Lujan-Fryns syndrome

Lujan-Fryns syndrome is an X-linked genetic disorder that causes mild to moderate intellectual disability along with physical features resembling Marfan syndrome, such as a long narrow face, tall thin stature and elongated limbs. It results from a specific missense mutation in the MED12 gene on the X chromosome, in which serine replaces asparagine at position 1007 of the protein. Individuals with the syndrome often show autism-like behaviors, an elevated risk of schizophrenia, and agenesis of the corpus callosum, the absence of the structure that normally connects the brain's two hemispheres. Cardiac involvement, including dilation of the aortic root, can pose serious health risks. The syndrome follows X-linked dominant inheritance, so a single mutated copy is enough to cause it, and because males have only one X chromosome they typically show more severe features than females.