Fabry Screening in Men With Pacemakers Not Supported in Study
Low prevalence of Fabry disease found in nearly 500 men screened
A program that screened nearly 500 men with implanted pacemakers for Fabry disease found that none of them had the genetic disorder.
The findings “suggest that the prevalence of [Fabry disease] in male patients requiring permanent pacing is very low and does not justify a systematic screening,” according to researchers.
The study, “Screening of Fabry disease in patients with an implanted permanent pacemaker,” was published in the International Journal of Cardiology.
Fabry disease is caused by mutations in the GLA gene, located on the X chromosome — one of the two sex-determining chromosomes in humans. This gene provides instructions for making the enzyme alpha-galactosidase A (Gal A), which is needed to break down certain fatty molecules in cells.
Heart disease is common among people with Fabry disease, who can experience heart rhythm abnormalities (arrhythmias) or an unusually slow heart rate (bradycardia). Implanted pacemakers are often used to help manage these issues in Fabry patients.
However, it is not clear whether some people with Fabry disease develop heart problems without other obvious symptoms of Fabry, which could lead to delays in diagnosis and proper treatment.
484 men with implanted pacemakers were screened for Fabry disease
A team led by researchers in the Czech Republic screened 484 men, ages 35 to 65, who had received implanted pacemakers for heart issues which are comparable to those often seen in Fabry disease. Their goal was to see whether any of the men had Fabry disease.
“The current study was designed to assess whether screening for [Fabry disease] in patients with unexplained bradycardia requiring implantation of permanent [pacemaker] is relevant,” the researchers wrote.
In initial testing of Gal A activity and levels of related fatty molecules, nine patients showed profiles suggestive of Fabry and were referred for genetic testing.
However, genetic testing revealed that none of these patients had Fabry disease. Three of them had a pseudodeficiency — a genetic variation known to cause a false-positive for Fabry in biochemical tests of the enzyme.
“The negative result of our screening is the most likely given by low prevalence of [Fabry disease] in general population compared to common cardiovascular diseases leading to pacemaker need, including coronary artery disease, myocarditis [heart muscle inflammation], or electrolyte [salt level] disorders,” the researchers wrote.
“Our findings do not advocate a routine screening for [Fabry disease] in all adult males with clinically significant bradycardia,” they wrote.
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