methods and Results: We prospectively followed-up 44 JLNS patients from the U.S. portion of the International LQTS Registry and compared their clinical course with 2,174 patients with the phenotypically determined dominant form of LQTS (Romano-Ward syndrome [RWS]) and a subgroup of 285 patients with type 1 LQTS (LQT1). Mean (±SD) corrected QT interval (QTc) in the JLNS, RWS, and LQT1 groups were 548 ± 73, 500 ± 48, and 502 ± 46 msec, respectively (P < 0.001). The cumulative rates of cardiac events from birth through age 40 among JLNS and RWS patients were 93% (mean [±SD] age: 5.0 ± 7.0 years) and 54% (mean [±SD] age: 14.2 ± 9.3 years), respectively (P < 0.001). The JLNS:RWS and JLNS:LQT1 adjusted hazard ratios (HR) for cardiac events were highest among patients with a baseline QTc ≥550 msec (HR = 15.83 [P < 0.001] and 13.80 [P < 0.001], respectively). Among JLNS patients treated with beta-blockers, the cumulative probability of LQTS-related death was 35%; defibrillator therapy was associated with a 0% mortality rate during a mean (±SD) follow-up period of 4.9 ± 3.4 years.

Conclusions: Patients with JLNS experience a high rate of cardiac and fatal events from early childhood despite medical therapy. Defibrillator therapy appears to improve outcome in this high-risk population, although longer follow-up is needed to establish its long-term efficacy.