Genetics
Mutations in the NSD1 gene cause Sotos syndrome. The NSD1 gene provides instructions for making a protein that is involved in normal growth and development. The function of this protein is unknown, however. In the Japanese population, the most common genetic change leading to Sotos syndrome deletes genetic material from the region of chromosome 5 containing the NSD1 gene. In other populations, small mutations within the NSD1 gene occur more frequently. Genetic changes involving the NSD1 gene prevent one copy of the gene from producing any functional protein. It is unclear how a reduced amount of this protein during development leads to learning disabilities, overgrowth, and the other features of Sotos syndrome.
About 95 percent of Sotos syndrome cases occur in people with no history of the disorder in their family. Most of these cases result from new mutations involving the NSD1 gene. A few families have been described with more than one affected family member. These cases helped researchers determine that Sotos syndrome has an autosomal dominant pattern of inheritance. Autosomal dominant inheritance means one copy of the altered gene in each cell is sufficient to cause the disorder.
Read more about this topic: Sotos Syndrome