The purpose of this review is to emphasize that single gene disorders are an important and sometimes unrecognized cause of progressive chronic kidney disease. We provide an overview of the benefits of making a genetic diagnosis, the currently available genetic testing methods and examples of diseases illustrating the impact of a genetic diagnosis.
Although there are now a number of monogenic renal diseases, only a few, such as autosomal dominant polycystic kidney disease (ADPKD), are generally diagnosable without genetic testing. Complicating clinical diagnosis is that many diseases that classically have characteristic renal or extrarenal findings, often present with an incomplete or overlapping phenotype that requires additional testing to be uncovered. Advances in sequencing technology and bioinformatic processing now give us the ability to screen the entire human genome or exome or an organ-limited subset of genes quickly and inexpensively permitting the unbiased interrogation of hundreds of genes, thus removing the need for precision in clinical diagnosis prior to testing.
We provide an overview of the principal phenotypes seen in chronic kidney disease with a focus on the cystic diseases and ciliopathies, the glomerular diseases, disorders of renal development and the tubulointerstitial diseases. In each of these phenotypes, we provide a listing of some of the important genes that have been identified to date, a brief discussion of the clinical diagnosis, the role of genetic testing and the differentiation of distinct genetic disorders from acquired and genetic phenocopies.
aDivision of Nephrology, Department of Internal Medicine
bDepartment of Pediatrics
cInterdepartmental Program in Molecular Medicine
dRenal Genetics Clinic, University of Iowa Carver College of Medicine
eVeterans Affairs Medical Center, Iowa City, USA
Correspondence to Christie P. Thomas, MD, Department of Internal Medicine, Division of Nephrology, SE419 GH, University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, IA, 52242, USA. Tel: +319 3564216; fax: +319 3562381; e-mail: firstname.lastname@example.org