Clinical features of NSD1-positive Sotos syndrome

It is 40 years since the first case of Sotos syndrome was reported. For most of the past four decades the diagnosis of Sotos syndrome has been dependent on the subjective evaluation of clinical criteria, primarily whether the facial gestalt is present. The recent identification of NSD1 (Nuclear receptor-binding SET domain containing protein) mutations and deletions in the great majority of Sotos syndrome cases has allowed re-evaluation of defining and associated features of the condition. In this review we will present the clinical features of Sotos syndrome cases with proven abnormalities in NSD1. This has allowed redefinition of Sotos syndrome as a condition characterised by a typical facial gestalt, macrocephaly and learning difficulties. Childhood overgrowth, advanced bone age, cardiac and genitourinary anomalies, neonatal jaundice, neonatal hypotonia, seizures and scoliosis are all fairly common in children with Sotos syndrome. A mutation or microdeletion of NSD1 is diagnostic of Sotos syndrome.