Long QT and Jervell & Lange-Nielsen

1. Long QT andJervell & Lange-Nielsen

2. Disease of heart electrophysiology Long QT syndrome (LQT)

3. Caused by mutations in ion channels (eg KCNQ1, KCNE1, KCNH2, KCNE2) Can be asymptomatic or result in irregular heartbeats, dizziness, fainting fits or sudden death. Long QT syndrome (LQT)

4. Early onset, severely prolonged QT (50% of patients die before the age of 15 without intervention) Congenital sensorineuraldeafness Two mutations in KCNQ1 and/or KCNE1 (often truncating) Jervell & Lange-Nielsen syndrome (JLNS)

5. Diagnostic tests: genotype-phenotype correlations can help to advise on appropriate therapy and prevention eg Beta blockers can control symptoms in over most individuals with KCNQ1 but are not protective if patients have an SCN5A mutation eg Patients with KCNQ1 mutations should avoid competitive sport while those with KCNH2 mutations should avoid loud noises or emotional triggers Clinical utility of testing

6. Family tests: Affected individuals can help to clarify pathogenicity of an uncertain variant can reduce the likelihood of a second pathogenic variant within the family Unaffected individuals Negative result gives relief and means the patient can be released from clinical screening Positive result can aid compliance with clinical screening and preventative measures Clinical utility of testing

7. KCNQ1 R518X Family

8. KCNQ1 R518X Family R518X/N

9. KCNQ1 R518X Family R518X/N R518X/N N/N R518X/N

10. KCNQ1 R518X Family N/N R518X/N R518X/N N/N R518X/N R518X/N N/N R518X/N

11. KCNQ1 R518X Family N/N R518X/N R518X/N N/N R518X/N R518X/N JLNS N/N R518X/N

12. KCNQ1 R518X Family N/N R518X/N R518X/N N/N R518X/N R518X/N JLNS R518X/N N/N R518X/N

13. KCNQ1 R518X Family N/N R518X/N R518X/N N/N R518X/N R518X/N JLNS R518X/N Full screen = R518X/N N/N R518X/N

14. KCNQ1 R518X Family N/N R518X/N R518X/N N/N R518X/N ? R518X/N JLNS R518X/N Full screen = R518X/N N/N R518X/N

15. Asked clinician (Geneticist) for more clinical details regarding JLNS patient Severity eg QTc Age of onset Also suggested Connexin gene testing Strategy

16. Asked clinician (Geneticist) for more clinical details regarding JLNS patient Cardiologist did not respond to enquiries Also suggested Connexin gene testing Results

17. Asked clinician (Geneticist) for more clinical details regarding JLNS patient Cardiologist did not respond to enquiries Also suggested Connexin gene testing Came back positive for two mutations expected to cause deafness Enabled us to resume genetic testing within this family Results

18. Importance of testing all affected individuals within a pedigree before beginning predictive testing (even for known pathogenic mutations) Importance of checking the whole pedigree (not just the proband) prior to initiating genetic testing in the lab Importance of communication between cardiologists, geneticists and scientists Clinicians are trained to pattern spot but scientists may have more detailed knowledge of particular specialities Utility of other clinical/genetic tests Lessons