Family Tree May Aid Treatment of Inherited Heart
TUESDAY, Feb. 28 (HealthDay News) -- Researchers who used family
trees dating back to 1811 to estimate the death risk for people
with inherited heart rhythm disorders say their findings can help
doctors determine when to screen and treat today's patients with
Sudden cardiac death can occur in apparently healthy people due
to heart rhythm disorders. Genetic testing can identify people with
an inherited heart rhythm disorder (arrhythmia), but that raises
questions about how and when to treat children who may not yet be
experiencing symptoms, which can take years to develop.
In the study, researchers used Dutch archives to reconstruct the
family trees for patients with inherited heart conditions,
including long QT syndrome, SCN5a-overlap syndrome, CPVT and
Brugada syndrome. The arrhythmia-associated gene mutations examined
in the study are rare. However, the children of people who carry
one of these mutations have a 50 percent chance of inheriting
The investigators were able to identify age ranges that were
associated with an increased risk of death among people who had the
mutations but had not yet been diagnosed or treated for the
Among the findings:
- The death risk for people with long QT syndrome -- a condition
related to sudden infant death syndrome -- was high between 1 and
19 years old, but was particularly high in the first 10 years of
life for those with a specific mutation (LQTS1). The risk of death
for people with two other mutations (LQTS2 and LQTS3) didn't
significantly increase until they were teens or adults.
- For people with SCN5a-overlap syndrome, death risk started to
rise at age 5 and became significant between ages 10 to 59, with a
peak between ages 20 to 39. People with this condition have a gene
mutation that affects the way heart cells respond to the heart's
internal electrical current.
- Catecholaminergic polymorphic ventricular tachycardia (CPVT) is
a condition that causes fainting, often during exercise or strong
emotions. Death risk for people with this condition was highest
between ages 20 to 39.
- Brugada syndrome causes fainting and a rapid heart rhythm that
can lead to sudden cardiac death. The risk of death for people with
this condition was highest between ages 40 to 59. Males were at
The study appears in the current issue of the journal
Circulation: Cardiovascular Genetics.
"We have to be careful not to draw conclusions for families with arrhythmias caused by different mutations," lead researcher Dr. Eline Nannenberg, a clinical geneticist at the Academic Medical Center in Amsterdam, said in a journal news release.
"However, this new data can guide screening. In LQTS1, we advise starting genetic and heart screening of first-degree family members (children, siblings, parents) at a very young age," Nannenberg added.
Female patients who have Brugada syndrome but no symptoms may
not need invasive treatment for the first 30 years of life, but
should follow standard prevention measures, such as fighting fever,
according to the researchers.
In people with SCN5a-overlap syndrome, it may be possible to
delay implantation of a pacemaker or implantable
cardioverter-defibrillator (ICD) until after age 5, they noted.
The Heart Rhythm Society has more about
heart rhythm disorders.
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