MED13L syndrome – MED13L gene

The MED13L syndrome is a developmental disorder, mainly characterized by developmental delay, intellectual disability and small differences in facial features. It is also known as Asadollahi-Rauch syndrome, MED13L-related intellectual disability, developmental delay-facial dysmorphism syndrome due to MED13L deficiency, or MED13L haploinsufficiency syndrome.

Other signs related to this process may include recurrent seizures; congenital heart defects such as transposition of the aorta and pulmonary artery, ventricular septal defect (VSD), patent foramen ovale (PFO), and / or tetralogy of Fallot; hypotonia; ataxia; delay or absence in the development of motor skills and language; typical characteristics of autism spectrum disorder, including repetitive behaviors and difficulties with social interaction. The facial features of individuals with MED13L syndrome are characterized by a sunken nasal bridge, bulbous nose, straight eyebrows, ascending palpebral fissures and pronounced Cupid's bow.

This process is due to mutations in the MED13L (mediator complex subunit 13L) gene, located on the long arm of chromosome 12 (12q24.21), which encodes a protein that participates in the regulation of genetic activity. Specifically, this gene encodes a subunit of the mediator complex that acts as a transcriptional coactivator for most genes transcribed with RNA polymerase II. This protein participates in the early development of the heart and brain.

The mutations of the MED13L gene related to this process impair the function of the MED13L protein or reduce the amount of protein present, which disrupts the normal control of genetic activity. However, it is not clear how these changes give rise to the characteristics of the MED13L syndrome.

The MED13L syndrome is inherited with an autosomal dominant pattern, which means that an altered copy of the MED13L gene in each cell is sufficient to express the process. Most cases of this condition are due to new mutations in the gene that occur during the formation of reproductive cells or early embryonic development. These cases occur in individuals without history of the syndrome in their family. In rare cases, the syndrome is inherited from a parent with mosaicism, which means that it has a mutation in the MED13L gene in a small number of cells, including reproductive cells, and does not show any signs or symptoms of the syndrome.

Tests performed in IVAMI: in IVAMI we perform the detection of mutations associated with the MED13L syndrome, by means of the complete PCR amplification of the exons of the MED13L gene, and their subsequent sequencing.

Recommended samples: non-coagulated blood obtained with EDTA for separation of blood leucocytes, or a card with a dried blood sample (IVAMI can mail the card to deposit the blood sample).