A young one the sudden death of a person can remain without a clear explanation, even if the cause of death is carefully investigated. Sometimes the background is a rare hereditary heart disease that is not visible in a standard autopsy.
Fresh a Finnish study raises one such reason. When the PPA2 gene defect is inherited from both parents, even a small amount of alcohol can be life-threatening for some.
Those with a genetic defect predisposing to the disease should avoid alcohol completely.
“It’s absolutely a life-saving thing,” says the pediatric cardiology professor Tiina Ojala From HUS’s New Children’s Hospital.
Researchers with the help of a large Finnish family, found out how the rare PPA2 gene defect affects the heart. 23 family members participated in the study.
The subjects underwent genetic tests and some also underwent heart tests, such as cardiac film, ultrasound and magnetic resonance imaging. In addition, the researchers investigated, among other things, alcohol consumption and infections.
Nine members of the family had inherited the gene defect from both mother and father. The PPA2 gene defect is inherited covertly, i.e. the disease can break out when the gene defect is passed on to the child from both parents.
Based on the research, only the genetic defect inherited from the other parent did not cause the disease.
Two 15-year-old boys had a serious heart attack after consuming alcohol. One died suddenly and the other fell ill with severe myocarditis.
Myocardial damage may be part of the event, but a serious cardiac event is likely to result from the combined effect of several factors. The dead boy had also recently had a respiratory infection.
According to Ojala, the disease related to PPA2 deficiency is very rare.
Surprising the finding in the study was at the other extreme.
Seven other people with the same genetic defect had lived to adulthood without heart symptoms suggestive of PPA2 disease. The oldest of them was 81 years old. In the past, very few such asymptomatic adults were known.
The essential thing is that the asymptomatic adults had practically avoided alcohol. According to Ojala, this was the only protective factor that the researchers could identify. Other genetic and environmental factors can also influence the manifestation of the disease.
The results support the notion that alcohol can be an important trigger of a serious heart event, but the data does not show that it alone determines who gets sick.
“Very often there can be a mild viral infection in the background at the same time, but it can be very mild,” says Ojala.
According to him, in some forms of the PPA2 disease, a viral infection can trigger a life-threatening situation on its own, especially in very young children.
A genetic defect identification is important if no other clear reason can be found for a serious cardiac event or sudden death.
“If no explainable reason can be found for a heart event in a young person, then it is often necessary to continue with these genetic tests,” says Ojala
He emphasizes genetic studies especially when a young person dies suddenly and the autopsy does not find a proper explanation.
If a genetic defect is found, genetics doctors usually start mapping the closest relatives and, if necessary, go further in the family.
Finding a genetic defect is also important for heredity counseling. If a gene defect causing a serious disease is identified in the family, embryo diagnostics can be used to prevent its inheritance to the child.
Due to this rare disease, Ojala does not consider screening the entire population possible.
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