One in every two hundred pregnancies in Europe ends in stillbirth (intrauterine fetal demise – IUFD), with IUFD being responsible for 60% of perinatal deaths. Stillbirth is defined as an infant dying inside the womb after the 14th week of gestation and so far, researchers have no explanation for the causes of almost half of these stillbirths.

Genetic scientists from Germany, Italy and the US have now come an important step further in unveiling the mystery that surrounds the causes of stillbirth.

They discovered that almost 8% of these unexplained deaths might be caused by specific genetic heart conditions.

Ms Alice Ghidoni, a PhD student from Italy’s Pavia University will present the findings of their study at the annual conference of the European Society of Human Genetics, which reveals for the first time that some IUFD deaths may be caused by cardiac channelopathies, i.e. hereditary diseases in which the heartbeat rhythm is disturbed.

Ghidoni explains:

“Since we knew that 10-15% of sudden infant death syndrome cases carry genetic variants associated with long QT syndrome or Brugada syndrome, we decided to investigate whether sudden death due to malignant arrhythmias could underlie some cases of IUFD as well.”

After obtaining consent from the parents, the researchers conducted a molecular screening on stillborn fetuses, whose death remained unexplained after a thorough post-mortem investigation.

They focused on the mutation of three genes of which two were involved in long QT and one was involved in both long QT and Brugada syndromes and discovered three disease-causing variants that did not occur in over 1,000 ethnically matched controls.

Long QT and Brugada syndromes are irregular heartbeat conditions that can induce arrhythmias due to mutations in cardiac ionic channels, leading to cardiac arrest, syncopes and sudden death. The conditions are best known for causing sudden unexplained death in young adults, and although these syndromes can be detected in comprehensive and accurate clinical exams and genetic tests, they remain unidentified in most cases until a sudden death has occurred.

Ms Ghidoni states that genetic testing is still relatively rare in IUFD, even though it is an important tool for exploring the causes of unexplained death.

She states:

“The most common causes of fetal death are chromosomal abnormalities, infections, fetal-maternal hemorrhages, and maternal diseases. Most of these are relatively easy to identify. Since genetic screening is a long, expensive and complicated procedure, currently it is not routinely performed in cases where an autopsy has not shown the cause of death. However, such molecular investigation could be very useful to identify specific genetic defects occurring in the family, so that future pregnancies can be monitored with close clinical follow-up. In some cases, life-saving treatment could be given.”

If doctors can identify that a fetus has a gene mutation for a cardiac channelopathy, the mother can be treated with drugs, such as beta-blockers, which are also administered to adults with long QT syndrome.

It was not possible to systematically collect the fetuses parental DNA because the study was conducted in different centers and countries, although the researchers intend to expand their research by enlarging the study population and by collecting DNA from all family members. Because cardiac channelopathies are genetic, doctors can perform genetic tests not just in those who are at risk of stillbirth but also in those family members who may not know that they may potentially have a fatal heart condition.

Ms Ghidoni explains: “We have also identified new candidate genes which may be linked to cardiac channelopathies, and we will investigate them in our follow-up work. Our current work shows that nearly 3% of IUFDs may be caused by a genetic variant with a cardiac disease-causing role, and another 5% by a variant that may predispose to disease. We believe that the new candidate genes may enlarge this field yet further. This is vitally important because we can then depict a clear picture of arrhythmic risk in perinatal life, both before and after birth.”

She concludes, saying:

“We believe that it is very important to increase knowledge of these genetic disorders among pediatric cardiologists and gynecologists and that genetic testing should be included in post-mortem analysis. Many more lives can be saved if there is sufficient awareness of these devastating conditions among healthcare professionals, as well as among the affected families who in many cases have already suffered enough.”

Written by Petra Rattue (ends)