NSD1 mutations in Sotos syndrome.

Sotos syndrome is a genetic disorder characterized by a typical facial appearance, macrocephaly, accelerated growth, developmental delay, and a variable range of associated abnormalities. The NSD1 gene was recently found to be responsible for Sotos syndrome, and more than 150 patients with NSD1 alterations have been identified. A significant ethnic difference is found in the prevalence of different types of mutation, with a high percentage of microdeletions identified in Japanese Sotos syndrome patients and with intragenic mutations in most non-Japanese patients. NSD1 aberrations are rather specific for Sotos syndrome, but have also been detected in patients lacking one or more major criteria of the disorder, namely overgrowth, macrocephaly, and advanced bone age. Thus, new diagnostic criteria should be considered. Studies have reported different frequencies of mutations versus non-mutations in Sotos syndrome, thus indicating allelic or locus hetereogeneity. Although some authors have suggested genotype/phenotype correlations, further studies are needed.