[EXOME ANALYSIS - A GAME CHANGER IN PEDIATRICS].

INTRODUCTION: Thirteen years after the completion of the human genome project, the determination of the genomic sequence of the coding parts of the DNA (the exones, hence the exome), has turned into a primary diagnostic tool in daily use in clinical practice. The Department of Genetics at Hadassah was the first in Israel to introduce exome analysis as a robust diagnostic tool into the pediatric departments. Till now 2600 exomes were analyzed at Hadassah, 850 of them in 2016 alone. Exome analysis is cheap and fast, enabling precise and non-invasive diagnosis for a vast array of genetic disorders and congenital malformations. The unique composition of the population which the hospital serves (marked by a high rate of consanguinity) enabled reaching diagnosis in 65% of the cases, twice the rate in medical centers worldwide. The results of this analysis enable genetic counseling to patients' families and prevention of serious disorders. Moreover, the results contribute to the understanding of the biological basis of newly identified disorders and in certain cases assist in the management of the patients. The major limitation of exome analysis is the multitude of identified variants which exist in any individual and which challenge our ability to pick the disease-causing variant. In the case of a disease-causing variant in a new gene, experimental proof is required to validate the causality of the variant; occasionally, an incidental finding with possible clinical significance is identified, raising serious ethical concerns. In this article, we will review the use of this technology through the experience of three pediatric departments at Hadassah.