Towards a Change in the Diagnostic Algorithm of Autism Spectrum Disorders: Evidence Supporting Whole Exome Sequencing as a First-Tier Test
Ana Arteche‐López, Maria José Gómez-Rodríguez, María Teresa Sánchez‐Calvín, Juan Francisco Quesada‐Espinosa, José Miguel Lezana Rosales, Carmen Palma Milla, Irene Gómez-Manjón, Irene Hidalgo Mayoral, Rubén Pérez de la Fuente, A. Diaz De Bustamante, M. Teresa Darnaude, Belén Gil-Fournier, Soraya Ramiro León, Patricia Ramos Gómez, Olalla Sierra Tomillo, Alexandra Juárez Rufián, Maria Isabel Arranz Cano, Rebeca Villares Alonso, Pablo Morales-Pérez, Alejandro Segura‐Tudela, Ana Camacho, Noemí Núñez, Rogelio Simón, Marta Moreno‐García, María Isabel Álvarez‐Mora
Abstract
Autism spectrum disorder (ASD) is a prevalent and extremely heterogeneous neurodevelopmental disorder (NDD) with a strong genetic component. In recent years, the clinical relevance of de novo mutations to the aetiology of ASD has been demonstrated. Current guidelines recommend chromosomal microarray (CMA) and a FMR1 testing as first-tier tests, but there is increasing evidence that support the use of NGS for the diagnosis of NDDs. Specifically in ASD, it has not been extensively evaluated and, thus, we performed and compared the clinical utility of CMA, FMR1 testing, and/or whole exome sequencing (WES) in a cohort of 343 ASD patients. We achieved a global diagnostic rate of 12.8% (44/343), the majority of them being characterised by WES (33/44; 75%) compared to CMA (9/44; 20.4%) or FMR1 testing (2/44; 4.5%). Taking into account the age at which genetic testing was carried out, we identified a causal genetic alteration in 22.5% (37/164) of patients over 5 years old, but only in 3.9% (7/179) of patients under this age. Our data evidence the higher diagnostic power of WES compared to CMA in the study of ASD and support the implementation of WES as a first-tier test for the genetic diagnosis of this disorder, when there is no suspicion of fragile X syndrome.