Use of Targeted Exome Sequencing for Molecular Diagnosis of Skeletal Disorders

<div><p>Genetic disorders of the skeleton comprise a large group of more than 450 clinically distinct and genetically heterogeneous diseases associated with mutations in more than 300 genes. Achieving a definitive diagnosis is complicated due to the genetic heterogeneity of these disorders, their individual rarity and their diverse radiographic presentations. We used targeted exome sequencing and designed a 1.4Mb panel for simultaneous testing of more than 4,800 exons in 309 genes involved in skeletal disorders. DNA from 69 individuals from 66 families with a known or suspected clinical diagnosis of a skeletal disorder was analyzed. Of 36 cases with a specific clinical hypothesis with a known genetic basis, mutations were identified for eight cases (22%). Of 20 cases with a suspected skeletal disorder but without a specific diagnosis, four causative mutations were identified. Also included were 11 cases with a specific skeletal disorder but for which there was at the time no known associated gene. For these cases, one mutation was identified in a known skeletal disease genes, and re-evaluation of the clinical phenotype in this case changed the diagnoses from osteodysplasia syndrome to Apert syndrome. These results suggest that the NGS panel provides a fast, accurate and cost-effective molecular diagnostic tool for identifying mutations in a highly genetically heterogeneous set of disorders such as genetic skeletal disorders. The data also stress the importance of a thorough clinical evaluation before DNA sequencing. The strategy should be applicable to other groups of disorders in which the molecular basis is largely known.</p></div

Summary of causative mutations identified after molecular analysis in the investigated cases.

<p>*HGMD Access code.</p><p>^#Variant Classification according to the ACMG and AMP guidelines [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0138314#pone.0138314.ref078" target="_blank">78</a>]. NA: Not applicable.</p><p>Summary of causative mutations identified after molecular analysis in the investigated cases.</p

Analysis of the molecular data obtained by targeted exome sequencing.

<p>Analysis of the molecular data obtained by targeted exome sequencing.</p