MHH Human Genetics: Whole-genome sequencing to bring the cause of rare diseases in critically ill children to light at an early stage
About four million people in Germany suffer from one of the many different rare diseases (SE) - especially seriously ill children who require intensive medical treatment. Most rare diseases are genetic and it often takes years before the correct diagnosis is found. Can the treatment of seriously ill children be improved by rapid genetic diagnosis? This question is being investigated by a team from Pediatrics and Human Genetics at Hannover Medical School (MHH) in the "Baby Lion" study. The focus is on decoding the genome, i.e. the entire genetic information of a human being, in just a few days.
According to the EU definition, a rare disease is one that occurs no more than five times in a population of 10,000. In total, more than 7,000 different rare diseases are known. "Seen in this light, a rare disease is not so rare after all," says Dr. Bernd Auber of the Institute of Human Genetics. For the study, he and his team are focusing on a special patient group: children in their first weeks and -months of life who are so ill that they need to be treated in an intensive care unit. "The cause of their symptoms is often not clear. No clear diagnosis can be made," explains Dr. Alexander von Gise, one of the pediatric intensivists involved in the study. Without an accurate diagnosis, however, no targeted treatment is possible, and a long journey of suffering and an odyssey from doctor to doctor often follows.
Genome of the child and parents is decoded
This is precisely where the Baby Lion study comes in, the first study of its kind in German-speaking countries. "Today, it is possible to completely decode the human genome in just a few days," explains Dr. Auber. Experts refer to this as whole genome sequencing (WGS). With the help of this very comprehensive and technically sophisticated diagnostic method, which generates huge amounts of data, even extremely rare genetic diseases can be identified. In the study, however, the experts in genetics and pediatrics want to decode not only the genome of the sick children, but also that of both parents. With this trio whole genome sequencing, the three genomes can be compared very precisely and relevant genetic changes in the child can be quickly identified.
"Being able to arrive at a diagnosis within a few days despite the large amounts of data would be a great help, especially for critically ill newborns," says Bettina Bohnhorst, head of the neonatal intensive care unit at MHH. In the USA and other countries, very good experiences have already been made with this novel diagnostic method. "In up to 40 percent of the children examined, the diagnosis of a genetic disease could be made," reports Dr. Michael Sasse, head of the pediatric intensive care unit at MHH. "Thanks to the early and reliable diagnosis, it is possible to provide targeted help to the children and their families more quickly. In rare cases, specific therapy can already be started now." Suffering paths can be shortened and unnecessary therapies and examinations can be avoided.
Dr. Auber’s team now wants to find out whether these findings can also be transferred to the German healthcare system. The study will include 100 children and their parents within one year. These are families who are cared for in the intensive care units of the pediatric clinic of the MHH and in other hospitals in Lower Saxony. In the study, the geneticists work closely with colleagues in the neonatology and pediatric intensive care units.
Genetic counseling for the families
To participate in "Baby Lion", a small amount of blood must be taken. After genome sequencing, the attending pediatricians discuss the result and further therapeutic steps with the parents. In addition, genetic counseling is offered to all families. After some time, the treating pediatricians and also the parents are asked about the effects of the rapid diagnosis on the child’s health development. Dr. Auber emphasizes, "If we can show with our study that the procedure has a positive effect on the treatment of the affected children, we hope to be able to offer rapid genome sequencing in standard care to all seriously ill children in the future."