A new study from Brown University, Providence has revealed that individuals with long QT syndrome (LQTS) are at an increased risk of sudden death due to irregular heartbeats, also known as a cardiac arrhythmias.
Lead researcher Gideon Koren generated two rabbit models of LQTS for the study provides new insight into the mechanisms by which these mutations might produce an irregular heartbeat in humans.
Mutations in several genes including KCNQ1 and KCNH2 have been shown to cause the disease.
For the study, the researchers used rabbits expressing either KCNQ1 or KCNH2 mutants that generate proteins with the same functional defect as found in individuals with LQTS.
The findings revealed that the heart defects observed in the rabbits mirrored those observed in individuals with LQTS and more than 50pct of the rabbits carrying the KCNH2 mutant died suddenly due to irregular heartbeats in their first year of life.
The proteins generated by the KCNQ1 and KCNH2 mutants prevented proteins generated by the corresponding non-mutant form of the gene from working and, importantly, no compensation for the loss of function of either protein was observed.
As compensation for the loss of function of the proteins generated by the KCNQ1 and KCNH2 mutants is observed in mouse models of LQTS these data provide important insight into the mechanisms underlying the disease.