Genetic Testing: Considerations for Pediatric Nephrologists

Diagnostic Yield of Next-Generation Sequencing in Patients With Chronic Kidney Disease of Unknown Etiology

Advances in next-generation sequencing (NGS) techniques, including whole exome sequencing, have facilitated cost-effective sequencing of large regions of the genome, enabling the implementation of NGS in clinical practice. Chronic kidney disease (CKD) is a major contributor to global burden of disease and is associated with an increased risk of morbidity and mortality. CKD can be caused by a wide variety of primary renal disorders. In about one in five CKD patients, no primary renal disease diagnosis can be established. Moreover, recent studies indicate that the clinical diagnosis may be incorrect in a substantial number of patients. Both the absence of a diagnosis or an incorrect diagnosis can have therapeutic implications. Genetic testing might increase the diagnostic accuracy in patients with CKD, especially in patients with unknown etiology. The diagnostic utility of NGS has been shown mainly in pediatric CKD cohorts, while emerging data suggest that genetic testing can also be a valuable diagnostic tool in adults with CKD. In addition to its implications for unexplained CKD, NGS can contribute to the diagnostic process in kidney diseases with an atypical presentation, where it may lead to reclassification of the primary renal disease diagnosis. So far, only a few studies have reported on the diagnostic yield of NGS-based techniques in patients with unexplained CKD. Here, we will discuss the potential diagnostic role of gene panels and whole exome sequencing in pediatric and adult patients with unexplained and atypical CKD.

Physicians' perspectives on the uncertainties and implications of chromosomal microarray testing of children and families

Chromosomal microarray analysis (CMA) has improved the diagnostic rate of genomic disorders in pediatric populations, but can produce uncertain and unexpected findings. This article explores clinicians' perspectives and identifies challenges in effectively interpreting results and communicating with families about CMA. Responses to an online survey were obtained from 40 clinicians who had ordered CMA. Content included practice characteristics and perceptions, and queries about a hypothetical case involving uncertain and incidental findings. Data were analyzed using nonparametric statistical tests. Clinicians' comfort levels differed significantly for explaining uncertain, abnormal, and normal CMA results, with lowest levels for uncertain results. Despite clinical guidelines recommending informed consent, many clinicians did not consider it pertinent to discuss the potential for CMA to reveal information concerning biological parentage or predisposition to late-onset disease, in a hypothetical case. Many non-genetics professionals ordering CMA did not feel equipped to interpret the results for patients, and articulated needs for education and access to genetics professionals. This exploratory study highlights key challenges in the practice of genomic medicine, and identifies needs for education, disseminated practice guidelines, and access to genetics professionals, especially when dealing with uncertain or unexpected findings.

Patient responses to genetic information: studies of patients with hereditary cancer syndromes identify issues for use of genetic testing in nephrology practice

Advances in the genetic basis of kidney disease may mean that genetic testing is increasingly important in reducing disease morbidity and mortality among patients. However, there is little research examining patient responses to genetic information for Mendelian and common kidney diseases. Existing research on kidney and other hereditary cancer syndromes can inform three major issues relevant to the nephrology context as follows: (1) how patients understand their risk of disease after genetic counseling and testing, (2) their emotional responses to the information, and (3) their uptake of recommended risk-reducing strategies. Prior research suggests that genetic counseling and testing may improve patient understanding of genetics, but patients still might not fully understand the meaning of their results for disease risk. Genetic counseling and testing does not appear to result in long-term negative emotional effects among patients who carry mutations or those who do not. Finally, although genetic counseling and testing may improve adherence to recommended screening strategies, adherence varies substantially across different risk-reduction options. Previous research also suggests that computer-based interventions might be a useful adjunct to genetic counseling approaches. Examining whether and how these prior findings relate to the context of hereditary kidney disease is an important area for future research.