Jervell and Lange-Nielsen syndrome (JLNS): Likelihood Ratios

Introduction: - Syndrome characterized by congenital deafness, prolonged Q-T interval, and syncopal attacks

Hearing loss is congenital, bilateral, and severe to profound

AR inheritence, genetically heterogeneous with mutations in KVLQT1 and KCNE1

These genes encode for subunits of a potassium channel expressed in the heart and inner ear

Romano-Ward syndrome is an AD inherited genetic disease with long Q-T syndrome without associated

The prolonged Q-T interval can lead to ventricular arrhythmias, syncopal episodes, and death in childhood

Effective treatment with â-adrenergic blockers reduces mortality from 71% to 6%

Cummings 5th Ed. Chapter 147 Genetic sensorineural hearing loss

Prevalence

Population / Calculator	Prevalence	Comments / Study / Link
Among children with congenital sensorineural hearing loss	0.21%	PMID:9326683
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The likelihood ratios of findings for Jervell and Lange-Nielsen syndrome (JLNS) are listed below. See the left navigation bar to change the display.

Pre-Test Probability (Prevalence): %.	Post-Test Probability (Predictive Value): %.	Switch to display mode.
Note that calculating probabilities from more than one** finding is inherently inaccurate because findings are not independent. (For example, using two positive findings that share a common pathogenesis is likely to overestimate the true probability.)

Findings With Unspecified Accuracy
Finding	Result	+LR	-LR
[ + ] Sensorineural hearing loss (SNHL)		No accuracy specified.
Study: no study specified.
[ + ] Prolonged QTc		No accuracy specified.
Study: no study specified.
[ + ] KVLQT1 and KCNE1 genetic mutations		No accuracy specified.
Study: no study specified.