A major international study involving researchers from the Danish iPSYCH psychiatry project has identified new genes that increase the risk of febrile convulsions. And in contrast to previous research, the study did not find a correlation between genes associated with mental disorders and genes associated with an increased risk of febrile convulsions.

Seeing their child having febrile convulsions can be a very frightening experience for parents, who often think their child is about to die. The majority of children experience febrile convulsions only once or possibly a few times, but approximately seven per cent of children with febrile convulsions will later develop epilepsy.

Researchers from iPSYCH and Statens Serum Institut (SSI) have now identified seven new genes associated with an increased risk of developing febrile convulsions. The genes are involved in mechanisms that determine how children react to fever and how the brain cells work.

The research has just been published in the neurological journal Brain.

Susceptible to fever

The researchers analysed DNA variants in 7,635 children from Denmark and Australia who had experienced one or more episodes of febrile convulsions. They also analysed 83,966 children who had not had febrile convulsions.

“The results are important in our attempt to explain why some children experience febrile convulsions, while others do not. Some children are particularly susceptible to fever – and we have now shown that this susceptibility is associated with the genes that the children are born with,” says Julie Werenberg Dreier, who is one of the researchers behind the findings.

The study shows that children with more ‘febrile convulsion genes’ are younger at the time of their first seizure, and are more often hospitalised with febrile convulsions subsequently, compared with children with fewer ‘febrile convulsion genes’.

“This suggests that the overall risk of suffering febrile convulsions is determined by several different genes, each of which carries a small risk, but when these genes appear together in the same child, this will result in a higher risk of febrile convulsions,” explains Jakob Christensen, who has also contributed to the study.

No connection to mental disorders

The researchers also examined the correlation between febrile convulsions and the risk of mental disorders. Previous studies have actually shown a correlation here.

“There’s been some concern that in the long term, the child could suffer from psychiatric disorders as a result of febrile convulsions, but we didn’t find any increased genetic liability of febrile convulsions among persons with mental disorders compared to those without. On the contrary, the incidence of genes associated with febrile convulsions was slightly lower in those who had a psychiatric diagnosis compared to those who didn’t. So, this suggest that the genes associated with febrile convulsions are not the same as the genes associated with psychiatric disorders,” explains Jakob Christensen.

Although the researchers were unable to find a correlation between genes associated with febrile convulsions and genes associated with psychiatric disorders, they did discover a correlation between febrile convulsions and epilepsy.

“We found that some of the genes associated with febrile convulsions are also associated with epilepsy, and this may explain why children with febrile convulsions have an increased risk of epilepsy later in life. Understanding the genetic similarities and differences between febrile convulsions and epilepsy is a fascinating research area which we are planning to investigate in future studies” says Jakob Christensen.

Febrile convulsions

Febrile convulsions are seizures in children under the age of five who have a fever above 38.5 C. Up to five per cent of all children experience febrile convulsions and they are slightly more common in boys than in girls. Febrile convulsions are the most common form of abnormal brain activity during childhood.

Background for the results

  • The study is a genetic association study
  • The partners in the study are IPSYCH Aarhus University, Aarhus University Hospital, and Statens Serum Institut (SSI).
  • The study is financed by the Lundbeck Foundation.
    The scientific article can be read in Brain