학술논문
Beyond the exome: what's next in diagnostic testing for Mendelian conditions
Document Type
Working Paper
Author
Wojcik, Monica H.; Reuter, Chloe M.; Marwaha, Shruti; Mahmoud, Medhat; Duyzend, Michael H.; Barseghyan, Hayk; Yuan, Bo; Boone, Philip M.; Groopman, Emily E.; Délot, Emmanuèle C.; Jain, Deepti; Sanchis-Juan, Alba; Diseases, Genomics Research to Elucidate the Genetics of Rare; Consortium; Starita, Lea M.; Talkowski, Michael; Montgomery, Stephen B.; Bamshad, Michael J.; Chong, Jessica X.; Wheeler, Matthew T.; Berger, Seth I.; O'Donnell-Luria, Anne; Sedlazeck, Fritz J.; Miller, Danny E.
Source
Subject
Language
Abstract
Despite advances in clinical genetic testing, including the introduction of exome sequencing (ES), more than 50% of individuals with a suspected Mendelian condition lack a precise molecular diagnosis. Clinical evaluation is increasingly undertaken by specialists outside of clinical genetics, often occurring in a tiered fashion and typically ending after ES. The current diagnostic rate reflects multiple factors, including technical limitations, incomplete understanding of variant pathogenicity, missing genotype-phenotype associations, complex gene-environment interactions, and reporting differences between clinical labs. Maintaining a clear understanding of the rapidly evolving landscape of diagnostic tests beyond ES, and their limitations, presents a challenge for non-genetics professionals. Newer tests, such as short-read genome or RNA sequencing, can be challenging to order and emerging technologies, such as optical genome mapping and long-read DNA or RNA sequencing, are not available clinically. Furthermore, there is no clear guidance on the next best steps after inconclusive evaluation. Here, we review why a clinical genetic evaluation may be negative, discuss questions to be asked in this setting, and provide a framework for further investigation, including the advantages and disadvantages of new approaches that are nascent in the clinical sphere. We present a guide for the next best steps after inconclusive molecular testing based upon phenotype and prior evaluation, including when to consider referral to a consortium such as GREGoR, which is focused on elucidating the underlying cause of rare unsolved genetic disorders.