Family Tree Helps Define Risk of Sudden Death
However, researchers said that screening from the age of 5 until 60 is justified for first-degree family members of those with CPVT. In addition, if a carrier is asymptomatic after the age of 60, it’s likely he or she will not need a pacemaker or implantable cardioverter defibrillator.
In Brugada syndrome, which causes fainting and a rapid heart rhythm that can lead to sudden cardiac death, researchers observed excess deaths between ages 40 and 59 (SMR 1.72), primarily for men. The risk increased when the age range was narrowed to between 40 and 49 (SMR 2.0).
“We have to be careful not to draw conclusions for families with arrhythmias caused by different mutations,” Nannenberg said in a statement. “However, these new data can guide screening. In LQTS1, for example, we advise starting genetic and heart screening of first-degree family members at a very young age.”
Risk factors
Although sudden infant death syndrome can strike any infant, researchers have identified several factors that may increase a baby’s risk. They include:
- Sex. Boy babies are more likely to die of SIDS.
- Age. Infants are most vulnerable during the second and third months of life.
- Race. For reasons that aren’t well understood, black, American Indian or Eskimo infants are more likely to develop SIDS.
- Family history. Babies who’ve had siblings or cousins die of SIDS are at higher risk of SIDS themselves.
Maternal risk factors
The risk of SIDS is also affected by maternal factors associated with the pregnancy, including:
- Mother under the age of 20
- Smoking cigarettes
- Drug or alcohol use
- Inadequate prenatal care
The Family Tree Mortality Ratio method allowed researchers to study the mortality of inherited arrhythmias “at a time when the disease was not known and patients received no treatment.” The method, however, did not allow morbidity associated with the mutations to be extracted, researchers acknowledged.
They also suggested that more large families be studied with this method to determine if the data can be generalized to other populations.
This study was supported by grants from the Interuniversity Cardiological Institute of the Netherlands, the Dutch Heart Foundation, the Fondation Leducq Trans-Atlantic Network of Excellence, and Zorg Onderzoek Nederland Medische Wetenschappen.
Co-author Wade is member of the advisory board of PGxHealth. All other authors reported they had no conflicts of interest.
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Primary source: Circulation: Cardiovascular Genetics
Source reference: Nannenberg EA, et al “Mortality of inherited arrhythmia syndromes; insight into their natural history” Circ Cardiov Gen 2012; DOI:10.1161/CIRCGENETICS.111.961102.