“Whole Exome Sequencing” or “WES” is a Next Generation Sequencing (NGS) test that simultaneously analyzes nearly all the exons of the 20,000 genes in the human genome + CNVs (Copy Number Variation) + mitochondrial DNA. Although exons represent 2% of the genome, about 85% of the genetic variations that cause disease are located in these regions. This test is a powerful tool for diagnosing thousands of genetic diseases. The test can be requested for patients with suspected genetic diseases (for example: skeletal dysplasias and muscular dystrophies) and for patients with a clinical condition that is suggestive of a genetic disease, but without a specific suspicion (Example: intellectual disability, congenital anomalies etc). WES can also be requested when there is a clinical condition that can be caused by multiple different genes, for which there is no panel containing all the genes of interest. It is important to emphasize that WES does not identify genetic diseases that are caused by nucleotide expansions, variations in non-coding regions of the genome, uniparental disomy (UPD) or imprinting. The Mendelics WES test is very comprehensive, including the analysis of point mutations (substitutions), indels (small insertions and deletions), CNVs (Copy Number Variation) and mitochondrial DNA.