Interest of High-throughput Sequencing of RNAs for the Diagnosis of Heterogeneous Genetic Diseases

The advent of high throughput genomic DNA sequencing has led to major advances in the diagnosis of genetic diseases of heterogeneous origin. Thus, our hospital laboratory has developed in recent years several diagnostic tests based on the targeted sequencing of coding sequences of gene panels (from about twenty genes for DNA repair diseases to nearly five hundred genes for the intellectual disability). These targeted analyzes, carried out by capture, have thus solved 25 to 80% of the cases according to the indications, without allowing the diagnosis of the totality of the patients.

For these negative cases, the search for mutations in the coding sequences was then extended to Whole Exome Sequencing, thus providing several additional diagnoses.

Patients still remain without diagnosis after this exome study. These could be complex cases of genetic or even non-genetic origin, but also monogenic pathologies linked to mutations that are not identifiable by coding sequence analyzes, and especially affecting messenger RNAs.