“Hole” Exome Sequences: The Importance of Phenotyping to Fill the Gaps in Whole Exome Sequencing

Abstract

BackgroundWhole exome sequencing (WES) is commonly used for patients with nonspecific clinical features and conditions with genetic heterogeneity. However, a nondiagnostic exome does not exclude a genetic diagnosis, so history and physical examination is crucial to selecting appropriate genetic testing. CasesWe report three patients with three recognizable phenotypes: a seven-year-old female with classic Rett syndrome; a 28-year-old male with neuropathy, ataxia, and retinitis pigmentosa; and a 16-year-old male with mosaic, segmental, paternal uniparental disomy 14 who had nondiagnostic WES. ConclusionsDespite recognizable phenotypes they had diagnostic delays due to incorrect selection of genetic testing. This case series highlights the limitations of WES and reinforces the importance of utilizing patient history and physical examination to select initial testing. We will discuss appropriate testing for these patients and a consistent diagnostic algorithm that can be applied when approaching patients with unknown or uncertain clinical presentations.