Express diagnostics of hereditary diseases in newborns
Up to a third of newborns who enter the intensive care unit immediately after birth have hereditary diseases. In some cases, despite the severity of the symptoms, the genetic cause of the problem is very difficult to identify. To date, thousands of hereditary diseases have been described, but specialists have a very limited set of tests that can detect only the most common mutations.
Genome-wide sequencing makes it possible to search for multiple diseases simultaneously, but the high cost, complexity of interpreting the results and time costs in most cases make it unacceptable.
Researchers of the Children's Mercy Hospital In Kansas City, Missouri, working under the leadership of Stephen Kingsmore, they proposed a faster and simpler system for searching for mutations corresponding to certain symptoms, designed for doctors who do not have special genetic education.
Previously, genome-wide sequencing helped out specialists who were lost in guesses about the causes of incomprehensible diseases. So, in 2011, the results obtained as a result of genome sequencing helped to choose a treatment method for 14-year-old twins suffering from neurological impairment of motor function. In another case, genome-wide sequencing helped to determine that severe inflammatory bowel disease has a genetic cause and its symptoms can be alleviated by bone marrow transplantation. However, in both cases, it took several weeks and a group of experts to solve the problem.
In order to order a new test, the pediatrician will have to describe the symptoms of the newborn by selecting the necessary drop-down menu items. After that, the software will identify the genes presumably involved in the formation of these symptoms. Upon completion of genome sequencing, the program will search for and analyze mutations only in the intended target genes, which will significantly reduce the duration of the analysis. Developers have access to new DNA sequencing equipment developed by Illumina (San Diego, California). This experimental equipment allows the genome to be sequenced in just 25 hours.
The researchers used the new system to analyze the genomes of five children, including two brothers with an unknown disease. In 4 out of 5 cases, they were able to establish the exact or probable genetic causes of diseases. They also sequenced fragments of the parents' genomes. The results showed that some mutations first appeared in the genome of children, while others were present in recessive form in the genomes of both parents. The entire analysis cycle, from obtaining informed consent to a preliminary diagnosis, took approximately 50 hours, not counting the time spent on sending DNA samples and correspondence between the Illumina laboratory and the clinic. According to Kingsmore's calculations, the cost of sequencing and analysis of a single genome, including verification of variants in a laboratory certified for clinical analysis, is $13,500.
Despite the fact that none of the diagnoses made in the study did not affect the therapy, according to Kingsmore, the information about the diagnosis itself is very useful. Doctors can stop conducting expensive invasive examinations, and families can get qualified advice on planning future pregnancies. Moreover, the identification of new genes, mutations in which cause various diseases, allows us to formulate new hypotheses for fundamental research.
Article by Saunders C. J. et al. Rapid Whole-Genome Sequencing for Genetic Disease Diagnosis in Neonatal Intensive Care Units is published in the journal Science Translational Medicine.
Evgeniya Ryabtseva
Portal "Eternal youth" http://vechnayamolodost.ru based on the materials of Nature News:
Rapid test pinpoints newborns' genetic diseases in days.
12.10.2012