Exome sequencing greatly expedites the progressive research of Mendelian diseases

The advent of whole-exome sequencing （WES） has facilitated the discovery of rare structure and functional genetic variants. Combining exome sequencing with linkage studies is one of the most efficient strategies in searching disease genes for Mendelian diseases. WES has achieved great success in the past three years for Mendelian disease genetics and has identified over 150 new Mendelian disease genes. We illustrate the workflow of exome capture and sequencing to highlight the advantages of WES. We also indicate the progress and limitations of WES that can potentially result in failure to identify disease-causing mutations in part of patients. With an affordable cost, WES is expected to become the most commonly used tool for Mendelian disease gene identification. The variants detected cumulatively from previous WES studies will be widely used in future clinical services.

Improving genetic diagnosis of Mendelian disease with RNA sequencing:a narrative review

Targeted sequencing and whole exome sequencing are the most common approaches used to detect causative variants in Mendelian diseases;however, using DNA-based sequencing techniques, the current molecular diagnostic yield is at best 50%. In recent years, RNA sequencing has been shown to be able to provide a genetic diagnosis in patients whose conditions were previously unable to be identified by DNA analysis. RNA sequencing can reveal expression outliers, aberrant splicing events, allele-specific expression, and new pathogenic variants, and as such can complement and expand on the traditional genomic methods used to diagnose Mendelian diseases. Therefore, RNA sequencing is expected to become a routine method for genetic diagnosis in the future. This article reviews the applications and challenges of RNA sequencing in the genetic diagnosis of Mendelian diseases.

Insights on the crosstalk between dendritic cells and helper T cells in novel genetic etiology for mendelian susceptible mycobacterial disease

Mendelian susceptibility to mycobacterial disease(MSMD)is an inherited predisposition to infections by Bacille-Calmette Guérin(BCG)vaccine or by environmental mycobacteria.The etiology of MSMD has been associated with up to nineteen different genetic mutations in interferon(IFN)-γ-related genes.1 Although mycobacteria susceptibility-associated genetic mutations are rare in the population,their diagnosis is crucial for an efficient and timely treatment.Kong et al.2 have recently described an autosomal recessive deficiency in the signal peptidase-like 2 A(SPPL2-a)as a new genetic etiology for MSMD in three patients that had suffered BCG dissemination disease.