[THE GENETIC BASIS OF CHRONIC KIDNEY DISEASE IN CHILDREN AND YOUNG ADULTS].

Chronic kidney disease (CKD) in children arises from heterogeneous disease etiologies. A large portion is caused by monogenic diseases, which are also known as single-gene disorders or Mendelian diseases. Understanding the genetic underpinnings of childhood and young adulthood, CKD has increased significantly over the last decade due to increased availability of genetic testing as well as clinician's awareness. This led to the discovery of numerous genes that, if mutated, may lead to early onset CKD. So far, hundreds of CKD-causing genes have been reported, explaining ~30% of cases among children and ~10% in adults. Nonetheless, the genetic diagnostic yield varies markedly across different study cohorts, depending on clinical presentation, geographic region and ethnicity. In clinical practice, the diagnosis of genetic kidney diseases may be challenging due to variable expressivity, incomplete penetrance, low index of suspicion, lack of overt symptoms at early disease stages and insufficient availability of next generation sequencing methods. Detection of monogenic causes of CKD provides definitive diagnosis that might end a long distressing odyssey. It enables personalized surveillance and treatments, spares unnecessary diagnostic procedures such as kidney biopsies, prevents the use of inappropriate therapies, and might also prevent incompatible transplantation from an affected relative. Additionally, it allows family genetic consulting and early diagnosis of asymptomatic family members. The notable progress in the field of genetics in addition to the diagnostic challenges of genetic kidney disease led to the emergence of nephrogenetics - a rapidly evolving subspecialty of nephrology and genetics. Preferably, the management of patients with genetic kidney disease should be multi-disciplinary and include collaboration between nephrologists, geneticists and additional consultants as needed. We anticipate that a routine use of genetic testing for CKD patients, as well as additional advancements in genetic discoveries, will further lead to understanding of genetic CKD patho-mechanisms and to the development of novel gene-based therapies. In this review, we will discuss the genetic basis of CKD in children and young adults. We will also discuss the clinical approach to patients with suspected genetic kidney disease.