Sudden cardiac death may be prevented in some families with hereditary cardio-genetic disorder
A 43 year old male, Amit, had come to the Genetic Clinic with his wife who was filled with anxiety. The man was leading a healthy lifestyle with a balanced diet, regular physical exercise, non smoker and a teetotaler. He had had two episodes of fainting (syncope) after which his cardiologist had carried out various tests. The results of these tests indicated a strong possibility that Amit was at risk for sudden cardiac death likely due to certain genetic mutations known to cause abnormal heart beat. A plan of action was immediately put into place, which included a surgical intervention to help reduce Amit’s risk of sudden cardiac death with a device called an implantable cardioverter defibrillator (ICD).
Based on guidelines, Amit’s cardiologist appropriately sought genetic testing to confirm the suspected genetic condition infamous for causing sudden deaths, but successfully treated with an ICD across the globe. Amit and his wife were referred for a pre-test genetic counseling appointment with Dr. Risha Nahar Lulla at MapMyGenome.
Our Genetic Counselor recommended Whole Exome Sequencing (WES). WES is a sophisticated genomics-based test that sequences all genes, and is extremely useful in situations when a specific clinical picture is known to be caused by one of many genes. Results of WES revealed a mutation in both copies of the KCNE1 gene, greatly increasing Amit’s risk of heart failure, she confirming his cardiologist’s concerns. This confirmed genetic diagnosis gave Amit as well as his cardiologist confidence in proceeding according to recommendations and an ICD device was successfully implanted.
ICDs continuously monitor a patient’s cardiac rhythm and treat cardiac arrhythmias, potentially preventing sudden cardiac death. ICDs are indicated for patients who have a high risk for sudden cardiac death due to abnormal heart rhythms. Current preventive treatment for most genetic cardiac disorders relies upon the ICD in high risk individuals, which can detect and correct an abnormal and potentially lethal heart rhythm. Individuals often first present with an abnormal heart beat or history of sudden cardiac death, typically in their teens and early adulthood.
Because genes are shared within families, a secondary benefit of genetic testing in Amit’s case was that we were able to screen additional family members to identify those at risk, as well as those not at risk, for genetic cardiovascular diseases. After analyzing Amit’s genetic family history, targeted genetic testing for the specific mutation found in Amit was recommended to his brother since knowing the genetic risk can help in surveillance and early intervention and management. Amit’s brother, to everyone’s relief, did not have the mutation. He neither needed an ICD, nor needed to worry about a potentially life-threatening heart condition.
Genetic counseling helped both the cardiologist as well as the patient to understand the implications of the genetic test report to the patient, his daughter and other family members. Most families have a history of sudden deaths in the parents or grandparents which should be considered a red flag for the individuals as well as doctors, and referral for genetic counseling and/or testing must be made. Such a referral is key in prevention and well being.