Abstract 11133: Prevalence and Types of Long QT Syndrome among Children with Hearing Loss
Introduction. Long QT syndrome (LQTS) associated with sensorineural hearing loss (SNHL) is known as the Jervell and Lang Nielsen syndrome (JLNS), an autosomal recessive disorder. Autosomal dominant LQTS is more common but has not been associated with SNHL.
Hypothesis. Children with severe to profound hearing loss are at higher risk for LQTS, therefore ECG screening can be useful for early diagnosis of LQTS.
Methods. We conducted statewide, prospective ECG screening of infants and children (≤6 y) with unilateral or bilateral, severe or profound, sensorineural or mixed hearing loss in California in 2009-2011. Subjects were identified through the state newborn hearing screening and special education programs. Participants were interviewed about medical and family histories and had initial screening by 12-lead ECGs. Children with histories suggesting arrhythmia, syncope, or sudden death, or a QTc ≥ 450 ms had a repeat ECG. DNA sequencing of 12 genes involved in LQTS was performed if the repeat QTc was ≥ 450 ms.
Results. We completed ECG screening on 711 subjects, and severe-profound SNHL was verified by audiogram reviews in 523 (74%). Among the 523, ages were 27 ± 20 mo (range 1-75) with 48% females and 63% Hispanics. Reported races were: 80% white, 3.8% black, 7.1% Asian, and 8.6% other. Sixty-two (12%) had a repeat ECG, and 18 (3.4%) had gene testing. No subject had homozygous or compound heterozygous LQTS mutations, as in JLNS. However, 3 subjects (0.6%) were heterozygous for a LQTS mutation-- 2 girls with a KCNQ1 variant (IVS12+1 G>A or Glu444fs) and a boy with an SCN5A variant (Arg1958Stop). QTc intervals were 457, 472, and 456 ms, respectively. The results represent a 14-fold higher relative risk for LQTS among children with congenital severe-profound SNHL (P = 0.002). In addition, 2 subjects with QTc intervals of 464 and 459 ms had variants of uncertain significance (KCNJ2 Arg325His or KCNH2 Arg1033Trp, respectively).
Conclusions. In this population-based study of children with SNHL, we found a 14-fold increased risk for heterozygous LQTS. No recessive LQTS cases (JLNS) were seen. Hearing loss may be an unrecognized part of heterozygous LQTS, depending on the specific mutation. ECG screening for LQTS should be performed when an infant's hearing loss is confirmed.
- © 2012 by American Heart Association, Inc.