Until recently, the only way to screen family members for HCM was through a yearly echocardiogram. Today, genetic testing is the standard. This is a cost-effective way to find out which relatives need to be followed and which individuals no longer have to be concerned about developing HCM.
Genetic testing can be done from a blood sample. It is important for two reasons: patients can find out more about their own prognosis, and they learn if family members, who have so far shown no signs of HCM, are at risk of developing the condition in the future.
Sometimes the gene can also tell us if patient is likely to develop electrical abnormalities or arrhythmias and can also indicate if a person is at risk for sudden cardiac death. (While the risk of sudden cardiac death is roughly five percent at adolescence, it tapers off with age. Only one percent of all patient with HCM are at risk for sudden cardiac death.)
The same gene mutation can also manifest itself at different ages within a single family, and not everyone with the genetic predisposition will develop HCM. For example, a newborn may have severe HCM, her father may have been diagnosed in his 20s, and the grandfather may have a completely normal echocardiogram.
How Genetic Testing Works
We begin with an educational session, explaining what the testing will reveal and how family members will benefit from this knowledge.
A blood sample is sent to the lab, where DNA, or genetic material, is isolated. The genes most commonly responsible for HCM are read like words on a page. We are looking for a typo or misspelling that causes a mistake in the protein made by that gene.
Genetic testing is either covered in full by most insurance policies or the patient has a maximum out-of-pocket cost of $100.
Genetic Testing and Family Planning
Genetic testing can help in family planning. If only one parent tests positive for a HCM gene, the mutation can be passed on to the next generation.
Some couples opt for prenatal genetic testing for HCM while others opt for in vitro fertilization with genetic testing for HCM before the embryo is implanted in the womb.
Women with HCM may not be able to carry a child; these individuals may choose to genetically test prior to implanting the embryo in a surrogate.
Many patients come to us after there has been a sudden death in the family. We work with medical examiners all across the country, and do post-mortem testing for HCM when necessary.
If an autopsy confirms the diagnosis of HCM, we can counsel the entire family. As genetic detectives, we figure out who is at risk and needs to be followed closely. Family members who don't carry the gene are not only relieved of worry, they are also spared the expense of repeated monitoring and medical tests.