|
Hypertrophic Cardiomyopathy (HCM), an abnormal thickening
of heart muscle, affects about 1 of 500 people. In some,
the heart’s valves don’t work properly;
in others, the thickened muscle obstructs blood flow
away from the heart. HCM scrambles the cells of the
heart muscles, which can interrupt the heart’s
electrical impulses and cause arrhythmia.
Chest pain, shortness of breath and palpitations (feeling
the heart beat) as well as dizziness or fainting spells
(often during or after exercise) are symptoms of HCM.
However, sometimes a seemingly healthy person has no
apparent symptoms and dies suddenly as the result of
severe arrhythmia. HCM-related sudden cardiac death
can occur in young patients (less than 30 years of age)
and often is the cause of death in young athletes who
die suddenly.
Geneticists have identified 11 genes and more than
200 mutations for HCM. Mutations have been found in
sarcomeric proteins, which have a role in the heart’s
contractions. Three genes in particular—the beta
-myosin heavy chain (MyHC); the cardiac troponin T (cTnT);
and myosin binding protein-C (MyBP-C) account for about
two-thirds of all HCM cases.
The genetic test for HCM involves drawing a person’s
blood for direct DNA sequencing. The test is done in
two panels, one for the five most common mutations,
the second for another three genes; together, the panels
have a 55 percent to 70 percent detection rate. Clinical
testing for HCM includes echocardiography; chest X-ray;
and cardiac catheterization.
Because HCM is an autosomal dominant disorder, it is
important for all first degree relatives of an HCM patient
to be tested for the gene mutation. For children in
particular, testing is important as clinical symptoms
may not appear until adulthood.
The treatment of hypertrophic cardiomyopathy is complex.
Symptoms can be managed by various medications or surgical
interventions. In those patients at risk for sudden
death, implantation of a defibrillator is mandatory.
|
Conditions
Printer
Friendly Page