JACC Case Rep. 2025 Dec 24:106521. doi: 10.1016/j.jaccas.2025.106521. Online ahead of print.
ABSTRACT
BACKGROUND: Prolonged QT interval on electrocardiogram along with sensorineural deafness is consistent with Jervell and Lange-Nielsen syndrome (JLNS). We report a case where genetic testing revealed different mutations for each manifestation.
CASE SUMMARY: A 5-year-old girl with congenital deafness presented with a history of palpitations. Baseline corrected QT (QTc) interval was 481 ms, and exercise stress test revealed QTc of 491 ms at 4 minutes of recovery. Family screening revealed another sibling to be deaf; screening electrocardiogram and exercise stress test also disclosed prolonged QTc interval. Genetic testing showed heterozygous pathogenic mutation in the KCNQ1 gene and a likely pathogenic homozygous mutation in the PCDH15 gene.
DISCUSSION: JLNS is the combination of prolonged QT interval with sensorineural deafness. Our patient was clinically suspected of having JLNS, however, genetic testing revealed the presence of 2 different mutations responsible for QT prolongation and deafness, representing the coincidence of 2 independent genetic disorders rather than JLNS only.
TAKE-HOME MESSAGE: Long QT syndrome in combination with deafness should be confirmed with genetic testing, as their combined presence can be a coincidental finding.
PMID:41563185 | DOI:10.1016/j.jaccas.2025.106521