Sotos syndrome is a rare, autosomal dominant disorder caused by haploinsufficiency of the NSD1 gene.
The condition has a prevalence of approximately 1 in 14 000.
Main clinical features
Sotos syndrome is characterised by the clinical triad of increased growth (height and / or head circumference), a learning disability and a distinctive facial appearance.
Mutations/deletions of NSD1 can be identified using a combination of gene sequencing (Sanger or next generation sequencing approaches) and MLPA.
Management of Sotos syndrome aims to identify and treat the known clinical associations. Review is recommended on an annual basis. Tumour surveillance is not recommended.
NSD1 mutations and deletions are inherited in an autosomal dominant manner and therefore affected individuals have a 50% chance of passing the NSD1 abnormality to their offspring. However, there are surprisingly few families with multiple affected individuals in consecutive generations. Although germline mosaicism is a theoretical possibility, there have been no reported cases to date.