Testing the Complex Child: CGH Array, WES, Clinical Exome, WGS

Purpose of Review: The purpose of this review was to compare existing strategies for evaluation of complex paediatric patients with newer techniques. Comparative genomic hybridization (CGH) array is the currently accepted first tier genetic test in the evaluation of a pediatric patient with complex physical and developmental anomalies. CGH provides an answer in only 15–20 % cases, and further genetic testing is required in the majority of cases. This has previously involved sequential single-gene tests, with low yield, significant costs and delay in diagnosis. Summary of Recent Findings: New genetic techniques allowing massively parallel sequencing of multiple genes are becoming a part of medical practice as they provide a reduction in cost and time. Current medical practice supports the use of limited genomic testing—‘gene panels’ and ‘clinical exomes’, as a second tier approach after CGH array testing. These approaches have already been shown to improve the diagnostic yield providing an answer for an additional 25 % of patients. Ultimately, it is likely that whole genome sequencing as a single genomic test could replace CGH array and more restricted genomic tests, as research experience is translated into medical practice. Several factors need to be overcome to make this a reality to ensure equitable access to a reliable test with appropriate diagnostic interpretation. © 2016, Springer Science + Business Media New York.