When there is a clear clinical diagnosis of a heterogeneous genetic pathology, exome sequencing is a good strategy to look for causal mutations of this illness or disability. Besides the reduction of genetic material needed, compared to whole genome sequencing, it is estimated that 85% of known mutations causing genetic diseases are located in the exome.
The exome refers to the set of coding and regulatory regions identified every gene in the genome.
How does it work?
Exome sequencing captures and sequences the coding portion of the genome and compares with reference sequences published in international databases. This helps to identify causal variants that could explain the disorder in the affected patient.
- Neurodevelopmental Disorders (TND)
- Inborn errors of metabolism (IEM)
- Hereditary blindness
- Alterations in hematopoiesis
- Genetic Epilepsy
Mental / autism delay exome sequencing
Neurodevelopmental Disabilities (NDD) affect about 2.5-3 % of the pediatric population. In a significant percentage of cases, these disorders are genetic. Also the subgroup of Autism Spectrum Disorders (ASD) includes autism, pervasive nonspecific development disorders, and Asperger syndrome. These are often comorbid with other medical conditions such as intellectual disabilities, who may also have a genetic cause in many cases.
The genetic causes of autism are varied. Some chromosomal abnormalities are visible to karyotype (3-5 %) or other copy number variants (10 %) only detectable by array CGH (CarioChip® Postnatal). Moreover, the exome study can detect mutations in specific genes (as MECP2, or PTEN FMR1) that explain up to 10% of cases, and an additional ̴10% of cases may be due to specific alterations in other genes. In total, according to current knowledge and available technology, it is estimated that is possible to identify the genetic etiology in 30-40 % of individuals with ASD1.
Main TND list of affordable by exome request:
Cardio facial cutaneous syndrome
Cornelia Lange syndrome
1 Schaefer GB, Mendelsohn NJ; Professional Practice and Guidelines Committee. Clinical genetics evaluation in identifying the etiology of autism spectrum disorders: 2013 guideline revisions. Genet Med. 2013 May; 15 (5):399-407. Doi:10.1038/gim.2013.32 Epub 2013 Mar 21. PubMed PMID: 23519317.